INTERACTION OF MORPHOLINE AND THIOMORPHOLINE WITH MOLECULAR DIIODINE - X-RAY CRYSTAL-STRUCTURE OF MORPHOLINIUM TRIIODIDE

The reactions between the donors morpholine (1) and thiomorpholine (2) with I-2 in low polar solvents (C6H6, CHCl3, CH2Cl2) and different do nor/I-2 concentration ratios (1:1, 1:2, 1:3) yield solids of stoichiom etry 1 . I-2, 1H(+)I(3)(-), 1H(+)I(5)(-), 2 . I-2, and 2H+I-3(-). Crys tals suitable for X-ray structure determination have been obtained onl y for 1H+I-3(-). All the solids were characterized by FT-Raman and FT- IR spectroscopies in the region ofthe v(I-I) frequencies. Studies in s olution have been carried out on each of the reactions between 1, 2, a nd N-methylmorpholine (3) with I-2. The formation constants of the 1:1 adducts of 2 and 3 determined at 20 degrees C by UV-visible spectrosc opy are 8500 and 8400 dm(3) mol(-1), respectively. IR spectroscopy sho ws that I-2 binds the nitrogen of 1 and 2 both in axial and equatorial positions. Further FT-Raman and C-13 NMR spectroscopies support the n ature of weak adducts berween 1 (2) and the molecular diiodine in solu tion. (C) 1997 John Wiley & Sons, Inc.