SYNTHESES AND ELECTROCHEMISTRY OF INCOMPLETE CUBANE-TYPE CLUSTERS WITH M3S4 CORES (M = MO, W) - X-RAY STRUCTURES OF [W3S4(H2O)9](CH3C6H4SO3)4.9H2O, NA2[W3S4(HNTA)3].5H2O, AND (BPYH)5[W3S4(NCS)9].3H2O

Facile synthetic methods for [Mo3(mu(3)-S)(mu-S)3(H2O)9]4+ (4') and [W3(mu(3)-S)(mu-S)3(H2O)9]4+ (1') are described, (NH4)2MoS4 (or Na2[Mo2O2S2(cys)2].4H2O) and (NH4)2WS4 being used for starting materials, respectively. Synthetic methods for derivative clusters with M3S4 cores (M = Mo, W), [W3S4(Hnta)3]2-, [W3S4(NCS)9]5-, and [Mo3S4(Hnta)3]2-, are also described. Crystal structures of [W3S4(H2O)9](CH3C6H4SO3)4.9H2O (1), Na2[W3S4(Hnta)3].5H2O (2a), and (bpyH)5[W3S4(NCS)9].3H2O (3) were determined. Compound 1 crystallized in the triclinic space group P1BAR with a = 15.353 (7) angstrom, b = 16.733 (6) angstrom, c = 12.003 (5) angstrom, alpha = 95.49 (3)-degrees, beta = 108.42 (3)-degrees, gamma = 101.96 (4)-degrees, V = 2818.7 (22) angstrom 3, and Z = 2. Compound 2a crystallized in the monoclinic space group P2(1)/a with a = 21.712 (6) angstrom, b = 12.711 (6) angstrom, c = 13.378 (4) angstrom, beta = 102.09 (3)-degrees, V = 3610.4 (23) angstrom 3, and Z = 4. Compound 3 crystallized in the triclinic space group P1BAR with a = 12.607 (5) angstrom, b = 24.893 (9) angstrom, c = 12.108 (4) angstrom, alpha = 92.98 (3)-degrees, beta = 90.96 (3)-degrees, gamma = 77.34 (3)-degrees, V = 3702.4 (24) angstrom 3, and Z = 2. The cluster cation and anions have an approximate symmetry of C3-upsilon. Current-sampled dc polarograms and cyclic voltammograms of [M3S4(Hnta)3]2- (M = Mo (5'), W (2')) show three consecutive one-electron reductive steps in alkaline solution (pH 11-12): E1/2 (V vs Ag/AgCl) = -0.64, -1.08, -1.39; -1.12, -1.41, -1.88, respectively. These steps correspond to the change of oxidation states of the three metals in each cluster: (IV,IV,IV) --> (IV,IV,III) --> (IV,III,III) --> (III,III,III). Electronic spectra of one-electron reduction products, the oxidation state being (IV,IV,III), obtained by bulk electrolyses of 5' and 2' have been reported for the first time, and the absorption maxima are 400, 620, and 720 sh nm for [Mo3S4(Hnta)3]3- and 557, 597, and 708 nm for [W3S4(Hnta)3]3-.