MOLECULAR-STRUCTURES OF CYCLIC SULFILIMINES WITHOUT AND WITH INTRAMOLECULAR SULFUR-OXYGEN INTERACTION - AN X-RAY STUDY

3-Phenylbenzo[1.3.2]dithiazolium ylide 1.1 dioxide (1) and its o-metho xycarbonyl derivative (2) have been prepared and their structures esta blished by X-ray crystallography from diffractometer data. Compound 1 (C12H9NO2S2) crystallizes in the triclinic space group <P(1)over bar> with a=6.664(1), b=7.881(1), c=12.437(2) Angstrom, alpha=98.81(1), bet a=97.44(1), gamma=113.05(1)degrees, V=580.9(4) Angstrom(3), Z=2, D-c=1 .51 g.cm(-3) and mu(CuK alpha)=4.00 mm(-1). Compound 2 (C14H11NO4S2) c rystallizes in the orthorhombic space group P2(1)2(1)2(1), with a=7.62 0(1), b=8.887(1), c=20.022(2) Angstrom, V=1355.9(5) Angstrom(3), Z=4, D-c=1.57 g.cm(-3) and mu(CuK alpha)=3.65 mm(-1). The crystal structure s were solved by direct methods and refined to R=0.062 for 1 and R=0.0 28 for 2, using 1663 and 1424 observed reflections, respectively. In t he cyclic N-sulfonyl sulfilimines 1 and 2 the characteristic bond dist ances and bond angles involving S(IV) and S(VI) atoms do not differ si gnificantly from those found earlier for acyclic sulfilimines. Owing t o S(IV) O(carbonyl) close contact the sulfur(IV) atom in 2 exhibits a sulfuran-like configuration with almost linear (171 degrees) N=S(IV).. . O array (1.61+/-2.68=4.29 Angstrom). The conformations of 1 and 2 ha ve similar features. In both cases the five-membered dithiazolium ring is practically planar and the two aryl rings about sulfur(IV) atom ar e nearly perpendicular to the C-ar-S(IV)-C-ar plane (''butterfly confo rmation''). In contrast with acyclic sulfilimines, the benzene ring co nnected to S(VI) atom is constrained to be coplanar with the S(VI)-N-S (IV) plane (Koch and Moffitt's case I of conjugation).