LYVSFQ WXVYPXYVSTO [NRNN 2014. 55 2 S201 – S218 542.06:546.77:546.88:548.736:549.46:54.057 OCTAHEDRAL CLUSTERS WITH MIXED INNER LIGAND ENVIRONMENT: SELF-ASSEMBLY, MODIFICATION AND ISOMERISM N.G. Naumov1,2, K.A. Brylev1,2, Y.V. Mironov1,2, S. Cordier3, V.E. Fedorov1,2 1Nikolaev Institute of Inorganic Chemistry, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia E-mail:
[email protected] 2Novosibirsk State University, Russia 3UMR Sciences Chimiques de Rennes, UR1-CNRS 6226, Université de Rennes 1, Campus de Beaulieu 35042 Rennes Cedex, France E-mail:
[email protected] Received March, 29, 2014 . Octahedral cluster complexes of transition metals are associated with halogen or chalcogen in- ner ligands to form edge-bridged {M6(2-X)12} or face-capped {M6(3-X)8} cluster cores. The partial exchange of X atoms leading to mixed inner ligand environment invokes a distortion of metallic cluster, reduction of symmetry as well as an isomerism of the cluster cores. This re- view summarizes preparation methods of mixed ligand cluster complexes with the general n n formulas [{M6(2-X)12}L6] or [{M6(3-X)8}L6] and their structural features. Keywords: octahedral cluster, ligand, structure, isomerism, substitution, niobium, molyb- denum, rhenium. INTRODUCTION In the chemistry of transition metal clusters the octahedral complexes are one of the most repre- sentative compounds [ 1—4 ]. There are two main structural types of the octahedral cluster complexes that are defined by composition and structure of the cluster core. Complexes of the first type are typi- cal for halides of niobium and tantalum and represent an octahedral metal cluster M6 with edges coor- m+ dinated by halide ions resulting in the core {M6(2-X)12} (M = Nb or Ta; X = F, Cl, Br, or I) (Fig.