ISSN:
0030-4921
Keywords:
Chemistry
;
Analytical Chemistry and Spectroscopy
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
13C NMR spin-lattice relaxation times (T1) and nuclear Overhauser enhancements (η) were measured for dithiarsolanes. The contributions of dipolar (T1DD) and spin-rotation (T1SR) mechanisms were determined. The T1 data were analysed to obtain information on the relative order of magnitude of the internal motion rates. The calculations were based on the isotropic, with internal rotation about the As—Ph bond, model of reorientation. In cis, trans-2-phenyl-4-methyl-1,3,2-dithiarsolane, the internal rotation of the phenyl ring is c. three times faster than overall molecular reorientation. The internal motion of the arsolane ring is slightly slower than the phenyl ring rotation. The rotation of the methyl groups in the compounds appears to be considerably hindered, with rotation energy barriers of c. 10 kJ mol-1. In contrast to the situation in the 4-methyldithiarsolane, the internal motion of the arsolane ring is twice as fast as the internal rotation of the phenyl ring for the methyl-unsubstituted analogue, 2-phenyl-1,3,2-dithiarsolane.
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/mrc.1270170412
Permalink
