Group 6 transition metal carbonyl complexes with chalcogen-bridged diarsenic(III) ligands

Abstract

The neutral complexes [Cr(CO)₄(Ph₂AsOAsPh₂)] 1, [Mo(CO)₄(Ph₂AsOAsPh₂)₂] 2, [Cr(CO)₄(Ph₂AsSAsPh₂)] 3, [Mo(CO)₄(Ph₂AsSAsPh₂)₂] 4, [Cr(CO)₅(Ph₂AsOAsPh₂)] 5 and [Cr(CO)₅(Ph₂AsSAsPh₂)] 6 have been prepared. The crystal structures of compounds 1–5 were determined. The diarsenic ligand in 2, 4, and 5 is monodentate and in 1 and 3 the ligand is bidentate. The crystal structure of the ligand Ph₂AsOAsPh₂ was redetermined and the As–O–As angle found to be 115.98(17)°, significantly less than the value originally reported. Calculations, using density functional theory, assist discussion of the steric and electronic factors influencing the choice of binding mode.