Reaction of MO42-(M = Mo, W) with [(CH3)2(CH3(CH2)7)Si]2Se provides a new synthetic route to the tetraselenometalates MSe42-. Reaction of MSe42-with Se8SeS2or Se4(NC5H10)2affords the MQ(Se4)22-ion with Q = Se, S, or O, respectively. 77Se NMR studies of this system confirm the general assignment trends of terminal Se (> 1200 ppm), “metal bound” Se (1200-600 ppm), and ring Se (< 600 ppm). The M= Mo series resonates at lower field than does the M = W series. These trends are in agreement with those seen in 170 and previous 77Se NMR studies. The compound [NEt4]2[MoO(Se4)2] crystallizes in the monoclinic space group P21/c with a = 9.287 (2) Å, b = 17.132 (4) Å, c = 18.353 (4) Å, β = 97.38 (1)°, and Z = 4. The MoO(Se4)22~ ion shows square-pyramidal coordination of the MoIVcenter by the apical O atom and the two bidentate Se42-units. [PPh4]2[WS(Se4)2] crystallizes in the monoclinic space group P21/a with a = 18.366 (7) Å, b = 12.873 (6) Å, c = 20.666 (8) Å, β = 100.74 (1)°, and Z = 4. WS(Se4)22-is structurally analogous to MoO(Se4)22-All of the MSe4(M = Mo, W) rings exhibit conformations similar to that of cyclopentane.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Inorganic Chemistry