Gold complexes with selenium ligands. Part 7. Synthesis and crystal structures of oligonuclear gold(I)-selenolate complexes

Abstract

Cationic and neutral Oligonuclear organophosphinegold(I) complexes with organic selenolate ligands SeR [R = Ph, CH₂Ph, C₆H₄NH₂– 4, C₆H₄Cl – 4 or C₁₀H₇, (naphthyl)] have been prepared and characterized by spectroscopic methods. Additionally, X-ray crystal structure analyses have been performed for [(AuPPh₃)₂(SeCH₂Ph)]SbF₆, the mixed cationic-neutral complex [(AuPPh₃)₂(SeC₁₀H₇)]SbF₆·[Au(PPh₃)(SeC₁₀H₇)] and for [(AuSePh)₂(dppe)][dppe = 1,2-bis(diphenylphosphino)ethane]. The Au–Se bond lengths lie in the range 2.41 2 Å(neutral complexes) to 2.465 Å(cationic complexes). All crystal structures show distortions of the co-ordination geometry at selenium and reveal short Au ⋯ Au contacts. The molecular structure of [(AuPPh₃)₂(SeCH₂Ph)]SbF₆ represents the first example of a cationic alkylselenolate-gold complex. The complex [(AuPPh₃)₂(SeC₁₀H₇)]SbF₆·[Au(PPh₃)(SeC₁₀H₇)] exhibits an unexpected structure: the cationic and the corresponding neutral selenolate complex are linked by intermolecular Au ⋯ Au interactions, thus forming a trinuclear selenolate complex. The complex [(AuSePh)₂(dppe)] is the first structurally characterized gold-organoselenolate complex with a bridging diphosphine ligand.