Optically actuating ultra-stable radicals in a large π-conjugated ligand constructed photochromic complex

• DOI: 10.1007/s11426-020-9891-4
• Publication Date: 2021-01-20T16:03:24Z
• Authors: Ji-Xiang Hu; Xiao-Fan Jiang; Yu-Juan Ma; Xue-Ru Liu; Bang-Di Ge; A-Ni Wang; Qi Wei; Guo-Ming Wang
• Keywords: 01 natural sciences; 0104 chemical sciences

Producing ultra-stabilized radicals via light irradiation has raised considerable concern but remains a tremendous challenge in functional materials. Herein, optically actuating ultra-stable radicals are discovered in a sterically encumbered and large π-conjugated tri(4-pyridyl)-1,3,5-triazine (TPT) ligands constructed photochromic compound Cu3(H-HEDP)2TPT2·2H2O ( QDU-12 ; HEDP=hydroxyethylidene diphosphonate). The photogeneration of TPT• radicals is the photoactive behavior of electron transfer from HEDP motifs to TPT units. The ultra-long-lived radicals are contributed from strong interchain π-π interactions between the large π-conjugated TPT components, with the radical lifetime maintained for about 18 months under ambient conditions. Moreover, the antiferromagnetic couplings between TPT• radicals and Cu2+ ions plummeted the demagnetization to 35% of its original state after light irradiation, showing the largest room temperature photodemagnetization in the current radical-based photochromic materials.