Access to a novel niobium octahedral cluster core via soft chemistry: synthesis and structure of K 2.6Cs 3.4[Nb 6Cl 4O 4(OH) 4(CN) 6]·3H 2O containing isolated Nb 6Cl i4O i4(OH) i4(CN) a6 cluster unit

Abstract

The synthesis and the structure of K 2.6Cs 3.4[Nb 6Cl 4O 4(OH) 4(CN) 6]·3H 2O are described in the present work. It has been obtained by the interaction of Cs 2Ti 3Nb 12Cl 27O 8 oxychloride with an aqueous solution of potassium cyanide. The crystal structure—determined by single crystal X-ray diffraction at room temperature (monoclinic, C2/ c, a=13.4336(3) Å, b=15.9281(3) Å, c=15.9619(3) Å, β=90.2177(9)°, V=3415.3(1) Å 3, Z=4)—is built from a novel (Nb 6O i 4(OH) i 4Cl i 4) cluster core which exhibits for the first time four hydroxyl groups in addition to four chlorine and four oxygen atoms in inner position; six apical CN ligands complete the coordination of the Nb 6 cluster. Structural and electronic properties of this unit are discussed by comparison with other niobium oxychlorides and oxides based on (Nb 6Cl 12− x O x ) n+ cluster core.