Transition metal mediated routes to poly(arylphosphine)s: investigation of novel phosphorus containing conjugated polymers

Poly(aryi-P-alkylphosphine)s were prepared via palladium and nickel mediated coupling and the spectral and electrochemical properties of the polymers were investigated. Palladium catalyzed carbon-phosphorus bond formation was used for the preparation of poly(.p-phenylene-P-alkylphoshpine)s (1a-b) via two routes. Low molecular weight polymers (1000-3000) were obtained by the condensation polymerization of 1,4-diiodobenzene with primary alkylphosphines. Higher molecular weight polymers (1000-14 000) were obtained via polymerization of p-bromophenylalkylphosphines (2a-b). Poly(4,4'-diphenyl-P-2,4,4-trimethylpentylphosphine (TMPPH2)) (4b) was also prepared via two routes, the palladium catalyzed cross-coupling of 4,4'-diiodobiphenyl with primary alkylphosphines and the nickel mediated homo-coupling of bis-p-bromophenylalkylphosphines. The molecular weight of 4b was low (1000-3000) via both routes due to poor solubility. The electronic properties of polymers 1a-b were investigated with UV-vis-NIR spectroscopy and cyclic voltammetry and suggest a degree of electronic delocalization along the polymer backbone through phosphorus. (C) 2002 Elsevier Science B.V. All rights reserved.