Synthesis and structural studies of some gold(I) complexes containing selenoureato ligands

N,N-Diethyl-N′-4-nitrobenzoylselenourea (HLSe) reacts with the mono- and dinuclear phosphine gold(I) chloro complexes [AuCl(PR3)] (R=Ph, o-tol, Et) and [Au2Cl2(μ-P-P)] (P-P=dppm, dppe, dppp, dppb, dppf) in the presence of base to give gold(I) phosphine selenoureato complexes [Au(LSe)(PR3)] [R=Ph (1), o-tol (2), Et (3)], [Au2(LSe)2(μ-P-P)] [P-P=dppm (4), dppe (5), dppp (6), dppb (7), dppf (8)] in excellent yields. The compounds were fully characterised by spectroscopic methods and, in the case of compounds 1, 5 and 8, by single crystal X-ray diffraction. The compounds consist of a gold atom bound in linear fashion to the phosphine ligand and the selenium atom from the deprotonated acylselenourea. These complexes thus represent the first examples of acylselenoureato metal compounds in which the ligands do not adopt the typical O,Se chelating mode but rather coordinate to the metal only through the selenium atom.