The reactivity of [Pt2(μ-S)2(PPh3)4] towards difunctional chloroacetamide alkylating agents: Formation of cyclized or bridged products

Abstract

The reactions of [Pt 2 (-S) 2 (PPh 3) 4 ] towards some bis(chloroacetamide) alkylating agents have been investigated. Reaction with one mole equivalent of the hydrazine-derived compound ClCH 2 C(O)NHNHC(O)CH 2 Cl led to the cyclised product [Pt 2 {SCH 2 C(O)NHNHC(O)CH 2 S}(PPh 3) 4 ] 2+ which showed two different PPh 3 environments in the 31 P{ 1 H} NMR spectrum, as a result of non-fluxional behaviour of the dithiolate ligand in solution. Reactions of [Pt 2 (-S) 2 (PPh 3) 4 ] with the ortho and para isomers of the phenylenediamine-derived bis(chloroacetamides) ClCH 2 C(O)NHC 6 H 4 NHC(O)CH 2 Cl gave tetrametallic complexes containing two {Pt 2 S 2 } moieties spanned by the CH 2 C(O)NHC 6 H 4 NHC(O)CH 2 group. Both the ortho and para isomers were crystallographically characterised; in the ortho isomer there is intramolecular C=O•••H-N and S•••H-N hydrogen bonding involving the two amide groups.