Complexation of zinc tetraphenylporphyrin by adsorbed poly(4-vinylpyridine): equilibrium studies

Equilibrium constants have been measured for the reversible complexation of zinc tetraphenylporphyrin with poly(4-vinylpyridine) both in solution and in a system in which the polymer had been adsorbed onto fused silica. The complexation of the porphyrin with adsorbed polymer follows the behavior expected for reversible complexation at independent sites (so-called Langmuir-type isotherm). The equilibrium constant for complexation to the polymer in solution is somewhat smaller than that for complexation to pyridine, but the equivalent quantity for complexation to the polymer adsorbed onto silica is very large. 7 figures.