Gold(I) Complexes Containing Phosphanyl- and Arsanylborane Ligands

Abstract

The structural and photophysical properties of a series of new AuI compounds have been studied. The reactions of AuCl(tht) with the phosphanyl- and arsanylboranes RR′EBH2NMe3 (E=P, As; R=H, Ph; R′=H, Ph, tBu) afford the complexes [AuCl(RR′EBH2NMe3)]. In the solid state, [AuCl(H2PBH2NMe3)]2 (2 a) is a dimer showing unsupported intermolecular aurophilic interactions with short Au⋅⋅⋅Au distances. In contrast, [AuCl(H2AsBH2NMe3)]n (2 b) aggregates to form 1D chains. Organic substituents on the pnictogen atoms lead to discrete molecules in [AuCl(RR′PBH2NMe3)] (2 c: R=H, R′=tBu; 2 d: R=R′=Ph). To increase the aurophilicity, the ionic homoleptic complexes [Au(RR′EBH2NMe3)2][AlCl4] (3 a–d) have been synthesized, for which 3 a,b form chains in the solid state and exhibit luminescence. The emissions show a drastic redshift with temperature decrease, correlating with decreasing Au⋅⋅⋅Au distances. DFT calculations provide insight into the bonding situation of the products.