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The clusters of niobium and tantalum [M_6X_(12)(ROH)_6]X_2 (R = alkyl) as precursors for the reactions in nonaqueous solvents

The hexanuclear halide clusters of niobium and tantalum of the composition [M_6X_(12)(ROH)_6]X_2 with loosely bonded aliphatic alcohol molecules, are suitable starting materials for the reactions of Nb_6 and Ta_6 clusters in nonaqueous solvents. The cluster [Ta_6Cl_(12)(CH_3OH)_6]Cl_2 has been already used as the precursor in synthetic procedure of methoxo clusters M_2[Ta_6Cl_(12)(OCH_3)_6]×nCH_3OH, M = alkali metal. Now, the clusters [M_6X_(12)(C_2H_5OH)_6]X_2, M = Nb, Ta; X = Cl, Br, have been used as precursors in the reactions with nitrogen bases. Microcrystalline substances of the composition [M_6X_(12)L_6]X_2, L = NH_3, CH_3CN, C_5H_5N, represent the first N-ligated species in chemistry of Nb_6 and Ta_6 clusters. Based on analytical and spectral data all octahedral coordination sites are occupied by nitrogen base molecules. Spectral, crystallographic and magnetic properties of these new clusters are discussed.

metal clusters; cluster precursors; alcoholate complexes

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