Crystal and Molecular Structure of Benzylidenimine Tetrasulfide, (C₆H₅CHN)₂S₄

Abstract

The structure of the title compound has been determined. Crystals are monoclinic with space group P 2 , l a , Z = 4, a = 13.83 ( A full-matrix least-squares refinement on 1085 unique reflections of positive intensity measure produced a conventional R of 0.066. The spiral arrangement of the S, chains (nearly generating a 3, axis) is such that the two aromatic rings are eclipsed. Alternation in bond length along the sulfur chain was observed, the long inner bond being 2.083(4) A and the shorter outer bonds averaging 2.026(3) ki in length. N o intermolecular non-bonding interactions involving sulfur were found.La structure du composC en titre a Cte determinee. Les cristaux sont monocliniques, degrouped'espace P2,la, avec Z = 4, a = 13.83 (1) Can. J. Chem., 51,3691 (1973) The reaction of tetrasulfur tetranitride with tion in the order long-short-long was found. benzylamine leads to a product (1) formulated (2) Possible similar alternation of bond lengths has as benzylidenimine tetrasulfide. This material been reported previously (12-14) in inorganic appears to be a rather common product from sulfur chains but with a lack of consistency or reactions of species containing sulfur and benzyl conviction. Only in the recent cases are differences groups; it has also been isolated from the reaction in sulfur-sulfur bond lengths clearly outside the of benzylamine with sulfur in the presence of lead experimental errors in the measurements. oxide (2,3), from the decomposition of N-benzylIn view of the interest in bond length alternaheptasulfurimide (4), from the reaction of sulfur tion in organotetrasulfides and to resolve any monochloride (5, 6), or disulfur trichloride (5) residual uncertainty in the structure of 1, we have with benzylamine and from the decomposition of determined the crystal and molecular structure of benzylamine disulfide (6). At least four alternate this material. structures have been suggested although the combined evidence of elemental analysis, molecular weight, i.r., and n.m.r. would seem to eliminate most of them.Recently, the structures of several tetrasulfides have been determined. These include tetraethoxy-2,3,4,5,10,11,12,13-octathiatricyclo-[12,2,2,2'679)]eicose-6,8,14,16,1 7,19-hexaene (2) (7), 1,2,3,4-tetrathiadecaline (3) (8), N,N1-dimethyl-3,6-epitetrathio-2,5-piperazinedione (4) (9, 10) and bis(cyclopentadieny1)tungsten tetrasulfide (5) (11). In 3, the 3 sulfur-sulfur bond lengths were of equal length while in 2 and 4 alternation of sulfur-sulfur bond lengths in the order short-long-short was observed and in 5 alterna- Experimental Crystal DataBenzylidenimine tetrasulfide, (C6H,CHN),S,, was obtained from the reaction of sulfur with benzylamine in the presence of lead oxide as previously described (6). Recrystallization from hot methanol gave yellow needles of m.p. 100.5-102 "C. Crystals suitable for X-ray analysis were subsequently grown from benzene solution.Weissenberg photographs (hkn, n = 0-5) showed systematic absences of type k = 2n + 1 on the OkO axis and h = 2n + 1 in the h01 lay...