Ground state conformation of diphenylvinylphosphine sulfide and selenide

Single-crystal X-ray diffraction experiments have been performed on diphenylvinylphosphine sulfide ( 1 ): C₁₄H₁₃PS, space group P 2₁/c, a = 10.186(1) Ǎ, b = 11.918(1) Å, c = 11.426 Å, β = 112.22(2)°, V = 1284.1(2) ų, Z = 4, and diphenylvinylphosphine selenide ( 2 ): C₁₄H₁₃PSe, space group Pbca, a = 9.141 (3) Å, b = 16.458 (1) Å, c = 17.451 (1) Å, V = 2625.4 (9) ų, 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 > 3σ(I) in the case of 1 , and to R = 0.052 and R_w = 0.065 using 1953 unique reflections with I > 3σ(I) in the case of 2 . In close analogy to the previously 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 angles equal to 12.5° and 2.9° for 1 and 2 , respectively.