Structural Organization of Symmetrical Dialkylthiuran Disulfides and Their Cyclic Analogs: X-Ray Diffraction and CP/MAS (~13C, ~15N) NMR Studies

摘要

High-resolution ~13C and ~15N solid-state NMR spectra were recorded for seven crystalline tetraalkyl-thiuram disulfides and their cyclic analogs of the general formula [R_2NC(S)S]_2 (where R = CH_3, C_2H_5, C_3H_7, and i-C_3H_7 or R_2 = (CH_2)_5, (CH_2)_6, and (CH2)_4O. The ~15N and ~13C NMR resonances were assigned to the particular atoms in the compounds studied. Different isotropic ~15N chemical shifts for both dialkyldithiocarbamato groups were interpreted while considering the inductive effects of the alkyl substituents combined with the mesomeric effect of the dithiocarbamato group. X-ray diffraction data were used to refine the molecular structure of bis(cyclohexamethylene)thiuram disulfide and to quantitatively characterize the conformations of the seven-membered N(CH_2)_6 heterocycles.