Zero-field splitting of the ligand-ligand charge-transfer emitting manifold of zinc(II) complexes

Abstract

Zero-field splittings of the emitting ligand-ligand charge-transfer (LLCT) states were observed for Zn(4-CH{sub 3}O-PhS){sub 2}(phen) and Zn(4-Cl-PhS){sub 2}(phen). The spin-axis-independent zero-field-splitting parameters D{sup *} are 1.63 GHz for Zn(4-CH{sub 3}O-PhS){sub 2}(phen) and 2.25 GHz for Zn(4-Cl-PhS){sub 2}(phen). The measurements confirm the triplet nature of the emitting state at low temperature. The calculated splittings due to spin dipole-spin dipole interaction are much smaller than the experimental values. Mixing with the phenanthroline-localized {sup 3}{sub {pi}{pi}}{sup *} state is suggested to account for the large measured values of D{sup *}.