Molecular structures of cyclic sulfilimines without and with intramolecular sulfur-oxygen interaction: an X-ray study

Abstract 3-Phenylbenzo[1.3.2]dithiazolium ylide 1.1 dioxide ( 1 ) and its o -methoxycarbonyl derivative ( 2 ) have been prepared and their structures established by X-ray crystallography from diffractometer data. Compound 1 (C 12 H 9 NO 2 S 2 ) crystallizes in the triclinic space group P 1 with a = 6.664(1), b = 7.881(1), c = 12.437(2) A , α = 98.81(1), β = 97.44(1), γ = 113.05(1)°, V = 580.9(4) A 3 , Z = 2, D c = 1.51 g.cm −3 and μ (CuK α ) = 4.00 mm −1 . Compound 2 (C 14 H 11 NO 4 S 2 ) crystallizes in the orthorhombic space group P 2 1 2 1 2 1 , with a = 7.620(1), b = 8.887(1), c = 20.022(2) A , V = 1355.9(5) A 3 , Z = 4, D c = 1.57 g.cm −3 and μ (CuK α ) = 3.65 mm −1 . The crystal structures were solved by direct methods and refined to R = 0.062 for 1 and R = 0.028 for 2 , using 1663 and 1424 observed reflections, respectively. In the cyclic N -sulfonyl sulfilimines 1 and 2 the characteristic bond distances and bond angles involving S(IV) and S(VI) atoms do not differ significantly from those found earlier for acyclic sulfilimines. Owing to S(IV)…O(carbonyl) close contact the sulfur(IV) atom in 2 exhibits a sulfuran-like configuration with t almost linear (171°) N = S(IV)…O array ( 1.61 + 2.68 = 4.29 A ). The conformations of 1 and 2 have similar features. In both cases the five-membered dithiazolium ring is practically planar and the two aryl rings about sulfur(IV) atom are nearly perpendicular to the C ar S(IV)C ar plane (“butterfly conformation”). In contrast with acyclic sulfilimines, the benzene ring connected to S9VI) atom is constrained to be coplanar with the S(VI)NS(IV) plane (Koch and Moffitt's case I of conjugation).