Two polymorphs of tetraethylammonium [hydrogen tris(3,5-dimethylpyrazolyl)borato]di-μ2-sulfido-disulfido(η2-tetrasulfido)ditungsten(V) with Z'=1 and 2

Two polymorphs of the title compound, (C8H20N)[W2S4(S-4)(C15H22BN6)], have been obtained unexpectedly by attempted recrystallization of a mixed-metal-sulfur cluster complex from different solvents. The dinuclear complex anion contains WV in two different coordination environments, one of them distorted octahedral with a tris(pyrazolyl)borate anion, a terminal sulfide and two bridging sulfide ligands, the other distorted square-pyramidal with a terminal sulfide, two bridging sulfide and a chelating tetrasulfide ligand. The three independent anions in the two polymorphs have essentially the same geometry. The central W2S2 ring is a slightly folded rhombus with acute angles at the S atoms, and the WS4 chelate ring is an envelope with one noncoordinating S atom as the flap. The second polymorph, with Z' = 2 and pseudo-inversion symmetry relating the anions of the asymmetric unit, also displays pseudo-translation features in its layer structure, and all examined crystals were found to be twinned, possibly as a consequence of this structural feature.