Benzodithiazolium chlorooxomolybdate(V): Preparation and crystal structure of (C6H4NS2)[MoOCl4] and (C6H4NS2)[MoOCl4 center dot H2O]

Red benzo-1,3,2-dithiazolium-chlorooxomolybdate(V) (C6H4NS2)[MoOCl4] (1) was obtained by the reaction of benzo-1,3,2-dithiazoliumchloride and molybdenum(V)chloride oxide in dichlormethane under solvothermal conditions at 70 degrees C. In the presence of small amounts of concentrated hydrochloric acid the yellow compound (C6H4NS2)[MoOCl4 center dot H2O] (2) is formed under analogue conditions. Both crystal structures (1: monoclinic, C2/c, a = 799.2(1), b = 2091.5(2), c = 791.5(1) pm, beta = 102.2(1)degrees, Z = 4; 2: monoclinic, Cc, a = 953.7(1), b = 2468.9(3), c = 608. 1 (1) pm, beta = 112.5(1)degrees, Z = 4) contain the planar benzo-1,3,2-dithiazolium ion. Within the structure of I the molybdenum atoms in the [MoOCl4](-) ions are coordinated in a square pyramidal fashion with an oxygen atom in apical position and the basal plane formed by chlorine atoms. The nitrogen atom of the cation, which bears a partial negativ charge, expands the coordination to a distorted octahedron. The structure therefore is made up of ionic pairs {(C6H4NS2)(+) [MoOCl4](-)} with a Mo-N distance of 266 pm. 1 is paramagnetic with a magnetic moment of 1.7 B.M. corresponding to one unpaired electron per formula unit. In the structure of 2 the coordination of the [MoOCl4](-) ion is expanded by the oxygen atom of a coordinating water molecule. The structure is dominated by hydrogen bonds between the oxygen atoms of the [MoOCl4 center dot H2O](-) ions which cause the concatenation of the anions to infinite chains.