A New Double Bond Metathesis Reaction: Conversion of an Nb=Nb and an N=N Bond into Two Nb=N Bonds

Article abstract of DOI:10.1021/ja00329a018

Nb2Cl6(Me2S)3 reacts with azobenzene, C6H5N=NC6H5, to afford a red crystalline product, (NbCl2(Me2S)(NC6H5))2(μ-Cl)2 in 50-60percent yields.The compound has been characterized by NMR, IR, mass spectrometry and X-ray cristallography.It is a centrosymmetric molecule in which each of two niobium(V) atoms have distored octahedral coordination, with the ligand set consisting of two bridging Cl atoms, with one normal (2.462(2) Angstroem) and one long (2.762(2) Angstroem) bond, two mutually cis terminal chlorine atoms with Nb-Cl distances of 2.325(3) Angstroem and 2.344 (3) Angstroem, one Nb-SMe2 bond, 2.654(3) Angstroem, and one Nb=NC6H5 bond, 1.773(7) Angstroem.The long Nb-Cl bridge bond is trans to the Nb=NC6H5 bond.The dinuclear molecule can be regarded as the product of an inorganic double bond metathesis reaction in which Nb=Nb and N=N bonds react to yield two Nb=N bonds.The Nb=N-C group is practically linear, 175.1(7) deg.The compound crystallizes in space group C2/c with unit cell dimensions of a=20.736(4) Angstroem, b=7.671(1) Angstroem, c=16.780(3) Angstroem, β=96.86(2) deg, V=2650(2) Angstroem³, and Z=4.Refinement, using a data to parameter ratio of 9.4, converged with an unweighted discrepancy index of 4.89percent.