SYNTHESIS AND CHARACTERIZATION OF DIASTEREOMERIC NICKEL(II) COMPLEXESOF BI(1-PHENYL-3,4-DIMETHYL-2,5-DIHYDRO-1H-PHOSPHOLE)

The reaction of -3,4-dimethyl-2,5-dihydro-1H-phosphole)]nickel(II) wit h silver tetrafluoroborate in dichloromethane/acetonitrile solution le ads to the formation of the meso (1) and racemic (2) diastereomers of -3,4-dimethyl-2,5-dihydro-1H-phosphole)]nickel(II) tetrafluoroborate a nd a single diastereomer of -3,4-dimethyl-2,5-dihydro-1H-phosphole)]ni ckel(II) tetrafluoroborate (3). These compounds were separated by frac tional crystallization and characterized by elemental analysis, physic al properties, H-1, H-1{P-31}, C-13{H-1}, and P-31{H-1} NMR spectrosco py, electronic spectroscopy, and cyclic voltammetry. The structures of complexes 1 and 2 were determined by X-ray crystallography. Complex 1 crystallizes in the monoclinic space group C2/c with a = 18.443(5) An gstrom, b = 14.139(2) Angstrom 18.535(3) Angstrom, beta = 104.19(2)deg rees, and Z = 4. Complex 2 crystallizes in the monoclinic space group P2 with a = 17.108(4) Angstrom, b = 9.512(3) Angstrom, c = 14.78(3) An gstrom, beta = 90.59(2)degrees, and Z = 2. Refinements converged to R( F) = 0.084 and 0.051 for 3572 and 2068 independent observed (I greater than or equal to 3 sigma(I)) reflections, respectively.