Di-, tri-, pseudo-di- and pseudo-tetra-acetylenic polymers of platinum: Synthesis, characterization and optical spectra

Reactions of Me 3 Sn-CC-(CC-) m -CC-SnMe 3 ( m = 0, 1) ( 1 , 2 ), Me 3 Sn-(CC) m - p -C 6 H 4 -(CC) m -SnMe 3 ( m = 1, 2) ( 3 , 4 ) with the platinum metal halide complexes, [Pt(X n Bu 3 ) 2 Cl 2 ] (where X = P ( 5 ), As ( 6 )) afford high molecular weight polymeric species, [-Pt(X n Bu 3 ) 2 -CC-(CC) m -CC-] n ( 7-10 ), and [-Pt(P n Bu 3 ) 2 -(CC) m - p -C 6 H 4 -(CC) m -] n ( 11, 12 ) in excellent yields. Investigations of the optical absorption and photoluminescence spectra of these complexes show extended π-electron conjugation through the metal sites on the chain, with a lower π-π* energy gap for triacetylenic than for the diacetylenic polymeric complexes. Well-resolved vibronic structure associated with the -CC- stretching frequency is observed for both absorption and emission, indicating strong electron-phonon coupling for the di- and triacetylenic polymers.