Tris(6-diphenylphosphinoacenaphth-5-yl)gallium: Z‑Type Ligand and Transmetalation Reagent

The
reaction of 5-diphenylphosphinoacenaphth-6-yllithium, 5-Ph2P-Ace-6-Li, with GaCl3 afforded (6-Ph2P-Ace-5-)3Ga (1), which was studied for its
potential to serve as a Z-type ligand. Indeed, the reaction of 1 with Ni­(COD)2 and (Ph3P)4Pd yielded complexes 1·Ni and 1·Pd, comprising Ni/Pd → Ga donor–acceptor
bonds. The reaction of 1 with CuCl, most likely proceeding
through the formation of the transient complex 1·CuCl,
produced a mixture of (6-Ph2P-Ace-5-)2GaCl (2) and the tetranuclear copper­(I) cluster (6-Ph2P-Ace-5-Cu)4 (3) showing aggregation-induced
phosphorescence. When exposed to moist air, the mixture of 2 and 3 gave rise to C–C cross-coupling and the
formation of [(6-Ph2P-Ace-5-)2]­CuCl (4). The Z-type bonding of 1·Ni, 1·Pd,
and 1·CuCl as well as the photoluminescence of 3 were investigated by a detailed density functional theory
(DFT) study including real-space and orbital-based approaches.