Synthesis, characterization, electrochemistry, and photophysical studies of triarylamine-containing zinc(ii) diimine bis-thiolate complexes

Abstract

A series of triarylamine-containing Zn(II) diimine bis-thiolate complexes, [Zn(N^N)(SC₆H₄Me-4)₂] (N^N = 5,5′-bis(N,N-diaryl-4-[ethen-1-yl]-aniline)-2,2′-bipyridine or 1,10-bis(N,N-diaryl-4-[ethen-1-yl]-aniline)-phenanthroline), were synthesized and characterized by ¹H NMR spectroscopy, FAB mass spectrometry and satisfactory elemental analysis. Some of the complexes exhibited intense emissions in dichloromethane solution with maxima at 611–685 nm, which originated from both ligand-to-ligand charge transfer [p_π(SR⁻) → π*(diimine)] and intraligand charge transfer [π(triarylamine) → π*(diimine)] excited states. The emission maxima were tuned by variation of the donor or acceptor moieties. Thin film emission studies were also carried out on the complexes. All these complexes showed similar Gaussian-shaped emission bands with emission energies similar to those observed in dichloromethane solution at 298 K. In addition, the emission bands displayed concentration-dependent properties in thin-film emission studies.