POLARIZABLE STILBAZOLE-BASED ORGANOMETALLIC COMPLEXES AND POLYMERS

Oxidative addition reactions of trans-4'-bromo-4-stilbazole (1) to Pd(PMe3)4, Pd(PEt3)4, and Pd(PiPr3)3 yield the corresponding Pd(II) complexes (5). The quaternary complexes (6 and 7) are obtained by methylation and protonation of 5. Bromide abstraction from 5 leads to the charged polymers 9. Comparison of the spectroscopic properties (UV, IR, NMR) of these complexes, as well as those of the gold complex 4, with those of the parent organic compounds indicates that there is considerable metal participation in the conjugated systems. The oscillator strength (f) for the pi-pi* transition of the various compounds has been determined. The Pd and Au complexes have considerably higher f values than the parent bromostilbazoles, while palladium complexes exhibit a lower energy pi-pi* transition than the latter. The nature of the phosphine ligand in the palladium complex has a minor effect on conjugation.