PREPARATION, STRUCTURE, AND REACTIVITY OF HETEROMETALLIC SN-CONTAINING SINGLE-CUBE AND DOUBLE-CUBE DERIVATIVES OF [MO3SE4(H2O)(9)](4+) AND [W3SE4(H2O)(9)](4+)

The preparation and properties of Sn-containing derivatives of trinucl ear (M3Se44+)-Se-IV incomplete cuboidal clusters [Mo3Se4(H2O)(9)](4+) and [W3Se4(H2O)(9)](4+) are described. Addition of S( II )to [Mo3Se4(H 2O)(9)](4+) gives the single-cube [Mo3SnSe4(H2O)(12)](6+) in 2 M Hpts (pts(-) = p-toluenesulfonate) and [Mo-3(SnCl3)Se-4(H2O)(9)](3+) in 2 M HCl. The structure has been determined by X-ray crystallography on (N H2Me2)(6) [Mo-3(SnCl3)Se-4(NCS)(9)]. 0.5H(2)O. The reaction of Sn meta l with [Mo3Se4(H2O)(9)](4+) gives the first example of an Se-containin g corner-shared double cube, characterized by X-ray crystallography as [Mo6SnSe8(H2O)(18)](pts)(8). 2Hpts . 28H(2)O. The clusters [MoSnSe4 ( H2O)(12)](6+) and [Mo6SnSe8(H2O)(18)](8+) are also characterized by th e ease of elution in Dowex chromatography, ICP elemental analyses, and the stoichiometries of the oxidation with [Co(dipic)(2)](-). The prep aration of the single-cube [W3SnSe4(H2O)(12)](6+) in 2 M Hpts, [W-3(Sn Cl3)Se-4 (H2O)(9)](3+) in 2 M HCl, is also described. Conversion of [M o3SnSe4(H2O)(12)](6+) into corner-shared double-cubes [Mo6SnSe8 (H2O)( 18)](8+), [Mo6SnSe4S4(H2O)(18)](8+), [Mo6SnSe4(H2O)(18)](8+), [Mo3W3Sn Se8(H2O)(18)](8+), and [Mo3W3SnSe4S4(H2O)(18)](8+) was achieved by red uctive addition of [Mo3Se4(H2O)(9)](4+), [Mo3S4(H2O)(9)](4+) [W3Se4(H2 O)(9)](4+), and [W3S4(H2O)(9)](4+) using BH4-. A similar procedure was used for the conversion of [W3Se4(H2O)(9)](4+) into [W6SnSe8(H2O)(18) ](8+). Transfer of Sn( II )is observed in the reaction of [Mo3S4(H2O)( 9)](4+) with [Mo3SnSe4(H2O)(12)](6+), [W3SnSe4(H2O)(12)](6+), and [W3S nS4(H2O)(12)](6+) . With the inclusion of similar reactions of [Mo3Se4 (H2O)(9)](4+) etc., the order of affinities for S( II )uptake is Mo3S4 4+ > Mo3Se44+ > W3Se44+ > W3S44+. The displacement of In(I )from [W3In Se4(H2O)(12)](6+ )by Sn( II )is also consistent with equilibrium proce sses involving dissociation of the heteroatom.