Polymerization of coordinated monomers. XIII. Binding in the ternary molecular complex composed of γ‐crotonolactone, styrene, and stannic chloride

Abstract

The time‐averaged orientation of the styrene molecule in the ternary molecular complex composed of stannic chloride, γ‐crotonolactone, and styrene is determined by use of 1H‐chemical shifts of the nonequivalent protons of the γ‐crotonolactone. The chemical shift change for each of the various protons of the γ‐crotonolactone on the ternary molecular complex formation can be represented by the anisotropic shielding effect of the benzene ring of one oriented styrene molecule. This fact indicates that the ternary molecular complex has a definite time‐averaged conformation, though the “complexing” styrene molecule exchanges between in the oriented state and in the free state more rapidly than the time scale of the 1H‐NMR spectrometry. The magnitudes of the Coulomb, induction, dispersion, charge‐transfer, and exchange‐repulsion energies between the γ‐crotonolactone and the styrene in the ternary molecular complex are estimated by use of the result of the extended Hückel calculation and that of absorption spectrometry. The Coulomb and dispersion forces between the carboryl group of the coordinated γ‐crotonolactone and the benzene ring of the styrene function mainly in the ternary molecular complex formation. Both the induction force and the charge‐transfer force make a small contribution to the ternary molecular complex formation.