DICARBONYLTUNGSTEN(II) THIOLATE COMPLEXES OF HYDRIDOTRIS(3,5-DIMETHYLPYRAZOLYL)BORATE

A series of hydridotris(3,5-dimethylpyrazolyl)borate tungsten(II) thiolate complexes of the general type Tp'W-(CO)2(SR) (R = Me, Et, (i)Pr, CH2Ph, and P-C6H4NO2) has been synthesized by reaction of the appropriate sodium thiolate or mercaptan with Tp'W(CO)2I (1). The structures of these organothiolate complexes were elucidated on the basis of their IR and H-1 and C-13 NMR spectra and elemental analysis data. In addition, single-crystal X-ray diffraction was used to structurally characterize two of the complexes, Tp'W(CO)2(S-p-C6H4NO2) (4) and Tp'W(CO)2(SCH2Ph) (7). Both complexes crystallized in the triclinic space group P1BAR with Z = 2. Unit cell dimensions for 4 were a = 10.517(2) angstrom, b = 12.016(5) angstrom, and c = 13.904(3) angstrom with angles alpha = 77.25(3)-degrees, beta = 76.44(2)-degrees, and gamma = 64.23(2)-degrees. Refinement of 357 variables over 3706 reflections led to an R value of 0.044 and R(W) of 0.065. Unit cell dimensions for 7 were a = 9.709(2) angstrom, b = 10.230(2) angstrom, and c = 15.355(3) angstrom with angles alpha = 72.92(2)-degrees, beta = 84.32(2)-degrees, and gamma = 64.87(1)-degrees. Refinement of 316 variables over 4185 reflections led to an R value of 0.047 and R(w) of 0.057. The thiolate substituent is located approximately in the molecular mirror plane in both of these complexes. In each case the OC-W-CO angle is acute for electronic reasons originating in the d4 metal configuration.