Stable Triarylmethyl Radicals and Cobalt(II) Ions Based 1D/2D Coordination Polymers

Abstract

The incorporation of organic radicals into coordination polymers was considered as a promising strategy to promote metal-ligand exchange interactions, but there are only a very limited number of stable organic radical-based ligands that can serve well such a purpose. Herein, we report two new tris(2,4,6-trichlorophenyl)methyl (TTM) radical-based ligands L1 and L2 with two and three imidazole substituents, respectively. The imidazole unit serves as a coordination site and it can also stabilize the TTM radical by intramolecular donor-acceptor interaction. Coordination of L1 and L2 with cobalt(II) ions gave the corresponding one-(CoCP-1) and two-dimensional (CoCP-2) coordination polymers, the structures of which were confirmed by X-ray crystallographic analysis. Magnetic measurements and theoretical calculations suggest antiferromagnetic coupling between the paramagnetic cobalt(II) ions and the radical ligands. Our study provides a rational design for stable organic radical-based ligands and further demonstrated the feasibility of a metalradical approach toward magnetic materials.

Iridium(III) Complex Radical and Corresponding Ligand Radical Functionalized by a Tris(2,4,6-trichlorophenyl)methyl Unit: Synthesis, Structure, and Photophysical Properties

“…It is worth noting that among these metal complexes, Au­(I) complexes − have relatively good optical properties. However, there are relatively few reports on the TTM- or PTM-based metal complex radicals − and almost no studies on their optical properties. Based on this, it is worth looking forward to introducing the TTM unit into other luminescent metal complexes and studying how the TTM luminescence moiety interacts with the metal luminescence center.…”