Catalysts for polycarbonate production

A unimolecular metal complex of formula I:

• wherein:
• M is a metal atom;
• X is optionally present and when present is an anion;
• comprises a ligand having the formula:
• wherein each Rd is independently selected from the group consisting of:
• (Z)m, hydrogen, halogen, —OR, NR2, —SR, —CN, —NO2, —SO2R, —SOR, —SO2NR2, —CNO, —CO2R, —CON(R)2, —OC(O)NR2, —OC(O)OR, —NRSO2R, —NCO, —N3, —SiR3, an optionally substituted radical independently selected from the group consisting of C1-20 aliphatic, C1-20 heteroaliphatic, phenyl, a 3- to 8-membered saturated or partially unsaturated monocyclic carbocycle, a 7- to 14-membered saturated, partially unsaturated or aromatic polycyclic carbocycle, a 5- to 6-membered monocyclic heteroaryl ring having 1-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur, a 3- to 8-membered saturated or partially unsaturated heterocyclic ring having 1-3 heteroatoms independently selected from nitrogen, oxygen, or sulfur, a 6- to 12-membered polycyclic saturated or partially unsaturated heterocycle having 1-5 heteroatoms independently selected from nitrogen, oxygen, or sulfur, and an 8- to 10-membered bicyclic heteroaryl ring having 1-5 heteroatoms independently selected from nitrogen, oxygen, or sulfur, where two or more Rd groups may be taken together to form one or more optionally substituted rings optionally containing one or more heteroatoms;
• each R is independently hydrogen or an optionally substituted radical selected the group consisting of acyl, C1-20 aliphatic, C1-20 heteroaliphatic, phenyl, a 3- to 8-membered saturated or partially unsaturated monocyclic carbocycle, a 7- to 14-membered saturated, partially unsaturated or aromatic polycyclic carbocycle, a 5- to 6-membered monocyclic heteroaryl ring having 1-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur, a 3- to 8-membered saturated or partially unsaturated heterocyclic ring having 1-3 heteroatoms independently selected from nitrogen, oxygen, or sulfur, a 6- to 12-membered polycyclic saturated or partially unsaturated heterocycle having 1-5 heteroatoms independently selected from nitrogen, oxygen, or sulfur, or an 8- to 10-membered bicyclic heteroaryl ring having 1-5 heteroatoms independently selected from nitrogen, oxygen, or sulfur, an oxygen protecting group, and a nitrogen protecting group, where two R groups on the same nitrogen atom can optionally be taken together to form an optionally substituted 3- to 7-membered ring;
• each n is independently an integer 1 to 4 inclusive;
• each Rz is optionally present and when present is independently alkyl or a hydroxyl protecting group, wherein the ligand has zero or one Rz groups;
• and
• (Z)m represents a tethered activating moiety covalently bonded to the ligand at any suitable position, wherein each represents a linker moiety, each Z independently comprises a nitrogen or phosphorous containing functional group, and m is an integer of one or greater indicating how many such nitrogen or phosphorous containing functional groups are attached to a given linker.