GROUND-STATE CONFORMATION OF DIPHENYLVINYLPHOSPHINE SULFIDE AND SELENIDE

Single-crystal X-ray diffraction experiments have been performed on di phenylvinylphosphine sulfide (1): C14H13PS, space group P2(1)/c, a = 1 0.186(1) angstrom, b = 11.918(1) angstrom, c = 11.426 angstrom, beta = 112.22(2)-degrees, V = 1284.1(2) angstrom 3, Z = 4, and diphenylvinyl phosphine selenide (2): C14H13PSe, space group Pbca, a = 9.141(3) angs trom, b = 16.458(1) angstrom, c = 17.451(1) angstrom, V = 2625.4(9) an gstrom 3, Z = 8. The structures were solved by direct methods and were refined by full matrix least-squares calculations to R = 0.046 and R( w) = 0.058 using 2554 unique reflections with I > 3-sigma(I) in the ca se of 1, and to R = 0.052 and R(w) = 0.065 using 1953 unique reflectio ns with I > 3-sigma(I) in the case of 2. In close analogy to the previ ously studied vinyl phosphine oxides both 1 and 2 were found to exist in the s-cis conformation with the pertinent C = C-P = X dihedral angl es equal to 12.5-degrees and 2.9-degrees for 1 and 2, respectively.