Crystal and molecular structure of an eight-membered cyclic imidosulphite, 2-(2,4,6-trichlorophenylimino)perhydro-1,3,2,6-dioxathiazocine

Abstract

2-(2,4,6-Trichlorophenylimino)perhydro-1,3,2,6-dioxathiazocine crystallises in the triclinic space group P, with four molecules in a unit cell of dimensions a= 10.725(4), b= 11.730(2), c= 12.451(3)Å, α= 108.15(8), β= 92.92(7), γ= 93.50(7)°. The structure was refined to R 0.048 for 5 024 reflections. Two pseudo-enantiomorphic independent molecules are observed. In the solid state, the molecule assumes an approximate boat-chair conformation with transannular S ⋯ N distances of 2.94 and 2.99 Å. This weak interaction of electrostatic nature is also present in solution. In CDCl₃ and C₆D₆ i.r. and n.m.r. experiments are in agreement with the existence of an enantiomeric equilibrium of two isoenergetic boat-chair forms involving a pseudorotational path.