Mononuclear, oligonuclear and polynuclear metal coordination compounds with 1,2,4-triazole derivatives as ligands

1,2,4-Triazole and its derivatives have gained great attention as ligands t o transition metals by the fact that they unite the coordination geometry o f both pyrazoles and imidazoles, and in addition exhibit a strong and typic al property of acting as bridging ligands between two metal centres. In thi s bridging capacity, the 1,2,4-triazole ligands show a great coordination d iversity, especially when the triazole nucleus is substituted with addition al donor groups. This property together with their strong sigma donor prope rties and the relative ease of synthesis make them very appealing for the d esign of new polynuclear metal complexes with interesting properties. A num ber of X-ray structures have been evaluated in some detail in the present p aper. (C) 2000 Elsevier Science S.A. All rights reserved.