Crystal and molecular structure of 1,1-dimethyl-2,4,6-triphenylphosphorin, a phosphorus analogue of pyridine

Abstract

The structure of 1,1-dimethyl-2,4,6-triphenylphosphorin, C₂₅H₂₃P, has been determined by single-crystal X-ray diffraction methods. The orange-red crystals are triclinic, space group P, with a= 12·840(10), b= 9·463(8), c= 10·039(9)Å, α= 67·41(15), β= 106·45(15), γ= 68·57(15)°, Z= 2. The final R factor for 1868 reflections, the intensities of which were measured on a linear diffractometer, is 0·066. The phosphorin ring, which is the phosphorus analogue of the pyridine ring, is almost planar, the largest deviation from its least-squares plane being 0·055 Å for one of the carbon atoms. Only two different bond lengths were observed in this ring, phosphoruscarbon (average 1·749 Å) and carbon–carbon (average 1·393 Å).