Stereochemical structure of alkylidenephosphines. X-ray crystallographic investigation of C,C-bis(dimethylamino)methylenephosphine

An x-ray crystallographic investigation of C,C-bis(dimethylamino)methylenephosphine was undertaken. At room temperature the compound is a liquid melting at about -12/sup 0/C. The investigation was carried out on a diffractometer with lambdaMoK/sub ..cap alpha../ radiation at -110/sup 0/C, 1289 reflections were measured, and R = 0.029. The crystals are monoclinic with a = 5.303, b = 12.659, c = 11.532 A, ..beta.. = 93.06/sup 0/, V = 773.0 A/sup 3/, Z = 4, d/sub calc/ = 1.14 g/cm/sup 3/, space group Cc. The principal geometric parameters of the molecule are as follows: P,C 1.740, P-H 1.42, C(sp/sup 2/)-N 1.348 and 1.391 A, CPH 103, PCN 124.2 and 121.6, NPC 114.2/sup 0/, NCPH 19 and 161/sup 0/. The main relationships governing the stereochemical structure of alkylidenephosphines were established on the basis of a detailed analysis of the obtained data and of published data.