MONONUCLEAR, DINUCLEAR AND TRINUCLEAR GOLD(I) COMPLEXES OF NEW PHOSPHINO-SUBSTITUTED AMIDES - INITIAL STEPS TO CHLOROGOLD(I)DIPHENYLPHOSPHINO-TERMINATED DENDRIMERS

The amides MeNH-CO-square-PPh(2) (square = CH2 (2a); C6H4 (2b)) have been prepared from methylamine and alpha-diphenylphosphinoacetic acid (1a) or p-diphenylphosphino-benzoic acid (1b), respectively, using EDC (N'-(3-dimethylaminopropyl)-N-ethylcarbodiimide hydrochloride) as a coupling agent. The dendritic, multifunctional species MeN(CH2CH2CH2NH-CO-square-PPh(2))(2) (5a, 5b) and N(CH2CH2NH-CO-C6H4-PPh(2))(3) (8) have been obtained following the same procedure. Treatment of the diphenylphosphino-terminated compounds with equivalent amounts of (dimethylsulfide)gold(I) chloride afforded the corresponding mono-, di- and trinuclear gold(I) complexes 3a,b, 6a,b and 9 with chain-end (diphenylphosphino)gold(I) chloride groups (-PPh(2)AuCl) in excellent yields as stable colorless solids. X-ray structure analyses have been performed for MeNH-CO-C6H4-PPh(2) (2b) (orthorhombic, space group Pna2(1)), N(CH2CH2NH-CO-C6H4-PPh(2))(3) (8) (triclinic, space group P $($) over bar$$ 1) and MeNH-CO-CH2-PPh(2)AuCl (3a) (orthorhombic, space group P2(1)2(1)2(1)). The conformation of the molecules and their packing can be rationalized on the basis of both inter- and intramolecular NH ... O hydrogen bonds, which in this case exclude intermolecular Au-1 ... An(1) contacts between the MeNH-CO-CH2-PPh(2)AuCl molecules.