SYNTHESIS, STRUCTURES, AND PROPERTIES OF CYCLOTHIASELENAZENIUM CATIONS [SE2N2S]2(2+), [XSE2N2S]+,[SE2N2S]2+,[SES3N5]+ AS WELL AS CL2SE2N2S AND SESN2.TICL4

Bis(sulfinylamino)selane (1), prepared from Se2Cl2 and (CH3)3SiNSO, reacts with Lewis acids such as MF5 (M = As, Sb, Nb) and BF3 to form bis(1,3,4,2,5-thiadiselenadiazolium) cations (3) with counter anions AsF6- (3a), SbF6- (3b), NbF6- (3c), BF4- (3d). Treatment of Se2Cl2 with LiN[Si(CH3)3]2 leads to [(CH3)3Si]2NSexN[Si(CH3)3]2 (x = 1, 2a; 2, 2b). From 2a and SeCl4 explosive Se4N4 is obtained. Chlorination of 3a and 3c gives [ClSe2N2S] + [MF6]- (M = As, 4a, and Nb, 4c). Analogous bromination of 3a provides [BrSe2N2S] + [AsF6]- (4b). This type of chlorinated five-membered rings is also obtained directly from 1 and SbCl5 and PCl5 or SeCl4. The products isolated are [ClSe2N2S] + [SbCl6]- (4d) and [ClSe2N2S] + Cl- (4e). - A covalent species 5, isomeric to 4e, is obtained from 1 and POCl3, and a four-membered ring SeSN2. TiCl4 (6) from 1 and TiCl4. When 3a or 1 is treated with a two- or threefold excess of AsF5 the stable dication [Se2N2S]2+ (7) is formed. It arises also from 4e and AgAsF6. Attempts to replace TiCl4 in 6 by AsF5 lead to [SeS3N5] + [AsF6]- (8) with a bicyclic structure for the cation. X-ray structure analyses for 1, 4c, 4d, 4e, 5, and 8 are performed.