Aurophilicity and Photoluminescence of (6-Diphenylpnicogenoacenaphth-5-yl)gold Compounds

Abstract

The organotin precursors 6-Br-Ace-5-SnBu3 (6, Ace = acenaphthyl) and 6-Ph2E-Ace-5-SnBu3 (7a: E = P; 7b: E = As; 7c: E = Sb) were prepared and used for the synthesis of organogold complexes, namely, the homodinuclear arylgold(I) species (6-Ph2E-Ace-5-Au)2 (8a: E = P; 8b: E = As; 8c: E = Sb), arylgold(III) dichloride 6-Ph2P-Ace-5-AuCl2 (9), diarylgold(III) chloride [trans-(6-Ph2P-Ace-5-)2Au]Cl ([10]Cl), as well as the heterodinuclear gold complexes 6-Ph2P(AuX)-Ace-5-Au(AsPh3) (11a: X = Cl; 11b: X = Br). Compounds 8a - 8c, 11a, and 11b show significant aurophilic interactions, which are related to their photoluminescence upon exposure to UV light. In the solid state, 11a and 11b show green-yellow emission, whereas 8a - 8c are non-emissive. In solution under an argon atmosphere, all five compounds 8a - 8c as well as 11a and 11b show green-yellow emission. The organogold complexes were characterized by multinuclear NMR spectroscopy, photoluminescence spectroscopy, single-crystal X-ray crystallography, as well as (TD-)DFT calculations including real-space bond indicators derived from atoms-in-molecules (AIM), the electron localization indicator (ELI-D), and the non-covalent interaction (NCI) index.