Dipyridophenazine as electronic tunable ligands for the palladium-catalyzed synthesis of polyketones
A series of Pd - methyl complexes, 1a - 6a, with 11-R-dipyrido[3,2-a: 2′,3′-c]phenazine ligands (dppz-R) being electronically modified with an R sustituent, efficiently catalyze CO/ styrene copolymerization under mild conditions. Increased catalytic activity is observed on increasing the electron-donating character of the remote R substituent in the order R = NO 2 3 2.