SUBSTITUTED 1,2,4-THIADIAZOLIUMDICHLOROAU RATE(I) AND 1,2,4-THIADIAZOLIUMTETRACHLOROAURATE(III) AS PRODUCTS OF THE REACTION OF N-THIOCARBAMOYL-BENZAMIDINES WITH TETRACHLOROGOLD(III) COMPOUNDS

The reactions of N-diethylaminothiocarbonyl-benzamidines Et2N-C(S)-N=C (NHR)-Ph (1: R = Ph, 2: R = C3H7, 3: R = H) with gold(III) compounds w ere studied. Treatment of 1 and 2 with equivalent amounts of tetrachlo rogold acid gives 2,3-substituted diethylamino-1,2,4-thiadiazoliumdich loroaurates(I) (1a, 2a). With tetrachlorogold acid in excess 1 yields 2,3-diphenyl-5-diethylamino- 1,2,4-thiadiazolium-tetrachloroaurate(III ) 1b. With 3 and Na[AuCl4] bis(3-phenyl-5-diethylamino-1,2,4-thiadiazo lium) -chloride-tetrachloroaurate(III) 3b is produced. The structures of 1a, 2a and 3b were investigated by X-ray structure analysis. In 1a and 2a the dichloroaurate(I) ions are linear. In the 1,2,4-thiadiazoli um cations the N-C-bond lengths alternate characteristically. In 3b th e tetrachloroaurate(III) ion is square planar. The 1,2,4-thiadiazolium cation shows a different alternation of N-C bond lengths in compariso n with 1a and 2a which suggests changes in the thiadiazolium ring in 3 b to a tautomeric form as confirmed by the localization of the H atom at the N atom in ring position 4 instead of ring position 2. The struc tures of 1a, 1b, 2a and 3b were confirmed by elemental analysis, ES-MS , FAB-MS, H-1 and C-13 NMR and IR spectroscopy.