174
H.-R. Zhao et al. / Journal of Molecular Structure 930 (2009) 167–175
Fig. 11. (a) Charge distributions (Atomic charges with hydrogens summed into heavy atoms and the sum of Mulliken charges = 1.00000) and (b) spin distributions in the
radical cation of 1.
ing interactions between the neighboring imidazoline rings in the
crystals of 1–3. Therefore, the magnetic coupling interactions be-
and 20490218). Ren thanks Dr. Chuan-Jiang Hu for reading the
manuscript.
tween the neighboring radicals are not available through
p-orbi-
tal overlaps of imidazoline rings, and weak spin polarization
effect should play an important role in controlling the magnetic
coupling character between neighboring radicals, which is in
agreement with the observations that three radical compounds
exhibit weakly antiferromagnetic coupling nature.
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Acknowledgements
Authors thank Science and Technology Department of Jiangsu
Province and the Nature Science Foundation of China for financial
support (Grant Nos. BK2007184, 10774076, 20871068, 20771056