Crystal and molecular structure of 1,2,3,4-tetrahydro-1,2,2,3,4,4-hexamethylphosphinoline 1-oxide

Abstract

The crystal structure of 1,2,3,4-tetrahydro-1,2,2,3,4,4-hexamethylphosphinoline 1-oxide has been determined by X-ray diffraction techniques with diffractometer data. The crystals grow in a monoclinic space group C2/c with lattice parameters a= 29·144 ± 0·009, b= 6·122 ± 0·005, c= 16·269 ± 0·007 Å, β= 91·76 ± 0·10°, Z= 8. The phosphorus atomic positions were located from a three-dimensional Patterson map and the structure was solved by three subsequent Fourier syntheses and was refined to a final R of 6·7% by an anisotropic least-squares method. The conformation of the molecule is similar but not identical to tetralin, in that both the alicylic ring in tetralin and the phosphorus heterocycle resemble cyclohexene. The P–C distances vary from 1·762 to 1·864 Å. The angles around phosphorus and the saturated carbon atoms are close to tetrahedral as expected.