Ligands designed to provide highly active catalyst complexes

摘要

A series of ligands with site specific electron donating substituents that form a catalyst complex with a transition metal and are suitable for catalysis of atom transfer radical reactions, including ATRP are described. Faster catalysis rates were observed allowing for low catalyst concentrations and linear increases in molecular weight with monomer conversion, and narrow molecular weight distributions. Cyclic voltammetry revealed that increasing the strength and number of conjugated electron donating groups resulted in more stable complexes and larger ATRP equilibrium constants.

主权项

1. A catalyst complex for a redox-based atom transfer radical addition reaction, an atom transfer radical coupling reaction or a controlled radical polymerization reaction, the catalyst complex comprising:
a transition metal; and a ligand comprising from 2 to 6 heteroatom containing groups that bond to or chelate with a transition metal, wherein at least one of the heteroatom containing groups comprises a structure selected from a nitrogen containing heteroaromatic ring, wherein the heteroaromatic ring further comprises one or more electron donating substituents; wherein the ligand has a structure selected from the group consisting of (4-methoxy-3,5-dimethyl-pyridin-2-ylmethyl)-bis(pyridin-2-ylmethyl)-amine (TPMA*-1), bis(4-methoxy-3,5-dimethyl-pyridin-2-ylmethyl)-pyridin-2-ylmethyl-amine (TPMA*-2), tris[(4-methoxy-3,5-dimethyl)-pyrid-2-ylmethyl]amine (TPMA*-3), (4-methoxy-pyridin-2-ylmethyl)-bis(pyridin-2-ylmethyl)-amine (TPMA-OMe), bis(4-methoxy-pyridin-2-ylmethyl)-pyridin-2-ylmethyl-amine (TPMA-OMe-2), tris((4-methoxy)-pyridin-2-yl)methy)l-amine (TPMA-OMe-3), (4-(N,N-dimethylamino)-pyridin-2-ylmethyl)-bis(pyridin-2-ylmethyl)-amine (TPMA-NMe2), bis(4-(N,N-dimethylamino)-pyridin-2-ylmethyl)-pyridin-2-ylmethyl-amine (TPMA-NMe2-2), tris(4-(N,N-dimethylamino)-pyridin-2-yl)methyl)-amine (TPMA-NMe2-3), bis((4-methoxy-3,5-dimethyl)-pyrid-2-ylmethyl)-octadecylamine (BPMODA*), N,N′-bis((4-methoxy-3,5-dimethyl)-pyrid-2-yl)methyl-octadecyl)ethylenediamine (BPED*-OD), N,N,N′,N′-tetra[(4-methoxy-3,5-dimethyl)-pyrid-2-yl)methyl]ethylenediamine (TPEN*), N-methyl-N,N′,N′-tris[(4-methoxy-3,5-dimethyl)-pyrid-2-yl)methyl]ethylenediamine (TPMEN*), N,N-dimethyl-N′,N′-bis(2-hydroxy-3,5-dimethylbenzyl)ethylenediamine, and 2,4-dimethyl-6-bis(2-(diethylamino)-ethyl)aminomethylphenol; and wherein the ligand forms the catalyst complex with the transition metal.