Titanocene(IV) and vanadocene(IV) complexes of dicyanomethanidobenzoate

The new titanocene and vanadocene complexes of the non-linear pseudohalides Cp2Ti(dcmb)2, Cp2VCl(dcmb), (η5-C5H4Me)2VCl(dcmb) and Cp2V(dcmb)2 were prepared by reaction of titanocene dichloride (Cp2TiCl2) and vanadocene dichlorides (Cp2VCl2, (η5-C5H4Me)2VCl2) with dicyanomethanidobenzoic acid (dcmbH, PhC(OH)C(CN)2). These reactions have proven that the dcmb ligand could be coordinated to the central metal by oxygen or nitrogen donor atoms. The bonding mode of the dcmb ligand reflects properties of the central metal. The strongly oxophilic titanium(IV) shows the bonding through oxygen atom while bonding through nitrogen atom was observed for less oxophilic vanadium(IV). The bonding fashion of the dcmb ligands was determined by spectroscopic methods. X-ray diffraction analysis was used for the structure determination of the compounds dcmbH·H2O, Cp2Ti(dcmb)2·CH2Cl2, (η5-C5H4Me)2VCl(dcmb) and [Cp2V(OC(Ph)C(CN)C(OMe)NH)][dcmb].

The synthesis of Cp2Ti(dcmb)2, Cp2VCl(dcmb), (η5-C5H4Me)2VCl(dcmb) and Cp2V(dcmb)2 is described. This study proves that dicyanobenzoate (dcmb, PhC(O)C(CN)2]−) could be coordinated via oxygen or nitrogen donor atoms. The bonding mode reflects properties of the central metal. The strongly oxophilic titanium(IV) shows bonding through oxygen atom while vanadium(IV) through nitrogen atom.Figure optionsDownload as PowerPoint slide