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Molecular orbital studies on the spin states of nitroxide species: Bis‐ and trisnitroxymetaphenylene, 1,1‐bisnitroxyphenylethylene, and 4,6‐dimethoxy‐1,3‐dialkylnitroxy‐benzenes
Author(s) -
Trindle Carl,
Nath Datta Sambhu
Publication year - 1996
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/(sici)1097-461x(1996)57:4<781::aid-qua26>3.0.co;2-1
Subject(s) - planarity testing , steric effects , decoupling (probability) , spin (aerodynamics) , nitroxide mediated radical polymerization , chemistry , ground state , planar , computational chemistry , conjugated system , molecular orbital , chemical physics , molecule , quantum mechanics , physics , crystallography , thermodynamics , stereochemistry , organic chemistry , polymerization , polymer , computer science , computer graphics (images) , radical polymerization , control engineering , engineering
Abstract We describe by approximate MO calculation a number of species for which high spin states are either the ground state or lie very low in energy. These are models for the spin coupling in projected ferromagnetic organic materials. The theory guiding their construction is based on planar conjugated systems, while experimentally realized systems are often far from planarity. We can by appeal to steric decoupling explain the failure of the prediction that methoxy subsitution on metaphenylene‐coupled nitroxides should stabilize the triplet. However, we find in general that the qualitative rules derived from discussion of planar systems are robust; drastic departures from planarity are required before they lose their value. © 1996 John Wiley & Sons, Inc.