Aurophilic Interactions in Three-Coordinate Gold(I) Complexes with C-Clamp-like Structures

Compounds containing three-coordinate gold-(I) centers that engage in aurophilic interactions have been obtained by using bridging diphosphines. Colorless crystals of [(μ-dppm)-{Au-(bipy)}2]-(PF6)2 (1) and [(μ-dppe)-{Au-(bipy)}2]-(BF4)2 (2) (where dppm is bis-(diphenylphosphino)-methane), dppe is 1,2-bis-(diphenylphosphino)-ethane and bipy is 2,2' bipyridine have been obtained by a one pot method combining dppm (or dppe) with (tht)-AuCl (tht is tetrahydrothiophene), bipy, and ammonium hexafluorophosphate in chloroform. The cations in [(μ-dppm)-{Au-(bipy)}2]-(PF6)2 (1) and [(μ-dppe)-{Au-(bipy)}2]-(BF4)2 (2) have c-clamp-like structures with Au-Au bond lengths of 3.0903(6) and 3.249(1) Å, respectively. Unlike the situation in many two-coordinate gold-(I) complexes, where aurophilic interactions induce luminescence, crystals of complexes (1) and (2) are not luminescent at room temperature or at 90 K.