Syntheses and characterization of heterobimetallic complexes (dppf)Pt(dithiolate) (dppf: bis(diphenylphosphino)ferrocene); X-ray crystal structures of (dppf)PtL where L = dmit, phdt and i-mnt

Abstract Heterobimetallic complexes of the type (dppf)PtL (dppf=1,1′-bis(diphenylphosphino)ferrocene; L=dmit (1,3-dithiole-2-thione-4,5-dithiolate), dddt (5,6-dihydro-1,4-dithiin-2,3-dithiolate), phdt (6-hydro-5-phenyl-1,4-dithiin-2,3-dithiolate), dphdt (5,6-diphenyl-1,4-dithiin-2,3-dithiolate), mtdt (1,2-bis(methylthio)ethylene-1,2-dithiolate), i -mnt (2,2-dicyano-1,1-ethylenedithiolate)) have been synthesized and studied by a high-resolution FAB-MS, cyclic voltammetry and 31 P NMR. (Dppf)Pt( i -mnt) exhibits one reversible redox peak at E 1/2 =1.225 V and a strong Pt–P coupling constant ( J Pt–P =3237 Hz) due to the electron-accepting property of i -mnt ligand. On the contrary, (dppf)Pt(mtdt) shows three reversible redox peaks corresponding to [dppf] 0/+ ( E 1/2 1 =0.470 V), [Pt(mtdt)] 0/+ ( E 1/2 2 =1.050 V) and [Pt(mtdt)] +/2+ ( E 1/2 3 =1.405 V) processes and a weak Pt–P coupling constant ( J Pt–P =2962 Hz) due to relatively strong electron-donor property of mtdt ligand. X-ray structural analyses were performed for the three complexes: (dppf)PtL where L=dmit, phdt and i -mnt. The P 2 PtS 2 core shows a distorted square planar geometry for the three complexes with P(1)–Pt–P(2) bite angle being larger than 96°. The S(1)–Pt–S(2) bite angle of the i -mnt complex is the smallest (74.42°) because of the formation of the four-membered ring.