CONDUCTOMETRIC AND SPECTROSCOPIC INVESTIGATIONS ON THE REACTIONS BETWEEN N-METHYLTHIAZOLIDINE-2(3H)-SELONE (1) AND N-METHYLBENZOTHIAZOLE-2(3H)-SELONE (2) WITH BR-2

The formation of the compounds C4H7Br2NSSe (3), (C4H7BrNS)(2)[SeBr6] ( 4) and C8H7Br2NSSe (5) from the reaction of the title selenium donors (1 and 2) with molecular dibromine in CH2Cl2 and MeCN solutions has be en investigated by Se-77 and C-13 NMR: UV-visible spectroscopies and b y conductometric measurements. In the conductometric titrations of I o r 2 with dibromine: the very low values of conductivity recorded up to the 1 : 1 Br-2/1(2) molar ratio indicate the formation of the non-con ducting hypervalent selenium compounds 3 and 5, as confirmed by UV-vis ible and NMR spectroscopies. Above this ratio, 1 and 2 behave differen tly; in fact, for both of them the conductivity values increase on inc reasing the amount of added dibromine, but the values recorded for 1, that are much higher than those for 2, are time-dependent. This indica tes a kinetic transformation of 1 that has been shown to lead to the p reviously characterized 4. (C) 1998 Elsevier Science Ltd. All rights r eserved.