A BIMETALLIC MAIN-GROUP OXIDE CLUSTER OF THE OXOVANADIUM BORATE SYSTEM - )[(VO)(12)O-4(B8O17(OH)(4))(2)(MN(H2O)(2))(2)].H2O

The hydrothermal reaction of (NH4)(2)B4O7, NaVO3, ethylenediamine, MnC l2. 4H(2)O and H2O in the molar ratio 2.74:4:4:1:175 at 170 degrees C for 5 days yields orange crystals of 12)O-4(B8O17(OH)(4)}(2){Mn(H2O)(2 )}(2)].H2O(1.H2O) in 75% yield. The structure consists of a continuous contorted V-12 ring, constructed from edge-sharing V(IV) square pyram ids. Two {B8O17(OH)(4))(14-) chains nestle in the cavities formed by t he V-12 ring. The octahedral Mn(II) sites bridge two neighboring [(VO) (12)O-4{B8O17(OH)(4)}(2)](12-) clusters to produce a mixed metal boron oxide network with two-dimensional covalent connectivity. Crystal dat a: monoclinic C2/c, a = 13.4324(2), b = 19.6998(1), c= 24.0521(3) Angs trom, beta = 98.820(1)degrees, Z = 4, D-calc = 2.282 g cm(-3); R = 0.0 462 for 7299 reflections. (C) 1998 Elsevier Science S.A. All rights re served.