MECHANOCHEMICAL SYNTHESIS OF SOLUBLE COMPLEXES CONTAINING M3S74+ AND M3SE74+ FRAGMENTS FROM POLYMERIC M3Y7BR4 (M = MO, W, Y = S, SE) - THE CRYSTAL-STRUCTURE OF (PPN)2W3S7CL6

The interaction of solid W3S7Br4 or W3Se7Br4 with Et4NBr under vibrational mill conditions followed by extraction with acetonitrile resulted in the isolation of (Et4N)2W3S7Br6 (1) and (Et4N)2W3Se7Br6 (2) salts. Treatment of the product of the analogous reaction of Mo3Se7Br4 and Et4NBr with sodium diethyldithiocarbamate (Nadtc) resulted in [Mo3Se7(dtc)3]dtc (4). The M3Y7(4+) (Y = S, Se) cluster fragments are retained in all of these reactions. By dissolving 1 in conc. hydrochloric acid and adding PPNCl, the (PPN)2W3S7Cl6 salt (5) was obtained, for which an X-ray study has been performed. Selected distances for the cluster anion W3(mu-3-S)(mu-2-S2)3Cl6(2-) are 2.7270(7)-2.7445(6) angstrom for W-W, 2.360(3)-2.361(3) angstrom for W-(mu-3-S), 2.032(4)-2.052(4) angstrom for S-S, 2.429(3)-2.459(2) and 2.493(4)-2.519(3) angstrom for W-Cl (for cis and trans positions with respect to mu-3-S, respectively). Rather short distances (3.17-3.21 angstrom) between the chlorine atoms and sulphur atoms of the mu-2-S2 ligands of the adjacent anions were noted. The interaction of 2 with 1,2-bisdiphenylphosphine ethane(dppe) is accompanied by elimination of selenium to produce [W3Se4Br3(dppe)3]Br (6).