PREPARATION OF [NS][ALCL4] AND [NS][CF3SO3] AND REACTIONS OF THE THIAZYL CATION WITH THIADIAZOLES AND ORGANOSELENIUM HALIDES - X-RAY CRYSTAL-STRUCTURE OF [N2S2SECL][ALCL4]

The reaction of (NSCl)3with 3 mol of AlCl3at ca. 50 °C in the absence of a solvent provides a simple, high-yield synthesis of [NS][AlCl4]. The treatment of (NSCI)3with 3 mol of AgSO3CF3in 1,2C2H4CI2is a convenient in situ source of [NS][SO3CF3], However, a solution of [NS][AlCl4] in boiling 1,2-C2H4Cl2produces [(H2N)HCCH(NH2)][AlCl4]2after 24 h. The reactivity of thiazyl salts toward thiadiazoles, organoselenium halides, and chalcogens was monitored by 14N NMR spectroscopy, and stable products were isolated and characterized. The reactions of 2,1,3- and 1,2,3-benzothiadiazole with NS+X-give either Lewis acid adducts (X-= AlCl4 -, AsF6 -) and NSY (Y = Cl, F) or intensely colored charge-transfer complexes (X-= CF3SO3 -, AsF6 -) in which the NS+cation is attached to the heterocyclic ring on the basis of 13C NMR data. By contrast, 3,5-dimethyl-1,2,4-thiadiazole reacts with [NS][SO3CF3] to give a protonated adduct of the thiadiazole. The reaction of EtSeCl with [NS][AlCl4] yields [N2S2SeCl][AICl4] via a thermally unstable intermediate. The same final product and a small amount of [NS2][AICl4] are formed in the reaction of [NS][AlCl4] with selenium. By contrast, the reaction of PhSeCl with [NS][AlCl4] produces a dark green charge-transfer complex. The structure of the N2S2SeCl+cation was shown by X-ray crystallography to be a five-membered ring with chlorine attached to selenium. The crystals of [N2S2SeCl][AlCl4] are monoclinic, space group P21/n, with a = 9.237 (1) Å, b = 10.685 (2) Å, c = 11.332 (2) A, β = 92.65 (1)°, V = 1117.2 (2) Å3, and Z = 4. The least-squares refinement with anisotropic thermal parameters for all non-hydrogen atoms converged at R = 0.049 and Rw= 0.045 for 2817 unique observed reflections. The Se atom is 0.187 (5) Å out of the plane formed by the S2N2unit with d(Se-Cl) = 2.191 (1) Å and d(S-Se) = 2.293 (1) Å. The S-N bond lengths indicate a tendency toward localized π bonding in the NSN unit of the cation. Significant cation-anion interactions between one Cl atom of AlCl4 -and the Se and nearest S atom are observed. © 1990, American Chemical Society. All rights reserved.