Synthesis of Nickel Precursors Derived from 1,1'-Bis(Diphenylchalcogenophosphoryl)Ferrocene Analogue and Their Catalytic Oxidation Reaction Studies

Two equivalents of sulphur and selenium on reaction with 1,1'-bis(diphenylphosphino)ferrocene (dppf) resulted compound of composition [Fe{C5H4P(E)Ph2}2] (E = S, Se). The latter resulted phosphine derivative on reaction with NiCl2·6H2O afforded an additive product [NiCl2(dppfE2)] (dppf = Fe{C5H4PPh2}2; E = S, Se) which on further treatment with another equivalent of [NiCl2(dppfE2)] followed by the addition of sodium tetraphenylborate yielded a binuclear complex [Ni2(µ-Cl)2(dppfE2)](BPh4)2 (E = S, Se). All these complexes were characterized by elemental analysis, IR, 1H and 31P{1H} NMR spectroscopy. The molecular structure of [Fe{C5H4P(Se)Ph2}2] was determined by single crystal X-ray diffraction. The nanoparticles of complex [NiCl2{Fe(C5H4P(S)Ph2)2}] (1a) and [NiCl2{Fe(C5H4P(Se)Ph2)2}] (1b) was prepared through hydrothermal method. The resulting composites have further been applied for the catalytic oxidation of benzyl alcohol to aldehyde.