PRIORITY CLAIM

This application is a continuation of U.S. patent application Ser. No. 14/627,733, filed Feb. 20, 2015, which is a continuation of U.S. application Ser. No. 13/915,320, filed Jun. 11, 2013, which is a continuation of U.S. application Ser. No. 12/990,202, filed Dec. 17, 2010, which is a United States National Stage entry of International Application Number PCT/US09/42926, filed May 6, 2009, which claims priority to U.S. Provisional Patent Application Ser. No. 61/052,061, filed May 9, 2008, the entire contents of each of which is incorporated herein by reference.

BACKGROUND

Poly(ethylene carbonate) (PEC) is a flexible, biocompatible, and biodegradable material with high gas barrier properties, particularly for O₂. It is made via the ring opening polymerization of ethylene carbonate (EC) or by the copolymerization of ethylene oxide (EO) and CO₂. Ring opening polymerization of EC initiated by KOH or Sn(OAc)₂at high temperature leads to poly(ethylene oxide-co-ether carbonate) rather than PEC. The high reaction temperatures required for this route cause the elimination of CO₂during polymerization. The alternating copolymerization of epoxides and CO₂to form polycarbonates was originally discovered by Inoue in 1969. Since then, numerous catalyst systems have been developed for epoxide/CO₂copolymerization (see, for example, Coates and Moore, Angew. Chem. Int. Ed. 2004, 43, 6618-6639; Super and Beckman, Trends Polym. Sci. 1997, 5, 236-240; Darensbourg, and Holtcamp, Coord. Chem. Rev. 1996, 153, 155-174). Various systems for EO/CO₂copolymerization based on Zn, Al, or double metal cyanide species have been reported; however, they require high CO₂pressure and suffer from low catalytic activities.

SUMMARY

The present disclosure provides, in part, methods of synthesizing poly(ethylene carbonate) polymers from the reaction of ethylene oxide (EO) and carbon dioxide (CO₂) in the presence of a metal complex. The present disclosure also provides novel metal complexes. In particular, the inventors have found that N,N′-bis(salicydene)-1,2-cyclohexyldiamine (salcy) metal complexes are effective in this polymerization reaction, and particularly in providing poly(ethylene carbonate) polymers with low ether content.

In one aspect, the metal complexes as described herein are of the formula (I):

[Image Omitted]

wherein:

M is a metal selected from zinc, cobalt, chromium, aluminum, titanium, ruthenium or manganese;

X is absent or is a nucleophilic ligand;

each instance of R¹, R², and R³is, independently, selected from hydrogen, halogen, optionally substituted aliphatic, optionally substituted heteroaliphatic, optionally substituted aryl, and optionally substituted heteroaryl, or R¹and R², or R²and R³, are joined to form an optionally substituted aryl or optionally substituted heteroaryl ring; and

Ring A forms an optionally substituted 5- to 6-membered ring.

In another aspect, the present disclosure provides a method of synthesizing a poly(ethylene carbonate) polymer, wherein the polymer is made up of Y, and optionally Z, and wherein the percentage of Y is greater than the percentage of Z,

[Image Omitted]

the method comprising reacting ethylene oxide and carbon dioxide in the presence of a metal complex.

In certain embodiments, the above method comprises a metal complex of formula (I), as described above and herein.

This application refers to various issued patent, published patent applications, journal articles, and other publications, all of which are incorporated herein by reference.

The details of one or more embodiments are set forth herein.

Definitions

Definitions of specific functional groups and chemical terms are described in more detail below. For purposes of this disclosure, the chemical elements are identified in accordance with the Periodic Table of the Elements, CAS version, Handbook of Chemistry and Physics, 75^thEd., inside cover, and specific functional groups are generally defined as described therein. Additionally, general principles of organic chemistry, as well as specific functional moieties and reactivity, are described in Organic Chemistry, Thomas Sorrell, University Science Books, Sausalito, 1999; Smith and March March's Advanced Organic Chemistry, 5^thEdition, John Wiley & Sons, Inc., New York, 2001; Larock, Comprehensive Organic Transformations, VCH Publishers, Inc., New York, 1989; Carruthers, Some Modern Methods of Organic Synthesis, 3^rdEdition, Cambridge University Press, Cambridge, 1987; the entire contents of each of which are incorporated herein by reference.

Certain compounds of the present disclosure can comprise one or more asymmetric centers, and thus can exist in various isomeric forms, e.g., stereoisomers and/or diastereomers. Thus, inventive compounds and compositions thereof may be in the form of an individual enantiomer, diastereomer or geometric isomer, or may be in the form of a mixture of stereoisomers. In certain embodiments, the compounds of the disclosure are enantiopure compounds. In certain other embodiments, mixtures of stereoisomers or diastereomers are provided.

Furthermore, certain compounds, as described herein may have one or more double bonds that can exist as either the Z or E isomer, unless otherwise indicated.

The disclosure additionally encompasses the compounds as individual isomers substantially free of other isomers and alternatively, as mixtures of various isomers, e.g., racemic mixtures of stereoisomers. In addition to the above-mentioned compounds per se, this disclosure also encompasses pharmaceutically acceptable derivatives of these compounds and compositions comprising one or more compounds.

Where a particular enantiomer is preferred, it may, in some embodiments be provided substantially free of the opposite enantiomer, and may also be referred to as “optically enriched.” “Optically-enriched,” as used herein, means that the compound is made up of a significantly greater proportion of one enantiomer. In certain embodiments the compound is made up of at least about 90% by weight of a preferred enantiomer. In other embodiments the compound is made up of at least about 95%, 98%, or 99% by weight of a preferred enantiomer. Preferred enantiomers may be isolated from racemic mixtures by any method known to those skilled in the art, including chiral high pressure liquid chromatography (HPLC) and the formation and crystallization of chiral salts or prepared by asymmetric syntheses. See, for example, Jacques, et al., Enantiomers, Racemates and Resolutions (Wiley Interscience, New York, 1981); Wilen, S. H., et al., Tetrahedron 33:2725 (1977); Eliel, E. L. Stereochemistry of Carbon Compounds (McGraw-Hill, N Y, 1962); Wilen, S. H. Tables of Resolving Agents and Optical Resolutions p. 268 (E. L. Eliel, Ed., Univ. of Notre Dame Press, Notre Dame, Ind. 1972).

The terms “halo” and “halogen” as used herein refer to an atom selected from fluorine (fluoro, —F), chlorine (chloro, —Cl), bromine (bromo, —Br), and iodine (iodo, —I).

The term “aliphatic” or “aliphatic group”, as used herein, denotes a hydrocarbon moiety that may be straight-chain (i.e., unbranched), branched, or cyclic (including fused, bridging, and spiro-fused polycyclic) and may be completely saturated or may contain one or more units of unsaturation, but which is not aromatic. Unless otherwise specified, aliphatic groups contain 1-12 carbon atoms. In certain embodiments, aliphatic groups contain 1-8 carbon atoms. In certain embodiments, aliphatic groups contain 1-6 carbon atoms. In some embodiments, aliphatic groups contain 1-5 carbon atoms, in some embodiments, aliphatic groups contain 1-4 carbon atoms, in yet other embodiments aliphatic groups contain 1-3 carbon atoms, and in yet other embodiments aliphatic groups contain 1-2 carbon atoms. Suitable aliphatic groups include, but are not limited to, linear or branched, alkyl, alkenyl, and alkynyl groups, and hybrids thereof such as (cycloalkyl)alkyl, (cycloalkenyl)alkyl or (cycloalkyl)alkenyl.

The term “unsaturated”, as used herein, means that a moiety has one or more double or triple bonds.

The terms “cycloaliphatic”, “carbocycle”, or “carbocyclic”, used alone or as part of a larger moiety, refer to a saturated or partially unsaturated cyclic aliphatic monocyclic or bicyclic ring systems, as described herein, having from 3 to 12 members, wherein the aliphatic ring system is optionally substituted as defined above and described herein. Cycloaliphatic groups include, without limitation, cyclopropyl, cyclobutyl, cyclopentyl, cyclopentenyl, cyclohexyl, cyclohexenyl, cycloheptyl, cycloheptenyl, cyclooctyl, cyclooctenyl, and cyclooctadienyl. In some embodiments, the cycloalkyl has 3-6 carbons. The terms “cycloaliphatic”, “carbocycle” or “carbocyclic” also include aliphatic rings that are fused to one or more aromatic or nonaromatic rings, such as decahydronaphthyl or tetrahydronaphthyl, where the radical or point of attachment is on the aliphatic ring.

The term “alkyl,” as used herein, refers to saturated, straight- or branched-chain hydrocarbon radicals derived from an aliphatic moiety containing between one and six carbon atoms by removal of a single hydrogen atom. Unless otherwise specified, alkyl groups contain 1-12 carbon atoms. In certain embodiments, alkyl groups contain 1-8 carbon atoms. In certain embodiments, alkyl groups contain 1-6 carbon atoms. In some embodiments, alkyl groups contain 1-5 carbon atoms, in some embodiments, alkyl groups contain 1-4 carbon atoms, in yet other embodiments alkyl groups contain 1-3 carbon atoms, and in yet other embodiments alkyl groups contain 1-2 carbon atoms. Examples of alkyl radicals include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, iso-butyl, sec-butyl, sec-pentyl, iso-pentyl, tert-butyl, n-pentyl, neopentyl, n-hexyl, sec-hexyl, n-heptyl, n-octyl, n-decyl, n-undecyl, dodecyl, and the like.

The term “alkenyl,” as used herein, denotes a monovalent group derived from a straight- or branched-chain aliphatic moiety having at least one carbon-carbon double bond by the removal of a single hydrogen atom. Unless otherwise specified, alkenyl groups contain 2-12 carbon atoms. In certain embodiments, alkenyl groups contain 2-8 carbon atoms. In certain embodiments, alkenyl groups contain 2-6 carbon atoms. In some embodiments, alkenyl groups contain 2-5 carbon atoms, in some embodiments, alkenyl groups contain 2-4 carbon atoms, in yet other embodiments alkenyl groups contain 2-3 carbon atoms, and in yet other embodiments alkenyl groups contain 2 carbon atoms. Alkenyl groups include, for example, ethenyl, propenyl, butenyl, 1-methyl-2-buten-1-yl, and the like.

The term “alkynyl,” as used herein, refers to a monovalent group derived from a straight- or branched-chain aliphatic moiety having at least one carbon-carbon triple bond by the removal of a single hydrogen atom. Unless otherwise specified, alkynyl groups contain 2-12 carbon atoms. In certain embodiments, alkynyl groups contain 2-8 carbon atoms. In certain embodiments, alkynyl groups contain 2-6 carbon atoms. In some embodiments, alkynyl groups contain 2-5 carbon atoms, in some embodiments, alkynyl groups contain 2-4 carbon atoms, in yet other embodiments alkynyl groups contain 2-3 carbon atoms, and in yet other embodiments alkynyl groups contain 2 carbon atoms. Representative alkynyl groups include, but are not limited to, ethynyl, 2-propynyl (propargyl), 1-propynyl, and the like.

The term “aryl” used alone or as part of a larger moiety as in “aralkyl”, “aralkoxy”, or “aryloxyalkyl”, refers to monocyclic and polycyclic ring systems having a total of five to 20 ring members, wherein at least one ring in the system is aromatic and wherein each ring in the system contains three to twelve ring members. The term “aryl” may be used interchangeably with the term “aryl ring”. In certain embodiments of the present disclosure, “aryl” refers to an aromatic ring system which includes, but is not limited to, phenyl, biphenyl, naphthyl, anthracyl and the like, which may bear one or more substituents. Also included within the scope of the term “aryl”, as it is used herein, is a group in which an aromatic ring is fused to one or more additional rings, such as benzofuranyl, indanyl, phthalimidyl, naphthimidyl, phenantriidinyl, or tetrahydronaphthyl, and the like.

The terms “heteroaryl” and “heteroar-”, used alone or as part of a larger moiety, e.g., “heteroaralkyl”, or “heteroaralkoxy”, refer to groups having 5 to 14 ring atoms, preferably 5, 6, or 9 ring atoms; having 6, 10, or 14 π electrons shared in a cyclic array; and having, in addition to carbon atoms, from one to five heteroatoms. The term “heteroatom” refers to nitrogen, oxygen, or sulfur, and includes any oxidized form of nitrogen or sulfur, and any quaternized form of a basic nitrogen. Heteroaryl groups include, without limitation, thienyl, furanyl, pyrrolyl, imidazolyl, pyrazolyl, triazolyl, tetrazolyl, oxazolyl, isoxazolyl, oxadiazolyl, thiazolyl, isothiazolyl, thiadiazolyl, pyridyl, pyridazinyl, pyrimidinyl, pyrazinyl, indolizinyl, purinyl, naphthyridinyl, benzofuranyl and pteridinyl. The terms “heteroaryl” and “heteroar-”, as used herein, also include groups in which a heteroaromatic ring is fused to one or more aryl, cycloaliphatic, or heterocyclyl rings, where the radical or point of attachment is on the heteroaromatic ring. Nonlimiting examples include indolyl, isoindolyl, benzothienyl, benzofuranyl, dibenzofuranyl, indazolyl, benzimidazolyl, benzthiazolyl, quinolyl, isoquinolyl, cinnolinyl, phthalazinyl, quinazolinyl, quinoxalinyl, 4H-quinolizinyl, carbazolyl, acridinyl, phenazinyl, phenothiazinyl, phenoxazinyl, tetrahydroquinolinyl, tetrahydroisoquinolinyl, and pyrido[2,3-b]-1,4-oxazin-3(4H)-one. A heteroaryl group may be mono- or bicyclic. The term “heteroaryl” may be used interchangeably with the terms “heteroaryl ring”, “heteroaryl group”, or “heteroaromatic”, any of which terms include rings that are optionally substituted. The term “heteroaralkyl” refers to an alkyl group substituted by a heteroaryl, wherein the alkyl and heteroaryl portions independently are optionally substituted.

As used herein, the terms “heterocycle”, “heterocyclyl”, “heterocyclic radical”, and “heterocyclic ring” are used interchangeably and refer to a stable 5- to 7-membered monocyclic or 7-14-membered bicyclic heterocyclic moiety that is either saturated or partially unsaturated, and having, in addition to carbon atoms, one or more, preferably one to four, heteroatoms, as defined above. When used in reference to a ring atom of a heterocycle, the term “nitrogen” includes a substituted nitrogen. As an example, in a saturated or partially unsaturated ring having 0-3 heteroatoms selected from oxygen, sulfur or nitrogen, the nitrogen may be N (as in 3,4-dihydro-2H-pyrrolyl), NH (as in pyrrolidinyl), or ⁺NR (as in N-substituted pyrrolidinyl).

A heterocyclic ring can be attached to its pendant group at any heteroatom or carbon atom that results in a stable structure and any of the ring atoms can be optionally substituted. Examples of such saturated or partially unsaturated heterocyclic radicals include, without limitation, tetrahydrofuranyl, tetrahydrothienyl, pyrrolidinyl, pyrrolidonyl, piperidinyl, pyrrolinyl, tetrahydroquinolinyl, tetrahydroisoquinolinyl, decahydroquinolinyl, oxazolidinyl, piperazinyl, dioxanyl, dioxolanyl, diazepinyl, oxazepinyl, thiazepinyl, morpholinyl, and quinuclidinyl. The terms “heterocycle”, “heterocyclyl”, “heterocyclyl ring”, “heterocyclic group”, “heterocyclic moiety”, and “heterocyclic radical”, are used interchangeably herein, and also include groups in which a heterocyclyl ring is fused to one or more aryl, heteroaryl, or cycloaliphatic rings, such as indolinyl, 3H-indolyl, chromanyl, phenanthridinyl, or tetrahydroquinolinyl, where the radical or point of attachment is on the heterocyclyl ring. A heterocyclyl group may be mono- or bicyclic. The term “heterocyclylalkyl” refers to an alkyl group substituted by a heterocyclyl, wherein the alkyl and heterocyclyl portions independently are optionally substituted.

As used herein, the term “partially unsaturated” refers to a ring moiety that includes at least one double or triple bond. The term “partially unsaturated” is intended to encompass rings having multiple sites of unsaturation, but is not intended to include aryl or heteroaryl moieties, as herein defined.

As described herein, compounds of the disclosure may contain “optionally substituted” moieties. In general, the term “substituted”, whether preceded by the term “optionally” or not, means that one or more hydrogens of the designated moiety are replaced with a suitable substituent. Unless otherwise indicated, an “optionally substituted” group may have a suitable substituent at each substitutable position of the group, and when more than one position in any given structure may be substituted with more than one substituent selected from a specified group, the substituent may be either the same or different at every position. Combinations of substituents envisioned by this disclosure are preferably those that result in the formation of stable or chemically feasible compounds. The term “stable”, as used herein, refers to compounds that are not substantially altered when subjected to conditions to allow for their production, detection, and, in certain embodiments, their recovery, purification, and use for one or more of the purposes disclosed herein.

Suitable monovalent substituents on a substitutable carbon atom of an “optionally substituted” group are independently halogen; —(CH₂)_0-4R^∘; —(CH₂)_0-4OR^∘; —O—(CH₂)_0-4C(O)OR^∘; —(CH₂)_0-4CH(OR^∘)₂; —(CH₂)_0-4SR^∘; —(CH₂)_0-4Ph, which may be substituted with R^∘; —(CH₂)_0-4O(CH₂)_0-1Ph which may be substituted with R^∘; —CH═CHPh, which may be substituted with R^∘; —NO₂; —CN; —N₃; —(CH₂)_0-4N(R^∘)₂; —(CH₂)_0-4N(R^∘)C(O)R^∘; —N(R^∘)C(S)R^∘; —(CH₂)_0-4N(R^∘)C(O)NR^∘₂; —N(R^∘)C(S)NR^∘₂; —(CH₂)_0-4N(R^∘)C(O)OR^∘; —N(R^∘)N(R^∘)C(O)R^∘; —N(R^∘)N(R^∘)C(O)NR^∘₂; —N(R^∘)N(R^∘)C(O)OR^∘; —(CH₂)_0-4C(O)R^∘; —C(S)R^∘; —(CH₂)_0-4C(O)OR^∘; —(CH₂)_0-4C(O)N(R^∘)₂; —(CH₂)_0-4C(O)SR^∘; —(CH₂)_0-4C(O)OSiR^∘₃; —(CH₂)_0-4OC(O)R^∘; —OC(O)(CH₂)_0-4SR—, SC(S)SR^∘; —(CH₂)_0-4SC(O)R; —(CH₂)_0-4C(O)NR₂; —C(S)NR^∘₂; —C(S)SR^∘; —SC(S)SR^∘, —(CH₂)_0-4OC(O)NR^∘₂; —C(O)N(OR^∘)R^∘; —C(O)C(O)R^∘; —C(O)CH₂C(O)R^∘; —C(NOR^∘)R^∘; —(CH₂)_0-4SSR^∘; —(CH₂)_0-4S(O)₂R^∘; —(CH₂)_0-4S(O)₂OR^∘; —(CH₂)_0-4OS(O)₂R^∘; —S(O)₂NR^∘₂; —(CH₂)_0-4S(O)R^∘; —N(R^∘)S(O)₂NR^∘₂; —N(R^∘)S(O)₂R^∘; —N(OR^∘)R^∘; —C(NH)NR^∘₂; —P(O)₂R^∘; —P(O)R^∘₂; —OP(O)R^∘₂; —OP(O)(OR^∘)₂; SiR^∘₃; —(C_1-4straight or branched alkylene)O—N(R^∘)₂; or —(C_1-4straight or branched alkylene)C(O)O—N(R^∘)₂, wherein each R^∘ may be substituted as defined below and is independently hydrogen, C_1-8aliphatic, —CH₂Ph, —O(CH₂)_0-1Ph, or a 5-6-membered saturated, partially unsaturated, or aryl ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur, or, notwithstanding the definition above, two independent occurrences of R^∘, taken together with their intervening atom(s), form a 3-12-membered saturated, partially unsaturated, or aryl mono- or polycyclic ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur, which may be substituted as defined below.

Suitable monovalent substituents on R^∘ (or the ring formed by taking two independent occurrences of R^∘ together with their intervening atoms), are independently halogen, —(CH₂)O₂R^●, -(haloR^●), —(CH₂)_0-2OH, —(CH₂)_0-2OR^●, —(CH₂)_0-2CH(OR^●)₂; —O(haloR^●), —CN, —N₃, —(CH₂)_0-2C(O)R^●, —(CH₂)_0-2C(O)OH, —(CH₂)_0-2C(O)OR^●, —(CH₂)_0-4C(O)N(R^∘)₂; —(CH₂)_0-2SR^●, —(CH₂)_0-2SH, —(CH₂)_0-2NH₂, —(CH₂)_0-2NHR^●, —(CH₂)_0-2NR^●₂, —NO₂, —SiR^●₃, —OSiR^●₃, —C(O)SR^●, —(C_1-4straight or branched alkylene)C(O)OR^●, or —SSR^● wherein each R^● is unsubstituted or where preceded by “halo” is substituted only with one or more halogens, and is independently selected from C_1-4aliphatic, —CH₂Ph, —O(CH₂)_0-1Ph, or a 5-6-membered saturated, partially unsaturated, or aryl ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur. Suitable divalent substituents on a saturated carbon atom of R^∘ include ═O and ═S.

Suitable divalent substituents on a saturated carbon atom of an “optionally substituted” group include the following: ═O, ═S, ═NNR*₂, ═NNHC(O)R*, ═NNHC(O)OR*, ═NNHS(O)₂R*, ═NR*, ═NOR*, —O(C(R*₂))_2-3O—, or —S(C(R*₂))_2-3S—, wherein each independent occurrence of R* is selected from hydrogen, C_1-6aliphatic which may be substituted as defined below, or an unsubstituted 5-6-membered saturated, partially unsaturated, or aryl ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur. Suitable divalent substituents that are bound to vicinal substitutable carbons of an “optionally substituted” group include: —O(CR*₂)_2-3O—, wherein each independent occurrence of R* is selected from hydrogen, C_1-6aliphatic which may be substituted as defined below, or an unsubstituted 5-6-membered saturated, partially unsaturated, or aryl ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur.

Suitable substituents on the aliphatic group of R* include halogen, —R^●, -(haloR^●), —OH, —OR^●, —O(haloR^∘), —CN, —C(O)OH, —C(O)OR^●, —NH₂, —NHR^●, —NR^●₂, or —NO₂, wherein each R^● is unsubstituted or where preceded by “halo” is substituted only with one or more halogens, and is independently C_1-4aliphatic, —CH₂Ph, —O(CH₂)_0-1Ph, or a 5-6-membered saturated, partially unsaturated, or aryl ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur.

Suitable substituents on a substitutable nitrogen of an “optionally substituted” group include —R^†, —NR^†₂, —C(O)R^†, —C(O)OR^†, —C(O)C(O)R^†, —C(O)CH₂C(O)R^†, —S(O)₂R^†, —S(O)₂NR^†₂, —C(S)NR^†₂, —C(NH)NR^†₂, or —N(R^†)S(O)₂R^†; wherein each R^† is independently hydrogen, C_1-6aliphatic which may be substituted as defined below, unsubstituted —OPh, or an unsubstituted 5-6-membered saturated, partially unsaturated, or aryl ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur, or, notwithstanding the definition above, two independent occurrences of R^†, taken together with their intervening atom(s) form an unsubstituted 3-12-membered saturated, partially unsaturated, or aryl mono- or bicyclic ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur. A substitutable nitrogen may be substituted with three R^† substituents to provide a charged ammonium moiety —N⁺(R^†)₃, wherein the ammonium moiety is further complexed with a suitable counterion.

Suitable substituents on the aliphatic group of R^† are independently halogen, —R^●, -(haloR^●), —OH, —OR^●, —O(haloR^●), —CN, —C(O)OH, —C(O)OR^●, —NH₂, —NHR^●, —NR^●₂, or —NO₂, wherein each R^● is unsubstituted or where preceded by “halo” is substituted only with one or more halogens, and is independently C_1-4aliphatic, —CH₂Ph, —O(CH₂)_0-1Ph, or a 5-6-membered saturated, partially unsaturated, or aryl ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur.

As used herein, the term “tautomer” includes two or more interconvertable compounds resulting from at least one formal migration of a hydrogen atom and at least one change in valency (e.g., a single bond to a double bond, a triple bond to a single bond, or vice versa). The exact ratio of the tautomers depends on several factors, including temperature, solvent, and pH. Tautomerizations (i.e., the reaction providing a tautomeric pair) may catalyzed by acid or base. Exemplary tautomerizations include keto-to-enol; amide-to-imide; lactam-to-lactim; enamine-to-imine; and enamine-to-(a different) enamine tautomerizations.

As used herein, the term “isomers” includes any and all geometric isomers and stereoisomers. For example, “isomers” include cis- and trans-isomers, E- and Z-isomers, R- and S-enantiomers, diastereomers, (D)-isomers, (L)-isomers, racemic mixtures thereof, and other mixtures thereof, as falling within the scope of the disclosure. For instance, an isomer/enantiomer may, in some embodiments, be provided substantially free of the corresponding enantiomer, and may also be referred to as “optically enriched.” “Optically-enriched,” as used herein, means that the compound is made up of a significantly greater proportion of one enantiomer. In certain embodiments the compound of the present disclosure is made up of at least about 90% by weight of a preferred enantiomer. In other embodiments the compound is made up of at least about 95%, 98%, or 99% by weight of a preferred enantiomer. Preferred enantiomers may be isolated from racemic mixtures by any method known to those skilled in the art, including chiral high pressure liquid chromatography (HPLC) and the formation and crystallization of chiral salts or prepared by asymmetric syntheses. See, for example, Jacques, et al., Enantiomers, Racemates and Resolutions (Wiley Interscience, New York, 1981); Wilen, S. H., et al., Tetrahedron 33:2725 (1977); Eliel, E. L. Stereochemistry of Carbon Compounds (McGraw-Hill, N Y, 1962); Wilen, S. H. Tables of Resolving Agents and Optical Resolutions p. 268 (E. L. Eliel, Ed., Univ. of Notre Dame Press, Notre Dame, Ind. 1972).

As used herein, “polymorph” refers to a crystalline inventive compound existing in more than one crystalline form/structure. When polymorphism exists as a result of difference in crystal packing it is called packing polymorphism. Polymorphism can also result from the existence of different conformers of the same molecule in conformational polymorphism. In pseudopolymorphism the different crystal types are the result of hydration or solvation.

BRIEF DESCRIPTION OF THE FIGURES

Figure JA. ¹H NMR spectra (300 MHz) of PEC obtained by catalyst 1 in conjunction with [PPN]Cl.

FIG. 1B. ¹H NMR spectra (300 MHz) of PEC obtained by catalyst 4 in conjunction with [PPN]Cl.

FIG. 2. ¹H NMR spectra of PEC and PEO.

FIG. 3. (Salcy)CoOBzF₅induced ethylene oxide (EO) polymerization in the presence of PPNCl. The catalytic activity is strongly dependant on the PPNCl/Co ratio.

FIG. 4A. TGA analyses of PEO-b-PEC.

FIG. 4B. DSC analyses of PEO-b-PEC.

DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS

As generally described above, the present disclosure provides methods of synthesizing poly(ethylene carbonate) compositions from ethylene oxide and carbon dioxide in the presence of a metal complex. In certain embodiments, the poly(ethylene carbonate) polymer is an alternating polymer. In certain embodiments, the poly(ethylene carbonate) polymer is a tapered co-polymer of polyethylene oxide and polyethylene carbonate. In certain embodiments, the poly(ethylene carbonate) polymer is a block co-polymer of polyethylene oxide and polyethylene carbonate.

As is generally understood from the description as provided herein, poly(ethylene carbonate) polymers of the present disclosure encompass poly(ethylene carbonate) (PEC), as well as polymers which comprise poly(ethylene carbonate), such as, for example, polyethylene oxide-co-polyethylene carbonate.

The present disclosure also provides novel metal complexes of the formula (I) as is described in detail below.

I. Metal Complexes

In certain embodiments, the metal complex is of the formula (I):

[Image Omitted]

wherein:

M is a metal selected from zinc, cobalt, chromium, aluminum, titanium, ruthenium and manganese;

X is absent or is a nucleophilic ligand;

Ring A forms an optionally substituted 5- to 6-membered ring.

In certain embodiments, the metal is aluminum. In certain embodiments, the metal is chromium. In certain embodiments, the metal is zinc. In certain embodiments, the metal is titanium. In certain embodiments, the metal is ruthenium. In certain embodiments, the metal is manganese. In certain embodiments, the metal is cobalt. In certain embodiments, wherein the metal is cobalt, the cobalt has a valency of +3 (i.e., Co(III)).

In certain embodiments, the metal complex is a metal catalyst.

In certain embodiments, X is absent. However, in certain embodiments, X is a nucleophilic ligand. Exemplary nucleophilic ligands include, but are not limited to, —OR^x, —SR^x, —O(C═O)R^x, —O(C═O)OR^x, —O(C═O)N(R)₂, —N(R^x)(C═O)R^x, —NC, —CN, halo (e.g., —Br, —I, —Cl), —N₃, —O(SO₂)R^xand —OPR^x₃, wherein each R^xis, independently, selected from hydrogen, optionally substituted aliphatic, optionally substituted heteroaliphatic, optionally substituted aryl and optionally substituted heteroaryl.

In certain embodiments, X is —O(C═O)R^x, wherein R^xis selected from optionally substituted aliphatic, fluorinated aliphatic, optionally substituted heteroaliphatic, optionally substituted aryl, fluorinated aryl, and optionally substituted heteroaryl.

For example, in certain embodiments, X is —O(C═O)R^x, wherein R^xis optionally substituted aliphatic. In certain embodiments, X is —O(C═O)R^x, wherein R^xis optionally substituted alkyl and fluoroalkyl. In certain embodiments, X is —O(C═O)CH₃or —O(C═O)CF₃.

Furthermore, in certain embodiments, X is —O(C═O)R^x, wherein R^xis optionally substituted aryl, fluoroaryl, or heteroaryl. In certain embodiments, X is —O(C═O)R^x, wherein R^xis optionally substituted aryl. In certain embodiments, X is —O(C═O)R^x, wherein R^xis optionally substituted phenyl. In certain embodiments, X is —O(C═O)C₆H₅or —O(C═O)C₆F₅.

In certain embodiments, X is —OR^x, wherein R^xis selected from optionally substituted aliphatic, optionally substituted heteroaliphatic, optionally substituted aryl, and optionally substituted heteroaryl.

For example, in certain embodiments, X is —OR^x, wherein R^xis optionally substituted aryl. In certain embodiments, X is —OR^x, wherein R^xis optionally substituted phenyl. In certain embodiments, X is —OC₆H₅or —OC₆H₂(2,4-NO₂).

In certain embodiments, X is halo. In certain embodiments, X is —Br. In certain embodiments, X is —Cl. In certain embodiments, X is —I.

In certain embodiments, X is —O(SO₂)R^x. In certain embodiments X is —OTs. In certain embodiments X is —OSO₂Me, In certain embodiments X is —OSO₂CF₃.

In certain embodiments, X is —N₃.

In certain embodiments, X is —NC

In certain embodiments, X is —CN.

In certain embodiments, Ring A forms an optionally substituted 5-membered ring. In certain embodiments, Ring A forms an optionally substituted cyclopentyl ring. In certain embodiments, Ring A forms an optionally substituted 5-membered aryl ring.

In certain embodiments, Ring A forms an optionally substituted 6-membered ring. In certain embodiments, Ring A forms an optionally substituted cyclohexyl ring. In certain embodiments, Ring A forms an optionally substituted 6-membered aryl ring.

II. Northern and Southern Hemisphere of the Metal Complex

The metal complex of formula (I) may be considered in two portions: a Northern Hemisphere comprising the imine nitrogen atoms and Ring A, and Southern Hemisphere, comprising the rest of the metal complex.

[Image Omitted]

Northern Hemisphere

As generally understood from the above, the Northern Hemisphere of the metal complex is of the formula (i-a):

[Image Omitted]

wherein Ring A forms an optionally substituted 5- to 6-membered ring.

In certain embodiments, Ring A forms an optionally substituted 6-membered ring of the formula (i-b):

[Image Omitted]

wherein R^4A, R^4B, R^5A, R^5B, and R^6A, R^6Bare, independently, selected from hydrogen, halogen, optionally substituted aliphatic, optionally substituted heteroaliphatic, optionally substituted aryl, optionally substituted heteroaryl, and/or, R^4Aand R^4B, and/or R^5Aand R^5B, and/or and R^6Aand R^6Bare optionally joined to form an oxo (═O) group, an oxime (═NOR^a) group, an imine (═NN(R^a)₂) group, an alkenyl (═C(R^b)₂) group, and/or a 3- to 6-membered spirocyclic ring, wherein each instance of R^aand R^bis, independently, hydrogen or optionally substituted aliphatic, wherein optionally two R^agroups or two R^bgroups are joined to form a 3- to 6-membered ring.

In certain embodiments, R^4A, R^4B, R^5A, R^5B, R^6A, and R^6Bare, independently, selected from hydrogen, optionally substituted aliphatic, optionally substituted heteroaliphatic, optionally substituted aryl, and optionally substituted heteroaryl. In certain embodiments, R^4A, R^4B, R^5A, R^5B, R^6A, and R^6Bare, independently, selected from hydrogen and optionally substituted aliphatic. In certain embodiments, R^4A, R^4B, R^5A, R^5B, R^6A, and R^6Bare, independently, selected from hydrogen and optionally substituted heteroaliphatic. In certain embodiments, R^4A, R^4B, R^5A, R^5B, R^6A, and R^6Bare, independently, selected from hydrogen and optionally substituted aryl. In certain embodiments, R^4A, R^4B, R^5A, R^5B, R^6A, and R^6Bare, independently, selected from hydrogen and optionally substituted heteroaryl. In certain embodiments, two or more of R^4A, R^4B, R^5A, R^5B, R^6A, and R^6B, are joined to form one or more aliphatic, heteroaliphatic, aromatic, or heteroaromatic rings having 3 to 8 total ring atoms.

In certain embodiments, each of R^4A, R^4B, R^5A, R^5B, R^6A, and R^6Bare hydrogen.

For example, in certain embodiments of formula (i-b), wherein each of R^4A, R^4B, R^5A, R^5B, R^6A, and R^6Bare hydrogen, Ring A forms a 6-membered ring of the formula:

[Image Omitted]

In certain embodiments, Ring A forms an optionally substituted 6-membered ring of the formula (i-c):

[Image Omitted]

wherein R^5Aand R^5Bare, independently, selected from hydrogen, halogen, optionally substituted aliphatic, optionally substituted heteroaliphatic, optionally substituted aryl, optionally substituted heteroaryl, and/or, R^5Aand R^5Bare optionally joined to form an oxo (═O) group, an oxime (═NOR^a) group, an imine (═NN(R^a)₂) group, an alkenyl (═C(R^b)₂) group, and/or a 3- to 6-membered spirocyclic ring, wherein each instance of R^aand R^bis, independently, hydrogen or optionally substituted aliphatic, wherein optionally two R^agroups or two R^bgroups are joined to form a 5- to 6-membered ring;

each instance of R¹²is selected from hydrogen, halogen, —OR, —OC(═O)R, —OC(═O)OR^c, —OC(═O)N(R^d)₂, —OSO₂R^d, —C(═O)OR^c, —C(═O)N(R^d)₂, —CN, —CNO, —NCO, —N₃, —NO2, —N(Rd)2, —N(R^d)C(═O)R^c, —N(R^d)C(═O)OR^c, —N(R^d)SO₂R^d, —SO₂R^d, —SOR^d, —SO₂N(R^d)₂, optionally substituted aliphatic, optionally substituted heteroaliphatic, optionally substituted aryl, optionally substituted heteroaryl, wherein each instance of R^cis, independently, optionally substituted aliphatic, optionally substituted heteroaliphatic, optionally substituted aryl, optionally substituted heteroaryl, and each instance of R^dis, independently, hydrogen, optionally substituted aliphatic, optionally substituted heteroaliphatic, optionally substituted aryl, optionally substituted heteroaryl; and

c is 0 to 4.

In certain embodiments, R^5Aand R^5Bare, independently, selected from hydrogen and optionally substituted aliphatic. In certain embodiments, R^5Aand R^5Bare, independently, selected from hydrogen and optionally substituted heteroaliphatic. In certain embodiments, R^5Aand R^5Bare, independently, selected from hydrogen and optionally substituted aryl. In certain embodiments, R^5Aand R^5Bare, independently, selected from hydrogen and optionally substituted heteroaryl.

However, in certain embodiments, each R^5Aand R^5Bis hydrogen.

In certain embodiments, c is 0 to 2. In certain embodiments, c is 0 to 1. In certain embodiments, c is 0. In certain embodiments, c is 1.

In certain embodiments, each instance of R¹²is, independently, selected from hydrogen and optionally substituted aliphatic. In certain embodiments, each instance of R¹²is, independently, selected from hydrogen and optionally substituted heteroaliphatic. In certain embodiments, each instance of R¹²is, independently, selected from hydrogen and optionally substituted aryl. In certain embodiments, each instance of R¹²is, independently, selected from hydrogen and optionally substituted heteroaryl.

However, in certain embodiments, each instance of R¹²is hydrogen.

In certain embodiments, Ring A forms an optionally substituted 5-membered ring of the formula (i-d):

[Image Omitted]

wherein R^4A, R^4B, R^5A, and R^5Bare, independently, selected from hydrogen, halogen, optionally substituted aliphatic, optionally substituted heteroaliphatic, optionally substituted aryl, optionally substituted heteroaryl, and/or, R^4Aand R^4Band/or R^5Aand R^5Bare optionally joined to form an oxo (═O) group, an oxime (═NOR^a) group, an imine (═NN(R^a)₂) group, an alkenyl (═C(R^b)₂) group, and/or a 3- to 6-membered spirocyclic ring, wherein each instance of R^aand R^bis, independently, hydrogen or optionally substituted aliphatic, wherein optionally two R^agroups or two R^bgroups are joined to form a 5- to 6-membered ring.

In certain embodiments, wherein R^4A, R^4B, R^5A, and R^5Bare, independently, selected from hydrogen, optionally substituted aliphatic, optionally substituted heteroaliphatic, optionally substituted aryl, optionally substituted heteroaryl, or wherein one of R^4A, R^4B, R^5Aand R^5Band one of R^4A, R^4B, R^5A, and R^5Bare optionally joined to form a 3- to 7-membered ring.

In certain embodiments, R^4A, R^4B, R^5A, and R^5Bare, independently, selected from hydrogen and optionally substituted aliphatic. In certain embodiments, R^4A, R^4B, R^5A, and R^5Bare, independently, selected from hydrogen and optionally substituted heteroaliphatic. In certain embodiments, R^4A, R^4B, R^5A, and R^5Bare, independently, selected from hydrogen and optionally substituted aryl. In certain embodiments, R^4A, R^4B, R^5A, and R^5Bare, independently, selected from hydrogen and optionally substituted heteroaryl. In certain embodiments, one of R^4A, R^4B, R^5A, and R^5Band one of R^4A, R^4B, R^5A, and R^5Bare optionally joined to form a 3- to 6-membered ring.

However, in certain embodiments, each instance of R^4A, R^4B, R^5A, and R^5Bis hydrogen.

For example, in certain embodiments of formula (i-d), wherein R^4A, R^4B, R^5A, and R^5Bare each hydrogen, Ring A forms a 5-membered ring of the formula:

[Image Omitted]

In certain embodiments of formula (i-d), wherein R^4Band R^5Bare joined to form an optionally substituted 6-membered ring, Ring A forms an optionally substituted 5-membered ring of the formula (i-f):

[Image Omitted]

wherein R^4A, R^5A, R^13A, R^13B, R^14A, R^14B, R^15A, R^15B, R^16A, R^16Bare independently, selected from hydrogen, halogen, —OR, —OC(═O)R^c, —OC(═O)OR^c, —OC(═O)N(R^d)₂, —OSO₂R^d, —C(═O)OR^c, —C(═O)N(R^d)₂, —CN, —CNO, —NCO, —N₃, —NO2, —N(Rd)2, —N(R^d)C(═O)OR^c, —N(R^d)C(═O)R^c, —N(R^d)SO₂R^d, —SO₂R^d, —SOR^d, —SO₂N(R^d)₂, optionally substituted aliphatic, optionally substituted heteroaliphatic, optionally substituted aryl, optionally substituted heteroaryl; and/or, optionally, R^13Aand R^13B, and/or R^14Aand R^14B, and/or R^15Aand R^15B, and/or R^16Aand R^16Bare optionally joined to form an oxo (═O) group, an oxime (═NOR^a) group, an imine (═NN(R^a)₂) group, an alkenyl (═C(R^b)₂) group, and/or a 3- to 6-membered spirocyclic ring, wherein each instance of R^aand R^bis, independently, hydrogen or optionally substituted aliphatic, wherein optionally two R^agroups or two R^bgroups are joined to form a 3- to 6-membered ring.

In certain embodiments, R^4A, R^5A, R^13A, R^13B, R^14A, R^14B, R^15A, R^15B, R^16A, R^16Bare, independently, selected from hydrogen, halogen, optionally substituted aliphatic, optionally substituted heteroaliphatic, optionally substituted aryl, optionally substituted heteroaryl. In certain embodiments, R^4A, R^5A, R^13A, R^13B, R^14A, R^14B, R^15A, R^15B, R^16A, R^16Bare, independently, selected from hydrogen and optionally substituted aliphatic. In certain embodiments, R^4A, R^5AR^13A, R^13B, R^14A, R^14B, R^15A, R^15B, R^16A, R^16Bare, independently, selected from hydrogen and optionally substituted heteroaliphatic. In certain embodiments, R^4A, R^5A, R^13A, R^13B, R^14A, R^14BR^15A, R^15B, R^16A, R^16Bare, independently, selected from hydrogen and optionally substituted aryl. In certain embodiments, R^4A, R^5A, R^13A, R^13B, R^14A, R^14B, R^15A, R^15B, R^16A, R^16Bare, independently, selected from hydrogen and optionally substituted heteroaryl.

However, in certain embodiments, each of R^4A, R^5A, R^13A, R^13B, R^14A, R^14B, R^15AR^15B, R^16A, R^16Bis hydrogen.

For example, in certain embodiments of formula (i-d), wherein R^4Band R^5Bare joined to form an optionally substituted 6-membered ring and each of R^4A, R^5A, R^13A, R^13B, R^14AR^14B, R^15A, R^15B, R^16A, R^16Bis hydrogen, Ring A forms an optionally substituted 5-membered ring of the formula (i-g):

[Image Omitted]

In certain embodiments of formula (i-d), wherein R^4Band R^5Bare joined to form an optionally substituted 6-membered ring, Ring A forms an optionally substituted 5-membered ring of any of the formulae (i-h) to (i-k):

[Image Omitted]

or a mixture thereof;

wherein R^4A, R^5A, R^13A, R^13B, R^14A, R^14B, R^15A, R^15B, R^16A, R^16Bare, independently, selected from hydrogen, halogen, —OR^c, —OC(═O)R^c, —OC(═O)OR^c, —OC(═O)N(R^d)₂, —OSO₂R^d, —C(═O)OR^c, —C(═O)N(R^d)₂, —CN, —CNO, —NCO, —N₃, —NO2, —N(Rd)2, —N(R^d)C(═O)OR^c, —N(R^d)C(═O)R^c, —N(R^d)SO₂R^d, —SO₂R^d, —SOR^d, —SO₂N(R^d)₂, optionally substituted aliphatic, optionally substituted heteroaliphatic, optionally substituted aryl, optionally substituted heteroaryl, and/or, R^13Aand R^13B, and/or R^14Aand R^14B, and/or R^15Aand R^15B, and/or R^16Aand R^16Bare optionally joined to form an oxo (═O) group, an oxime (═NOR^a) group, an imine (═NN(R^a)₂) group, an alkenyl (═C(R^b)₂) group, and/or a 3- to 6-membered spirocyclic ring, wherein each instance of R^aand R^bis, independently, hydrogen or optionally substituted aliphatic, wherein optionally two R^agroups or two R^bgroups are joined to form a 5- to 6-membered ring.

In certain embodiments of formulae (i-h) to (i-k), wherein R^4Band R^5Bare joined to form an optionally substituted 6-membered ring, and R^4A, R^5A, R^13A, R^13B, R^14A, R^14B, R^15A, R^15B, R^16A, R^16Bare each hydrogen, Ring A forms an optionally substituted 5-membered ring of any of the formulae (i-l) to (i-o):

[Image Omitted]

or any mixture thereof.

In certain embodiments of formula (i-d), wherein R^4Band R^5Bare joined to form an optionally substituted 6-membered ring, Ring A forms an optionally substituted 5-membered ring of the formula (i-p):

[Image Omitted]

wherein each instance of R¹⁷is, independently, selected from hydrogen, halogen, —OR^c, —OC(═O)R^c, —OC(═O)OR^c, —OC(═O)N(R^d)₂, —OSO₂R^d, —C(═O)OR^c, —C(═O)N(R^d)₂, —CN, —CNO, —NCO, —N₃, —NO₂, —N(R^d)₂, —N(R^d)C(═O)OR^c, —N(R^d)C(═O)R^c, —N(R^d)SO₂R^d, —SO₂R^d, —SOR^d, —SO₂N(R^d)₂, optionally substituted aliphatic, optionally substituted heteroaliphatic, optionally substituted aryl, optionally substituted heteroaryl, wherein each instance of R^cis, independently, optionally substituted aliphatic, optionally substituted heteroaliphatic, optionally substituted aryl, optionally substituted heteroaryl, and each instance of R^dis, independently, hydrogen, optionally substituted aliphatic, optionally substituted heteroaliphatic, optionally substituted aryl, optionally substituted heteroaryl; and/or two R¹⁷groups adjacent to each other are joined to form an optionally substituted 5- to 6-membered ring; and

d is 0 to 4.

In certain embodiments, d is 0 to 2. In certain embodiments, d is 0 to 1. In certain embodiments, d is 0. In certain embodiments, d is 1.

In certain embodiments, each instance of R¹⁷is, independently, selected from hydrogen, optionally substituted aliphatic, optionally substituted heteroaliphatic, optionally substituted aryl, and optionally substituted heteroaryl. In certain embodiments, each instance of R¹⁷is, independently, selected from hydrogen and optionally substituted aliphatic. In certain embodiments, each instance of R¹⁷is, independently, selected from hydrogen and optionally substituted heteroaliphatic. In certain embodiments, each instance of R¹⁷is, independently, selected from hydrogen and optionally substituted aryl. In certain embodiments, each instance of R¹⁷is, independently, selected from hydrogen and optionally substituted heteroaryl.

However, in certain embodiments, each instance of R¹⁷is hydrogen.

For example, in certain embodiments of formula (i-p), wherein R^4Band R^5Bare joined to form an optionally substituted 6-membered ring, Ring A forms an optionally substituted 5-membered ring of the formula (i-q):

[Image Omitted]

Southern Hemisphere

As generally understood from the above, the Southern Hemisphere of the metal complex is of the formula (ii-a):

[Image Omitted]

wherein M and X are as defined above and herein, and

each instance of R¹, R², and R³is, independently, selected from hydrogen, halogen, —OR^c, —OC(═O)R^c, —OC(═O)OR^c, —OC(═O)N(R^d)₂, —OSO₂R^d, —C(═O)OR^c, —C(═O)N(R^d)₂, —CN, —CNO, —NCO, —N₃, —NO₂, —N(R^d)₂, —N(R^d)C(═O)OR^c, —N(R^d)C(═O)R^c, —N(R^d)SO₂R^d, —SO₂R^d, —SOR^d, —SO₂N(R^d)₂, optionally substituted aliphatic, optionally substituted heteroaliphatic, optionally substituted aryl, and optionally substituted heteroaryl, and/or any of R¹and R², and/or any of R²and R³, are joined to form an optionally substituted aryl or optionally substituted heteroaryl ring.

In certain embodiments, R¹is hydrogen, halogen, optionally substituted aliphatic, optionally substituted heteroaliphatic, optionally substituted aryl, or optionally substituted heteroaryl. In certain embodiments, each instance of R¹is hydrogen. In certain embodiments, each instance of R¹is halogen. In certain embodiments, each instance of R¹is optionally substituted aliphatic. In certain embodiments, each instance of R¹is optionally substituted heteroaliphatic. In certain embodiments, each instance of R¹is optionally substituted aryl. In certain embodiments, each instance of R¹is optionally substituted heteroaryl.

In certain embodiments, each instance of R²is hydrogen, halogen, optionally substituted aliphatic, optionally substituted heteroaliphatic, optionally substituted aryl, or optionally substituted heteroaryl. In certain embodiments, each instance of R²is hydrogen. In certain embodiments, each instance of R²is halogen. In certain embodiments, each instance of R²is optionally substituted aliphatic. In certain embodiments, each instance of R²is optionally substituted heteroaliphatic. In certain embodiments, each instance of R²is optionally substituted aryl. In certain embodiments, each instance of R²is optionally substituted heteroaryl.

In certain embodiments, each instance of R³is hydrogen, halogen, optionally substituted aliphatic, optionally substituted heteroaliphatic, optionally substituted aryl, or optionally substituted heteroaryl. In certain embodiments, each instance of R³is hydrogen. In certain embodiments, each instance of R³is halogen. In certain embodiments, each instance of R³is optionally substituted aliphatic. In certain embodiments, each instance of R³is optionally substituted heteroaliphatic. In certain embodiments, each instance of R³is optionally substituted aryl. In certain embodiments, each instance of R³is optionally substituted heteroaryl.

However, in certain embodiments, R¹and R²are joined to form an optionally substituted aryl or optionally substituted heteroaryl ring. In certain embodiments, R¹and R²are joined to form an optionally substituted aryl ring. In certain embodiments, R¹and R²are joined to form an optionally substituted heteroaryl ring.

In other embodiments, R²and R³are joined to form an optionally substituted aryl or optionally substituted heteroaryl ring. In certain embodiments, R²and R³are joined to form an optionally substituted aryl ring. In certain embodiments, R²and R³are joined to form an optionally substituted heteroaryl ring.

In certain embodiments, each instance of R¹, R², and R³is, independently, selected from hydrogen, optionally substituted aliphatic, and/or any of R¹and R², and/or any of R²and R³, are joined to form an optionally substituted aryl or optionally substituted heteroaryl ring. In certain embodiments, each instance of R¹, R², and R³is, independently, selected from hydrogen and/or any of R¹and R²are joined to form an optionally substituted aryl or optionally substituted heteroaryl ring. In certain embodiments, each instance of R¹, R², and R³is, independently, selected from hydrogen and/or any of R²and R³, are joined to form an optionally substituted aryl or optionally substituted heteroaryl ring.

In certain embodiments, each instance of R¹, R², and R³is, independently, selected from hydrogen and optionally substituted aliphatic. In certain embodiments, each instance of R¹, R², and R³is, independently, selected from hydrogen and optionally substituted heteroaliphatic. In certain embodiments, each instance of R¹, R², and R³is, independently, selected from hydrogen and optionally substituted aryl. In certain embodiments, each instance of R¹, R², and R³is, independently, selected from hydrogen and optionally substituted heteroaryl.

However, in certain embodiments, each instance of R¹, R², and R³is hydrogen. In certain embodiments, each instance of R¹and R³is hydrogen. In certain embodiments, each instance of R²and R³is hydrogen. In certain embodiments, each instance of R¹and R²is hydrogen. In certain embodiments, each instance of R¹is hydrogen. In certain embodiments, each instance of R²is hydrogen. In certain embodiments, each instance of R³is hydrogen.

In certain embodiments, wherein R¹is an optionally substituted aryl moiety, the Southern Hemisphere of the metal complex is of the formula (ii-b):

[Image Omitted]

wherein M, X, R²and R³are as defined above and herein; each instance of R¹¹is, independently, selected from hydrogen, halogen, —OR, —OC(═O)R^c, —OC(═O)OR^c, —OC(═O)N(R^d)₂, —OSO₂R^d, —C(═O)OR^c, —C(═O)N(R^d)₂, —CN, —CNO, —NCO, —N₃, —NO₂, —N(R^d)₂, —N(R^d)C(═O)OR^c, —N(R^d)C(═O)R^c, —N(R^d)SO₂R^d, —SO₂R^d, —SOR^d, —SO₂N(R^d)₂, optionally substituted aliphatic, optionally substituted heteroaliphatic, optionally substituted aryl, optionally substituted heteroaryl, wherein each instance of R^cis, independently, optionally substituted aliphatic, optionally substituted heteroaliphatic, optionally substituted aryl, optionally substituted heteroaryl, and each instance of R^dis, independently, hydrogen, optionally substituted aliphatic, optionally substituted heteroaliphatic, optionally substituted aryl, optionally substituted heteroaryl; and/or two R¹¹groups adjacent to each other are joined to form an optionally substituted 5- to 6-membered ring; and b is 0 to 5.

In certain embodiments, b is 0 to 2. In certain embodiments, b is 0 to 1. In certain embodiments, b is 0. In certain embodiments, b is 1.

In certain embodiments, each instance of R¹¹is, independently, selected from hydrogen, optionally substituted aliphatic, optionally substituted heteroaliphatic, optionally substituted aryl, and optionally substituted heteroaryl, and/or two R¹¹groups adjacent to each other are joined to form an optionally substituted 5- to 6-membered ring. In certain embodiments, each instance of R¹¹is, independently, selected from hydrogen and optionally substituted aliphatic. In certain embodiments, each instance of R¹¹is, independently, selected from hydrogen, optionally substituted heteroaliphatic. In certain embodiments, each instance of R¹¹is, independently, selected from hydrogen, optionally substituted aryl. In certain embodiments, each instance of R¹¹is, independently, selected from hydrogen, optionally substituted heteroaryl.

However, in certain embodiments, each instance of R¹¹is hydrogen.

In certain embodiments, wherein one of R¹and R²are joined to form an optionally substituted aryl ring, the Southern Hemisphere of the metal complex is of the formula (ii-c):

[Image Omitted]

wherein M, X, R¹, R²and R³are, as defined above and herein; and

R⁷, R⁸, R⁹, and R¹⁰, are, independently, selected from hydrogen, halogen, —OR^c, —OC(═O)R^c, —OC(═O)OR^c, —OC(═O)N(R^d)₂, —OSO₂R^d, —C(═O)OR^c, —C(═O)N(R^d)₂, —CN, —CNO, —NCO, —N₃, —NO₂, —N(R^d)₂, —N(R^d)C(═O)OR^c, —N(R^d)C(═O)R^c, —N(R^d)SO₂R^d, —SO₂R^d, —SOR^d, —SO₂N(R^d)₂, optionally substituted aliphatic, optionally substituted heteroaliphatic, optionally substituted aryl, optionally substituted heteroaryl, wherein each instance of R^cis, independently, optionally substituted aliphatic, optionally substituted heteroaliphatic, optionally substituted aryl, optionally substituted heteroaryl, and each instance of R^dis, independently, hydrogen, optionally substituted aliphatic, optionally substituted heteroaliphatic, optionally substituted aryl, optionally substituted heteroaryl; and/or two groups selected from R⁷, R⁸, R⁹, and R¹⁰adjacent to each other are joined to form an optionally substituted 5- to 6-membered ring.

In certain embodiments, R⁷, R⁸, R⁹, and R¹⁰are, independently, selected from hydrogen, optionally substituted aliphatic, optionally substituted heteroaliphatic, optionally substituted aryl, and optionally substituted heteroaryl, and/or two groups selected from R⁷, R⁸, R⁹and R¹⁰adjacent to each other are joined to form an optionally substituted 5- to 7-membered ring. In certain embodiments, R⁷, R⁸, R⁹, and R¹⁰are, independently, selected from hydrogen and optionally substituted aliphatic. In certain embodiments, R⁷, R⁸, R⁹, and R¹⁰are, independently, selected from hydrogen and optionally substituted heteroaliphatic. In certain embodiments, R⁷, R⁸, R⁹, and R¹⁰are, independently, selected from hydrogen and optionally substituted aryl. In certain embodiments, R⁷, R⁸, R⁹and R¹⁰are, independently, selected from hydrogen and optionally substituted heteroaryl.

In certain embodiments, R⁷, R⁸, R⁹, and R¹⁰are, independently, selected from hydrogen and optionally substituted aryl. In certain embodiments, R⁷, R⁸, R⁹and R¹⁰are, independently, selected from hydrogen and optionally substituted phenyl.

In certain embodiments, R⁷, R⁸, R⁹, and R¹⁰are, independently, selected from hydrogen and optionally substituted C_1-10aliphatic. In certain embodiments, R⁷, R⁸, R⁹, and R¹⁰are, independently, selected from hydrogen and optionally substituted C_1-10alkyl. In certain embodiments, R⁷, R⁸, R⁹, and R¹⁰are, independently, selected from hydrogen and methyl, trichloromethyl, trifluoromethyl, ethyl, n-propyl, isopropyl, t-butyl, sec-butyl, iso-butyl, n-pentyl, neopentyl, amyl, trityl, adamantyl, thexyl, benzyl and cumyl.

However, in certain embodiments, each of R⁷, R⁸, R⁹, and R¹⁰are hydrogen. In certain embodiments, each of R⁸and R¹⁰are hydrogen. In certain embodiments, R⁸is hydrogen. In certain embodiments, R¹⁰is hydrogen.

For example, in certain embodiments of the formula (ii-c), wherein R⁸and R¹⁰are hydrogen, the Southern Hemisphere of the metal complex is of the formula (ii-d):

[Image Omitted]

wherein M, X, R¹, R², R³, R⁷and R⁹are, as defined above and herein.

In certain embodiments, of the formula (ii-d), wherein both R¹and R²groups are joined to form an optionally substituted aryl ring, the Southern Hemisphere of the metal complex is of the formula (ii-dd):

[Image Omitted]

wherein M, X, R³, R⁷and R⁹are, as defined above and herein.

In certain embodiments, each occurrence of R³is, independently, selected from hydrogen, halogen, optionally substituted aliphatic, optionally substituted heteroaliphatic, optionally substituted aryl, and optionally substituted heteroaryl. In certain embodiments, each occurrence of R³is hydrogen.

In certain embodiments, each occurrence of R⁷and R⁹is independently selected from hydrogen, optionally substituted aliphatic, optionally substituted heteroaliphatic, optionally substituted aryl, and optionally substituted heteroaryl.

In certain embodiments, each occurrence of R⁷and R⁹is independently selected from hydrogen, optionally substituted aliphatic and optionally substituted aryl.

In certain embodiments, each occurrence of R⁷is the same. In certain embodiments, each occurrence of R⁹is the same. In certain embodiments, each occurrence of R⁷is the same and each occurrence of R⁹is the same. In certain embodiments, R⁷and R⁹are different.

In certain embodiments, each occurrence of R⁷and R⁹is independently selected from hydrogen and optionally substituted C_1-12aliphatic. In certain embodiments, each occurrence of R⁷and R⁹is independently selected from hydrogen and optionally substituted C_1-12alkyl. In certain embodiments, each occurrence of R⁷and R⁹is independently selected from hydrogen, methyl, trichloromethyl, trifluoromethyl, ethyl, n-propyl, isopropyl, t-butyl, sec-butyl, iso-butyl, n-pentyl, neopentyl, amyl, trityl, adamantyl, thexyl, benzyl and cumyl.

In some embodiments R⁷is hydrogen. In some embodiments R⁷is methyl. In some embodiments R⁷is trichloromethyl. In some embodiments R⁷is trifluoromethyl. In some embodiments R⁷is ethyl. In some embodiments R⁷is n-propyl. In some embodiments R⁷is isopropyl. In some embodiments R⁷is t-butyl. In some embodiments R⁷is sec-butyl. In some embodiments R⁷is iso-butyl. In some embodiments R⁷is n-pentyl. In some embodiments R⁷is neopentyl. In some embodiments R⁷is amyl. In some embodiments R⁷is trityl. In some embodiments R⁷is adamantyl. In some embodiments R⁷is thexyl. In some embodiments R⁷is benzyl. In some embodiments R⁷is cumyl.

In some embodiments R⁹is hydrogen. In some embodiments R⁹is methyl. In some embodiments R⁹is trichloromethyl. In some embodiments R⁹is trifluoromethyl. In some embodiments R⁹is ethyl. In some embodiments R⁹is n-propyl. In some embodiments R⁹is isopropyl. In some embodiments R⁹is t-butyl. In some embodiments R⁹is sec-butyl. In some embodiments R⁹is iso-butyl. In some embodiments R⁹is n-pentyl. In some embodiments R⁹is neopentyl. In some embodiments R⁹is amyl. In some embodiments R⁹is trityl. In some embodiments R⁹is adamantyl. In some embodiments R⁹is thexyl. In some embodiments R⁹is benzyl. In some embodiments R⁹is cumyl.

In certain embodiments, each occurrence of R⁷and R⁹is independently selected from hydrogen and optionally substituted aryl. In certain embodiments, each occurrence of R⁷and R⁹is independently selected from hydrogen and optionally substituted phenyl.

Without wishing to be bound by any theory, it is believed that the relative sizes of the R⁷and R⁹groups influence the rate and selectivity of the polymerization reactions catalyzed by the metal complexes In certain embodiments it is advantageous for there to be a difference in the sizes of R⁷and R⁹. In certain embodiments, the group R⁷is larger than the group R⁹. However, in certain embodiments, the group R⁹is larger than the group R⁷.

The relative size of a group (e.g., in this instance, R⁷to R⁹) can be determined from the van der Waals surface and/or molecular volume as calculated for that group. For a single molecule (i.e., a molecule for which there is a path between any two atoms along covalent bonds), the van der Waals surface is a closed surface, and hence, it contains volume. This volume is called the molecular volume, or van der Waals volume, and is usually given in Å³. The straightforward way of calculating molecular volume on the computer is by numerical integration, i.e., by surrounding the van der Waals envelope with a grid of small bricks and summing up the bricks whose centers are within the van der Waals envelope of the molecule (i.e., are within a van der Waals radius from atom nucleus) (see, for example, Whitley, “Van der Waals surface graphs and molecular shape,” Journal of Mathematical Chemistry (1998) 23:377-397).

The relative size of a group can also be measured from the “A-value” for a given group. The A-value is a measure of the effective size of a given group. The “A-value” refers to the conformational energies (−G⁰values) as determined for a substituted cyclohexane and the relative axial-equatorial disposition of the substituent (see Table 1, provided below, and pages 695-697 of Eliel and Wilen, Chapter 11 entitled “Configuration and Confirmation of Cyclic Molecules” of Stereochemistry of Organic Compounds, John Wiley & Sons, Inc., New York: 1994, incorporated herein by reference). More detailed tabulations have been compiled by Hirsch, “Table of Conformational Energies”, Top. Stereochem. (1967) 1:199; Jensen and Bushweller, “Conformational Preferences in Cyclohexanes and Cyclohexenes”, Adv. Alicycl. Chem. (1971) 3:139; and Schnieder and Hoppen “Carbon-13 Nuclear Magnetic Resonance Substituent-induced Shieldings and Conformational Equilibria in Cyclohexanes”, J. Org. Chem. (1978) 43:3866; the entirety of each of which is incorporated herein by reference.

TABLE 1

Exemplary A - values

-G⁰value

Group
kcal/mol
kJ/mol

—H
~0
~0

-D
0.0006
0.025

-T
0.011
0.046

—F
0.25-0.42
1.05-1.75

—Cl
0.53-0.64
2.22-2.68

—Br
0.48-0.67
2.01-2.80

—I
0.47-0.61
1.97-2.55

—OtBu
0.75
3.14

—OPh
0.65
2.72

—OC(═O)CH₃
0.68-0.87
2.85-3.64

—OSi(CH₃)₃
0.74
3.10

—NO₂
1.1
4.8

—P(CH₃)₂
1.5-1.6
6.3-6.7

—P(Ph)₂
1.8
7.5

—C(═O)CH₃
1.02-1.52
4.27-6.36

—C(═O)OCH₃
1.2-1.3
5.0-5.4

—C(═O)OCH₂CH₃
1.1-1.2
4.6-5.0

—CN
0.2
0.84

—CCH
0.41-0.52
1.71-2.18

—CHCH₂
1.49-1.68
6.23-7.0

—CH₃(—Me)
1.74
7.28

—CH₂CH₃(—Et)
1.79
7.49

—CH(CH₃)₂(—iPr)
2.21
9.25

—C(CH₃)₃(—tBu)
4.7-4.9
19.7-20.5

—CH₂Ph
1.68
7.03

—Ph
2.8
11.71

—Si(CH₃)₃
2.5
10.5

—C₆H₁₁
2.2
9.2

—CF₃
2.4-2.5
10.0-10.5

Thus, in certain embodiments, the molecular volume of group R⁷is larger than the molecular volume of group R⁹. In certain embodiments, the molecular volume of R⁷is at least 1.2 times greater than the molecular volume of R⁹. In certain embodiments, the molecular volume of R⁷is at least 1.5 times greater than the molecular volume of R⁹. In certain embodiments, the molecular volume of R⁷is at least 1.8 times greater than the molecular volume of R⁹. In certain embodiments, the molecular volume of R⁷is at least 2 times greater than the molecular volume of R⁹. In certain embodiments, the molecular volume of R⁷is at least 2.5 times greater than the molecular volume of R⁹. In certain embodiments, the molecular volume of R⁷is at least 3 times greater than the molecular volume of R⁹.

However, in certain embodiments, the molecular volume of group R⁹is larger than the molecular volume of group R⁷. In certain embodiments, the molecular volume of R⁹is at least 1.2 times greater than the molecular volume of R⁷. In certain embodiments, the molecular volume of R⁹is at least 1.5 times greater than the molecular volume of R⁷. In certain embodiments, the molecular volume of R⁹is at least 1.8 times greater than the molecular volume of R⁷. In certain embodiments, the molecular volume of R⁹is at least 2 times greater than the molecular volume of R⁷. In certain embodiments, the molecular volume of R⁹is at least 2.5 times greater than the molecular volume of R⁷. In certain embodiments, the molecular volume of R⁹is at least 3 times greater than the molecular volume of R⁷.

In certain embodiments, the molecular volume of R⁷is greater than the molecular volume of R⁹. In certain embodiments, the A-value of R⁷is at least 1.2 times greater than the A value of R⁹. In certain embodiments, the A-value of R⁷is at least 1.5 times greater than the A value of R⁹. In certain embodiments, the A-value of R⁷is at least 1.8 times greater than the A value of R⁹. In certain embodiments, the A-value of R⁷is at least 2 times greater than the A value of R⁹. In certain embodiments, the A-value of R⁷is at least 2.5 times greater than the A value of R⁹. In certain embodiments, the A-value of R⁷is at least 3 times greater than the A value of R⁹.

However, in certain embodiments, the A-value of R⁹is greater than the A-value of R⁷. In certain embodiments, the A-value of R⁹is at least 1.2 times greater than the A value of R⁷. In certain embodiments, the A-value of R⁹is at least 1.5 times greater than the A value of R⁷. In certain embodiments, the A-value of R⁹is at least 1.8 times greater than the A value of R⁷. In certain embodiments, the A-value of R⁹is at least 2 times greater than the A value of R⁷. In certain embodiments, the A-value of R⁹is at least 2.5 times greater than the A value of R⁷. In certain embodiments, the A-value of R⁹is at least 3 times greater than the A value of R⁷.

In certain embodiments, the A-value of R⁷is greater than about 2.5 kcal/mol. In certain embodiments, the A-value of R⁷is greater than about 3 kcal/mol. In certain embodiments, the A-value of R⁷is greater than about 3.5 kcal/mol. In certain embodiments, the A-value of R⁷is greater than about 4 kcal/mol.

In certain embodiments, the A-value of R⁹is greater than about 2.5 kcal/mol. In certain embodiments, the A-value of R⁹is greater than about 3 kcal/mol. In certain embodiments, the A-value of R⁹is greater than about 3.5 kcal/mol. In certain embodiments, the A-value of R⁹is greater than about 4 kcal/mol.

In certain embodiments, the A-value of R⁹is between about 0 to about 2.5 kcal/mol. In certain embodiments, the A-value of R⁹is between about 0 to about 3 kcal/mol. In certain embodiments, the A-value of R⁹is between about 0 to about 3.5 kcal/mol. In certain embodiments, the A-value of R⁹is between about 0 to about 4 kcal/mol.

In certain embodiments, the A-value of R⁷is between about 0 to about 2.5 kcal/mol. In certain embodiments, the A-value of R⁷is between about 0 to about 3 kcal/mol. In certain embodiments, the A-value of R⁷is between about 0 to about 3.5 kcal/mol. In certain embodiments, the A-value of R⁷is between about 0 to about 4 kcal/mol.

In certain embodiments, the Southern Hemisphere of the metal complex is of the formula (ii-e):

[Image Omitted]

wherein M, X, R¹, R², R³, R⁷, R⁸, R⁹, and R¹⁰are, as defined above and herein.

In certain embodiments of formula (ii-e), wherein R³, R⁸and R¹⁰are hydrogen, the Southern Hemisphere of the metal complex is of the formula (ii-f):

[Image Omitted]

wherein M, X, R⁷and R⁹are as defined above and herein.

In certain embodiments, M is a metal selected from cobalt and chromium. In certain embodiments, M is cobalt. In certain embodiments, M is cobalt (III).

In certain embodiments, R⁷is not —C(CH₃)₂Ph. In certain embodiments, R⁷is not —[C(CH₃)₂CH₂CH₂N(Bu)₃]⁺. In certain embodiments, R⁷is not —CH(CH₂CH₃)C₆H₅. In certain embodiments, R⁷is not —C(CH₃)₂CH₂C(CH₃)₃. In certain embodiments, R⁷is not —CH(C₆H₅)CHCH₂. In certain embodiments, R⁷is not —C(CH₃)₂CH₂CH₃. In certain embodiments, R⁷is not 1-methyl-cyclohexyl. In certain embodiments, R⁷is not cyclohexyl.

In certain embodiments, R⁹is not —C(CH₃)₂C₆H₅. In certain embodiments, R⁹is not —[C(CH₃)₂CH₂CH₂N(Bu)₃]⁺. In certain embodiments, R⁹is not —C(CH₃)₂CH₂C(CH₃)₃. In certain embodiments, R⁹is not —C(CH₃)₃. In certain embodiments, R⁹is not —C(CH₃)₂CH₂CH₃. In certain embodiments, R⁹is not —CH₃. In certain embodiments, R⁹is not hydrogen.

In some embodiments, when R⁷is —C(CH₃)₂Ph, R⁹is other than —C(CH₃)₂Ph. In some embodiments, when R⁷is —[C(CH₃)₂CH₂CH₂N(Bu)₃]⁺, R⁹is other than —[C(CH₃)₂CH₂CH₂N(Bu)₃]⁺. In some embodiments, when R⁷is —CH(CH₂CH₃)C₆H₅, R⁹is other than hydrogen. In some embodiments, when R⁷is —C(CH₃)₂CH₂C(CH₃)₃, R⁹is other than —C(CH₃)₂CH₂C(CH₃)₃. In some embodiments, when R⁷is —CH(C₆H₅)CHCH₂, R⁹is other than —C(CH₃)₃. In some embodiments, when R⁷is —C(CH₃)₂CH₂CH₃, R⁹is other than —C(CH₃)₃. In some embodiments, when R⁷is —C(CH₃)₂CH₂CH₃, R⁹is other than —C(CH₃)₂CH₂CH₃. In some embodiments, when R⁷is 1-methyl-cyclohexyl, R⁹is other than —C(CH₃)₃. In some embodiments, when R⁷is 1-methyl-cyclohexyl, R⁹is other than —C(CH₃)₂CH₂CH₃. In some embodiments, when R⁷is cyclohexyl, R⁹is other than —CH₃.

In certain embodiments, the Southern Hemisphere is not selected from:

[Image Omitted]

wherein X is as defined above and herein.

Any of the above formulae (i-a) to (i-q) may be combined with any of the above formulae (ii-a) to (ii-f) to provide novel metal complexes.

For example, in certain embodiments, the present disclosure provides a metal complex of the formula (I-a):

[Image Omitted]

wherein M, X, R¹, R², R³, R^4A, R^4B, R^5A, R^5B, R^6A, and R^6Bare as defined above and herein.

In certain embodiments, the present disclosure provides a metal complex of the formula (I-b):

[Image Omitted]

wherein M, X, R¹, R²and R³are as defined above and herein.

In certain embodiments, the present disclosure provides a metal complex of the formula (I-c):

[Image Omitted]

wherein M, X, R¹, R², R³, R^5A, R^5B, R¹²and c are as defined above and herein.

In certain embodiments, the present disclosure provides a metal complex of the formula (I-d):

[Image Omitted]

wherein M, X, R¹, R², R³, R^4A, R^4B, R^5A, and R^5Bare as defined above and herein.

In certain embodiments, the present disclosure provides a metal complex of the formula (I-e):

[Image Omitted]

wherein M, X, R¹, R², R³, R^4A, R^5A, R^13A, R^13B, R^14A, R^14B, R^15A, R^15B, R^16A, R^16Bare as defined above and herein.

In certain embodiments, the present disclosure provides a metal complex of any one of the formulae (I-f) to (I-i):

[Image Omitted]

or any mixture thereof,

wherein M, X, R¹, R², R³, R^4A, R^5A, R^13A, R^13B, R^14A, R^14B, R^15A, R^15B, R^16A, R^16Bare as defined above and herein.

Where a particular enantiomer is preferred, it may, in some embodiments be provided substantially free of the corresponding enantiomer, and may also be referred to as “optically enriched.” “Optically-enriched,” as used herein, means that the compound is made up of a significantly greater proportion of one enantiomer. In certain embodiments the compound is made up of at least about 90% by weight of a preferred enantiomer. In other embodiments the compound is made up of at least about 95%, 98%, or 99% by weight of a preferred enantiomer.

Thus, in certain embodiments, the present disclosure provides an optically enriched metal complex of any one of the formulae (I-f) to (I-i). In certain embodiments, the present disclosure provides an optically enriched metal complex of formula (I-f). In certain embodiments, the present disclosure provides an optically enriched metal complex of formula (I-g). In certain embodiments, the present disclosure provides an optically enriched metal complex of formula (I-h). In certain embodiments, the present disclosure provides an optically enriched metal complex of formula (I-i).

In certain embodiments, the present disclosure provides a metal complex of the formula (I-j):

[Image Omitted]

wherein M, X, R¹, R²and R³are as defined above and herein.

In certain embodiments, the present disclosure provides a metal complex of any one of the formulae (I-k) to (I-n):

[Image Omitted]

or any mixture thereof;

wherein M, X, R¹, R²and R³are as defined above and herein.

In certain embodiments, the present disclosure provides an optically enriched metal complex of any one of the formulae (I-k) to (I-n). In certain embodiments, the present disclosure provides an optically enriched metal complex of formula (I-k). In certain embodiments, the present disclosure provides an optically enriched metal complex of formula (I-l). In certain embodiments, the present disclosure provides an optically enriched metal complex of formula (I-m). In certain embodiments, the present disclosure provides an optically enriched metal complex of formula (I-n).

In certain embodiments, the present disclosure provides a metal complex of the formula (I-o):

[Image Omitted]

wherein d, M, X, R¹, R², R³and R¹⁷are as defined above and herein.

In certain embodiments, the present disclosure provides a metal complex of the formula (I-p):

[Image Omitted]

wherein d, M, X, R¹, R²and R³are as defined above and herein.

In certain embodiments, the present disclosure provides a metal complex of the formula (I-q):

[Image Omitted]

wherein b, M, X, R¹, R², R³, R¹¹, R^4A, R^5A, R^13A, R^13B, R^14A, R^14B, R^15A, R^15B, R^16A, R^16Bare as defined above and herein.

In certain embodiments, the present disclosure provides a metal complex of the formula (I-r):

[Image Omitted]

wherein b, R¹¹, M and X are as defined above and herein.

In certain embodiments, the present disclosure provides a metal complex of the formula (I-s):

[Image Omitted]

wherein b, d, M, X, R¹, R², R³, R¹¹and R¹⁷are as defined above and herein.

In certain embodiments, the present disclosure provides a metal complex of the formula (I-t):

[Image Omitted]

wherein b, M, X, R¹, R², R³and R¹¹are as defined above and herein.

In certain embodiments, the present disclosure provides a metal complex of the formula (I-u):

[Image Omitted]

wherein M, X, R¹, R², R³, R^4A, R^5A, R⁷, R⁸, R⁹, R¹⁰, R^13A, R^13B, R^14A, R^14B, R^15A, R^15B, R^16A, R^16Bare as defined above and herein.

In certain embodiments, the present disclosure provides a metal complex of the formula (I-v):

[Image Omitted]

wherein M, X, R¹, R², R³, R⁷, R⁸, R⁹and R¹⁰are as defined above and herein.

In certain embodiments, the present disclosure provides a metal complex of the formula (I-w):

[Image Omitted]

wherein M, X, R¹, R², R³, R^4A, R^5A, R⁷, R⁹, R^13A, R^13B, R^14A, R^14B, R^15A, R^15B, R^16A, R^16Bare as defined above and herein.

In certain embodiments, the present disclosure provides a metal complex of the formula (I-x):

[Image Omitted]

wherein M, X, R¹, R², R³, R⁷and R⁹are as defined above and herein.

In certain embodiments, the present disclosure provides a metal complex of the formula (I-y):

[Image Omitted]

wherein M, X, R^4A, R^5A, R⁷, R⁸, R⁹, R¹⁰, R^13A, R^13B, R^14A, R^14B, R^15A, R^15B, R^16A, R^16Bare as defined above and herein.

In certain embodiments, the present disclosure provides a metal complex of the formula (I-z):

[Image Omitted]

wherein M, X, R^4A, R^5A, R⁷, R⁹, R^13A, R^13B, R^14A, R^14B, R^15A, R^15B, R^16A, R^16Bare as defined above and herein.

In certain embodiments, the present disclosure provides a metal complex of the formula (I-aa):

[Image Omitted]

wherein M, X, R⁷and R⁹are as defined above and herein.

In certain embodiments, the present disclosure provides a metal complex of the formulae (I-bb) to (I-ee):

[Image Omitted]

or any mixture thereof.

In certain embodiments, the present disclosure provides an optically enriched metal complex of any one of the formulae (I-bb) to (I-ee). In certain embodiments, the present disclosure provides an optically enriched metal complex of formula (I-bb). In certain embodiments, the present disclosure provides an optically enriched metal complex of formula (I-cc). In certain embodiments, the present disclosure provides an optically enriched metal complex of formula (I-dd). In certain embodiments, the present disclosure provides an optically enriched metal complex of formula (I-ee).

In certain embodiments, the present disclosure provides a metal complex of the formula (I-f):

[Image Omitted]

wherein d, M, X, R¹, R², R³, R^4A, R^5A, R⁷, R⁸, R⁹, R¹⁰and R¹⁷are as defined above and herein.

In certain embodiments, the present disclosure provides a metal complex of the formula (I-gg):

[Image Omitted]

wherein M, X, R¹, R², R³, R⁷, R⁸, R⁹and R¹⁰are as defined above and herein.

In certain embodiments, the present disclosure provides a metal complex of the formula (I-hh):

[Image Omitted]

wherein d, M, X, R¹, R², R³, R⁷, R⁹and R¹⁷are as defined above and herein.

In certain embodiments, the present disclosure provides a metal complex of the formula (I-ii):

[Image Omitted]

wherein M, X, R¹, R², R³, R⁷and R⁹are as defined above and herein.

In certain embodiments, the present disclosure provides a metal complex of the formula (I-jj):

[Image Omitted]

wherein d, M, X, R^4A, R^5A, R⁷, R⁸, R⁹, R¹⁰and R¹⁷are as defined above and herein.

In certain embodiments, the present disclosure provides a metal complex of the formula (I-kk):

[Image Omitted]

wherein d, M, X, R⁷, R⁹and R¹⁷are as defined above and herein.

In certain embodiments, the present disclosure provides a metal complex of the formula (I-ll):

[Image Omitted]

wherein M, X, R⁷and R⁹are as defined above and herein.

In certain embodiments, the present disclosure provides a metal complex of the formula (I-mm):

[Image Omitted]

wherein M, X, Ring A, R³, R⁷and R⁹are as defined above and herein.

In certain embodiments, the present disclosure provides a metal complex of the formula (I-nn):

[Image Omitted]

wherein M, X, Ring A, R¹, R², R³, R⁷and R⁹are as defined above and herein.

In certain embodiments, the present disclosure provides a metal complex of the formula (I-oo):

[Image Omitted]

wherein M, X, R⁷, R⁹, R^4A, R^4B, R^5A, R^5B, and R^6A, R^6Bare as defined above and herein.

III. Exemplary Metal Complexes

In certain embodiments, the metal complex is selected from any one of the following, wherein X is absent or is a nucleophilic ligand:

[Image Omitted]

In certain embodiments, the metal complex is selected from any one of the following, wherein X is absent or is a nucleophilic ligand:

[Image Omitted]