Polynuclear transition metal complexes of meta•••metal-bridging compartmental pyrazolate ligands

The present article reviews the structures and properties of di-, oligo- and polynuclear transition metal complexes of substituted pyrazolate (pz) ligands with ligating side arms (D-n) in which the N-2-unit of the pyrazole ring acts as a bridge between two metal centres. Extensive literature surveys covering the literature until the beginning of 2008 of symmetrical 3,5-disubstituted ligands of the type D-pz-D-, D-2-pz-D-2- and D-3-pz-D-3 with uni-, bi-and terdentate side arms, respectively, as well as of unsymmetrical 3,5-disubstituted ligands of the type D-n(1)-pz-D-m(2). are presented together with a comprehensive survey of the structurally characterised complexes thereof. Catalytic and/or stoichionnetric reactions of the dinuclear systems are discussed where appropriate. (C) 2009 Elsevier B.V. All rights reserved.