THE EVALUATION OF SINGLET-TRIPLET SEPARATIONS FOR [W-2(MU-H)(MU-CL)CL-4(MU-DPPM)(2)] AND [W-2(MU-H)(2)(MU-O2CC6H5)(2)CL-2(P(C6H5)(3))(2)] BASED ON P-31 NMR AND CRYSTALLOGRAPHIC DATA

The singlet-triplet separations for the edge-sharing bioctahedral (ESB O) complex W-2(mu-H)(mu-Cl)(Cl-4(mu-dppm)(2) .(THF)(3) (II) has been s tudied by P-31 NMR spectroscopy. The structural characterization of [W -2(mu-H)(2)(mu-O2CC6H5)(2)Cl-2(P(C6H5)(3))(2)] (I) by single-crystal X -ray crystallography has allowed the comparison of the energy of the H OMO-LUMO separation determined using the Fenske-Hall method for a seri es of ESBO complexes with two hydride bridging atoms, two chloride bri dging atoms and the mixed case with a chloride and hydride bridging at om. The complex representing the mixed case, [W-2(mu-H)(mu-Cl)Cl-4(mu- dppm)(2) . (THF)(3)] (II), has been synthesized and the value of -2J d etermined from variable-temperature P-31 NMR spectroscopy.