Abstract

The reaction of NbCl5 with aromatic organic acids and ethanol has been found to yield the first examples of trifunctional chloro alkoxy carboxylate niobium(V) complexes Nb2Cl4(OEt)4(O2CR)2 (R = Ph (1), p-FC6H4, p-ClC6H4, p-IC6H4, p-MeC6H4). Attempts to obtain related compounds by the use of different molar ratios of reactants under a variety of conditions have proved unsuccessful. The structure of 1 has been determined by single crystal X-ray crystallography, the data being as follows: triclinic space group P1 with unit cell dimensions a = 10.689(3), b = 9.548(2), c = 9.552(2) à , V = 753.90 à 3, Z = 2. The structure was refined to R = 0.0623 (R� = 0.0677) with 1347 reflections having I� 3�(I). The dinuclear unit contains unique unsymmetrical bridging carboxylate groups, as well as terminal chlorine atoms and ethoxy groups. The crystal contains chains of dimers which exhibit face-to-face �-� interactions between the aromatic rings of the benzoate ligands. © 1994.