Mono-, di and trinuclear gold(I) complexes of new phosphino-substitutedamides: initial steps to chlorogold(I)diphenylphosphino-terminated dendrimers

Article abstract of DOI:10.1016/0020-1693(95)90067-G

The amides MeNH-CO-.box.PPh2 (.box. = CH2 (2a); C6H4 (2b)) have been prepared from methylamine and α-diphenylphosphinoacetic acid (1a) orp-diphenylphosphino-benzoic acid (1b), respectively, using EDC (N'-(3-dimethylaminopropyl)-N-ethylcarbodiimide hydrochloride) as a coupling agent. The dendritic, multifunctional species MeN(CH2CH2CH2NH-CO-.box.-PPh2)2 (5a, 5b) and N(CH2CH2NH-CO-C6H4-PPh2)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 (-PPh2AuCl) in excellent yields as stable colorless solids. X-ray structure analyses have been performed for MeBH-CO-C6H4PPh2 (2b) (orthorhombic, space group Pna2(1)), N(CH2CH2NH-CO-C6H4-PPh2)3 (8) (triclinic, space group P1-) and MeNH-CO-CH2-PPh2AuCl (3a) (orthorhombic, space group P212121). 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(I)...Au(I) contacts between MeNH-CO-CH2-PPh2AuCl molecules.