Synthesis, structure, and P-31 NMR of sulfur/oxygen-bridged incomplete cubane-type molybdenum and tungsten clusters with triphenylphosphine ligands

Sulfur/oxygen-bridged incomplete cubane type triphenylphosphine molybdenum- and tungsten-clusters [Mo3S4Cl4(H2O)(2)(PPh3)(3)]. 3THF (1A), [Mo3S4Cl4 (H 2O)(2)(PPh3)(3)]. 2THF (2A), [Mo3OS3Cl4(H2O)(2)(PPh3)(3)] . 2THF (1B), and [W3S4Cl4(H2O)(2)(PPh3)(3)] . 2THF (1C) were prepared from the corresponding aqua clusters and PPh3 in THF/MeOH. On recrystallization from THF, procedu res with and without addition of hexane to the solution gave 1A and 2A, res pectively, while the procedures gave no effect on the formation of 1B and 1 C. Crystallographic results obtained are as follows: 1A: monoclinic, P2(1)/ n, a = 17.141(4) Angstrom, b = 22.579(5) Angstrom, c = 19.069(4) Angstrom, beta = 96.18(2)degrees, V = 7337(3) Angstrom(3), Z = 4, R(R-w) = 0.078(0.10 2); 1C: monoclinic, P2(1)/c, a = 12.635(1) Angstrom, b = 20.216(4) Angstrom , c = 27.815(3) Angstrom, beta = 96.16(1)degrees, V = 7062(2) Angstrom 3, Z = 4, R(R-w) = 0.071(0.083). If the phenyl groups are ignored, the molecule [Mo3S4Cl4(H2O)(2) (PPh3)(3)] in 2A has idealized CS symmetry with the mirr or plane perpendicular to the plane determined by the metal atoms, while th e molecule in 1A does not have the symmetry. The tungsten compound 1C is is omorphous with the molybdenum compound 2A. P-31 NMR spectra of 1A, 2A, and 1C were obtained and compared with similar clusters with dmpe (1,2-bis(dime thylphosphino)ethane) ligands.