P-31 NMR-STUDIES ON SULFUR OXYGEN-BRIDGED INCOMPLETE CUBANE-TYPE MOLYBDENUM CLUSTER COMPOUNDS - X-RAY STRUCTURES OF [MO3OS3(DTP)(4)(CH3CN)]AND [MO3OS3(OAC)(DTP)(2)(PY)(2)(OC2H5)]/

A series of sulfur/oxygen-bridged incomplete cubane-type molybdenum cl uster compounds [Mo3OnS4-n(DTP)(4)(L)] (n = 0-3; DTP = diethyl dithiop hosphate, L = monodentate ligand), and their ligand substitution deriv atives were prepared by the reaction of the corresponding aqua ions wi th the ligand DTP. The crystallographic results obtained are as follow s. [Mo3OS3(DTP)(4)(CH3CN)] : triclinic, P ($) over bar 1, a = 14.134(1 3) Angstrom, b = 16.413(16) Angstrom, c = 0.654(9) Angstrom, alpha = 9 8.08(10)degrees, beta = 112.23(6)degrees, gamma = 77.03(9)degrees, V = 2225.3(37) Angstrom(3), Z = 2, no. of unique data (\F-0\ greater than or equal to 6 sigma\F-0\) = 4810, R = 4.79%. [Mo3OS3(OAc)(DTP)(2)(Py) (2)(OC2H5)] : triclinic, P ($) over bar 1, a = 13.985(7) Angstrom, b = 14.359(7) Angstrom, c = 12.012(4) Angstrom, alpha = 96.01(3)degrees, beta = 104.37(3)degrees, gamma = 114.20(3)degrees, V = 2072.3(17) Angs trom(3), Z = 2, no. of unique data (\F-0\ greater than or equal to 3 s igma\F-0\) = 4944, R = 4.62%. Of four DTP ligands in [Mo3OS3(DTP)(4)(C H3CN)], three are terminal and one is bridging. Both DTP ligands in [M o3OS3(OAc)(DTP)(2)(Py)(2)(OC2H5)] are terminal, and an acetato ligand is bridging. P-31 NMR spectra of these cluster compounds were measured in a solution of o-dichlorobenzene and acetonitrile. The P-31 NMR spe ctra of these cluster compounds presented much information about the s tructure, interaction between the ligands and the cluster core, solven t effect, lability of the ligands, and isomerization of this duster co mpound series. The assignment of the chemical shifts to each distinct ligand under different circumstances was successfully accomplished. Th e site of the loosely-coordinated solvent ligand L was kinetically act ive and informative to the assignments of the spectra. The symmetry an d chemical properties of the central trinuclear cluster core Mo3OnS4-n (n = 0-3) were also well reflected in their spectral appearance.