Synthesis, characterization, self-assembly, gelation, morphology and computational studies of alkynylgold(III) complexes of 2,6-bis(benzimidazol-2'- yl)pyridine derivatives

A novel class of alkynylgold(III) complexes of the dianionic ligands derived from 2,6-bis(benzimidazol-2'-yl)pyridine (H₂bzimpy) derivatives has been synthesized and characterized. The structure of one of the complexes has also been determined by X-ray crystallography. Electronic absorption studies showed low-energy absorption bands at 378-466 nm, which are tentatively assigned as metal-perturbed π-π* intraligand transitions of the bzimpy^2- ligands. A computational study has been performed to provide further insights into the nature of the electronic transitions for this class of complexes. One of the complexes has been found to show gelation properties, driven by π-π and hydrophobic-hydrophobic interactions. This complex exhibited concentration- and temperature-dependent ¹H NMR spectra. The morphology of the gel has been characterized by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Copyright © 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.