| Abstract: | Azido Derivatives of the Pentamethylcyclopentadienyl Vanadium(IV)-Fragment. Molecular Structures of the Binuclear Complexes Cp*VCl(N3)(μ-N3)]2 and Cp*V(N3)2(μ-N3)]2 The stepwise reaction of Cp*VCl3 with excess trimethylsilyl azide (Me3Si–N3) in solution leads to the paramagnetic, azido-bridged complexes Cp*VCl2(μ-N3)]2 ( 3 ), Cp*VCl(N3)(μ-N3)]2 ( 4 ) and Cp*V(N3)2(μ-N3)]2 ( 5 ) which were characterized by their IR and mass spectra. The azide-rich binuclear complex 5 is also formed if a pentane solution of Cp*V(CO)4 is stirred in the presence of excess Me3Si–N3 in an open vessel. According to the X-ray structure analyses both 4 and 5 are centrosymmetric molecules with a planar V(N)2V four-membered ring. In the absence of free trimethylsilyl azide, solutions of 3 – 5 lose dinitrogen slowly; in the presence of traces of air, 5 is thereby converted to the diamagnetic, oxo-bridged complex Cp*V(O)(N3)]2(μ-O) ( 6 ). |
