Synthesis and characterization of dinuclear niobium(IV) complexes with symmetrical and unsymmetrical ditertiary phosphines

Abstract

A series of dinuclear diamagnetic niobium(lV) complexes of the types Nb₂CI₈[φ₂- P- (CH₂)_n - P- φ₂]₂(where n= 1 to 6), Nb₂Cl₈[φ₂- P- CH = CH - P- φ₂]₂and Nb₂Cl₈[(p-FC₆H₄)₂P- (CH₂)₂ - P- φ₂]₂ have been synthesized by the reaction of niobium(IV) chloride tetrahydrofuran adduct in THF with symmetrical and unsymmetrical ditertiary phosphines viz., 1,2- bis(diphenylphosphino)methane (dppm), 1,2- bis( diphenylphosphino )ethane (dppe), 1,3-bis( diphenylphosphino )propane (dppp), 1,4-bis( diphenylphosphino )butane (dppb), 1,5-bis( diphenylphosphino )pentane (dpppent), 1,6-bis( diphenylphosphino )hexane (dpph), cis-l,2-bis(diphenylphosphino)ethylene (dppen) and 1-diphenylphosphino- 2-bis[ (p-fluoro )phosphino ]ethane (dp(pf)pe). All these complexes have been characterized by elemental analyses, IR, ¹H NMR, ³¹P NMR, ¹³C NMR spectroscopy and magnetic susceptibility measurements.