Radical-Based Coordination Polymers as a Platform for Magnetoluminescence.

ABSTRACT

Spin-correlated electronic and magnetic properties of organic radicals have been developed, but luminescence properties, based on interplay with spins, have rarely been reported. The effect of magnetic fields on luminescence (i.e., magnetoluminescence) is a rare example of such properties, observed to date only in radicals dispersed in host matrices. We now report a novel method for achieving radical magnetoluminescence involving radical-based coordination polymers (CPs). The luminescence properties of the bis(3,5-dichloro-4-pyridyl)(2,4,6-trichlorophenyl)methyl (bisPyTM) and tris(3,5-dichloro-4-pyridyl)methyl (trisPyM) radicals and their 1D and 2D ZnII CPs were investigated. Although solid-state emissions of bisPyTM and trisPyM were not affected significantly by external magnetic fields at 4.2 K, those of CPs were greatly modulated. Studies of the crystal structures, magnetic properties, and the temperature-dependence and time-resolved properties of the magnetoluminescence indicate that the reduction of radical-radical interactions in CPs would be a key method for achieving magnetoluminescence.