Unexpected formation of a fused double cycle trinuclear gold() complex supported by -phenyl metallated aryl-diphosphine ligands and strong aurophilic interactions

The first homoleptic trinuclear arylgold( i ) complex, [Au 3 (L′) 2 ](NO 3 ) ( 3 ), based on an ortho -phenyl metallated aryl-diphosphine ligand (L′ = o -C 6 H 4 PPh(C 15 H 10 O)PPh 2 ), has been obtained through a new thermolytic reaction of the corresponding diauracycle, [Au 2 (L) 2 ](NO 3 ) 2 (L = xantphos). The formation of 3 involves activation of the ortho -phenyl C-H bond of the xantphos ligands. The presence of Au-C bonds in this new gold-diphosphine cluster is not its only remarkable feature, since it also displays two 12-membered rings fused together and a linear {Au 3 } chain with aurophilic interactions. Complex 3 exhibits strong sky-blue luminescence that can be assigned to a triplet metal-metal ( 3 MM) transition partially mixed with a ligand-to-metal-metal charge transfer ( 3 LMMCT) transition related to the aurophilic bonding. This [Au 3 (L′) 2 ] + triauracycle also shows AIEE-activity, and is a selective luminescent chemosensor for metal ions. The first homoleptic trinuclear arylgold( i ) complex, [Au 3 (L′) 2 ](NO 3 ) ( 3 ), has been obtained through a new thermolytic reaction of [Au 2 (L) 2 ](NO 3 ) 2 ( 1 ).