Coordination ability of poly(vinylene-arsine)s towards transition metal ions

Coordinations of poly(vinylene-arsine)s (1) towards transition metal ions were carried out to estimate the coordination ability of phenyl-substituted poly(vinylene-arsine) (1a) and methyl-substituted poly(vinylene-arsine) (1b). No 1a-Co complex was obtained upon addition of an acetone solution of 1a to an acetone solution of cobalt (II) chloride hexahydrate. On the other hand, 1b-Co complexes were obtained in the reactions at different cobalt salt-1b feed ratios. As in the usual case, the bivalent complexes of the reaction run corresponding to the feed ratio of 1:1 [CoCl₂]/[repeating unit of 1b] oxidized readily in air to give very stable complexes of trivalent cobalt. On the other hand, the bivalent complexes of the reaction runs corresponding to the feed ratios of 1:4 and 1:10 both exhibited unusual stability against air oxidation owing to the higher concentration of 1b in the reaction mixture. Reactions of 1 and bis(2,2'-bipyridyl)ruthenium(II) dichloride also provided polymer complexes. In all the cases, 1b had higher coordination property than 1a due to its lower steric hindrance.