Molecular polarisability. Conformations as solutes of the molecules Ph2X, where X = O, S, Se, and NH

Abstract

The dipole moment and molar Kerr constant of Ph₂Se are 1·37D and 15·7 × 10^–12, respectively. The four molecules of the title may adopt conformations in which the phenyl groups are rotated about their C–X bonds by angles ϕ₁ and ϕ₂ out of coplanarity with the C–X–C triangle. On present evidence decisions between models of type C (ϕ₁= O, ϕ₂= 90°) and others of type D (ϕ₁=ϕ₂= 37° for Ph₂O, 46° for Ph₂S, 48° for Ph₂Se, and 75° for Ph₂NH) cannot be made with certainty.