Chemical Physics Letters, Vol.648, 189-194, 2016
Geometrical structure of meta-xylylene based symmetric polyradicals and their magnetic nature: A density functional study
Quantum chemical investigations on symmetrical polyradicals of meta-xylylene chains are done using unrestricted DFT - broken symmetry formalism, to determine whether the polymers are quasi-linear or helical, and their possible magnetic characteristics. As more radical centers are added, successively placed phenyl rings become twisted in the same direction to form a coiled chain. Each polyradical possesses a high-spin ground state with large adiabatic as well as vertical coupling constants. The adiabatic coupling constant exponentially decays with an increasing number of radical centers. Also, the Heisenberg-Dirac-Van Vleck coupling constants are generally large. The polymers are predicted to be very strong paramagnets. (C) 2016 Elsevier B.V. All rights reserved.