SYNTHESIS, CRYSTAL-STRUCTURE, AND IR INVESTIGATIONS OF [(NH3)(5)V-O-V(NH3)(5)]I-4-CENTER-DOT-NH3 AND [(NH3)(5)TI-O-TI(NH3)(5)]I-4-CENTER-DOT-NH3

The reaction of VI2 or TiI3, respectively, with ammonia in the presenc e of traces of water or oxygen, respectively, leads to [(NH3)(5)M-O-M( NH3)(5)]I-4 . NH3 with M = V, Ti. Their structures were solved by X-ra y single crystal data: Pbca (No. 61), Z = 4, M = V: a = 12.482(4) Angs trom, b = 14.819(6) Angstrom, c = 13.286(5) Angstrom, N(F-o(2) greater than or equal to 3 sigma F-o(2)) = 983, N(variables)= 88, R/R(w) = 0. 053/0.063, M = Ti: a = 12.628(4) Angstrom, b = 14.970(4) Angstrom, c = 13.359(3) Angstrom, N(F-o(2) greater than or equal to 3 sigma F-o(2)) = 1188, N(variables)= 88, R/R(w) = 0.043/0.047. The structures consis t of corner sharing octahedra double units [(NH3)(5)M-O-M(NH3)(5)](4+) with eclipsed conformation which are stacked together according to th e motif of a distorted cubic face centered arrangement for the bridgin g oxygen atoms. IR spectroscopic investigations of the undeuterated va nadium compound and of 5% deuterated samples hint to N-H ... I hydroge n bridge bonds and to remarkable n-bonding between the transition meta l and the bridging oxygen atoms.