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Single‐crystal electron‐spin resonance study of the 4‐phenyl‐1,2,3,5‐dithiadiazolyl radical
Author(s) -
Lee F. L.,
Preston K. F.,
Williams A. J.,
Sutcliffe L. H.,
Banister A. J.,
Wait S. T.
Publication year - 1989
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.1260271210
Subject(s) - chemistry , unpaired electron , hyperfine structure , electron paramagnetic resonance , crystallography , perpendicular , crystal (programming language) , spin (aerodynamics) , impurity , ring (chemistry) , atomic orbital , spectroscopy , electron , nuclear magnetic resonance , radical , atomic physics , geometry , physics , organic chemistry , mathematics , quantum mechanics , computer science , thermodynamics , programming language
Single crystals of 4‐phenyl‐1,2,3,5‐dithiadiazolium trithiatriazinide, prepared by the reduction of S 5 N 5 + AlCl 4 − in SO 2 with, contain a trace paramagnetic impurity which is shown by EPR spectroscopy to be the dithiadiazolyl free radical. The g and 14 N hyperfine tensors of the radical were deduced from measurements made throughout three mutually orthogonal planes of crystallographically aligned specimens: g = (2.0011, 2.0075, 2.0197); 14 N(2) = (37.1, 11.3, 3.4 MHz.). Within experimental error, the two nitrogen hyperfine interaction tensors are collinear and have their maximum principal value aligned parallel to g min and perpendicular to the plane of the host cation. The results are interpreted in terms of a planar π‐radical which substitutes for the planar host cation, and which has considerable unpaired spin density in N(2p x ) atomic orbitals directed perpendicular to the heterocyclic ring.