Reversible on-off switching of spin-crossover behavior via photochemical [2+2] cycloaddition reaction

• 作者: Long-Fei Wang Bang-Heng Lv Feng-Tai Wu Guo-Zhang Huang Ze-Yu Ruan Yan-Cong Chen Min Liu Zhao-Ping Ni Ming-Liang Tong
• 来源期刊: 中国科学：化学（英文版）
• 年，卷（期）: 2022,（1）
• 所属期刊栏目: ARTICLES
• 页码范围: 120-127
• 页数: 8页
• 语种: 英文

摘要

Herein,we report the first example showing the reversible on-off switching of spin-crossover (SCO) property by solid state photochemical[2+2]reaction.The ultraviolet (UV) light-induced[2+2]cycloaddition reaction of 3-spy ligands in a two-dimensional (2D) Hofmann-type framework[Fe(3-spy)2{Pd(CN)4}](1,3-spy=3-styrylpyridine),which shows a hysteretic two-step SCO behavior,gives a 3D Hofmann-type framework[Fe(rctt-3-ppcb){Pd(CN)4}](2,rctt-3-ppcb=rctt-l,3-bis(3-pyridyl)-2,4-bis(phenyl)cyclobutane,r=reference group,c=cis and t=-trans) accompanied with the disappearing of SCO properties.Moreover,upon heating at 250 ℃ for 12 h,the rctt-3-ppcb ligand in 2 could be partially dedimerized to 3-spy with 68％ completion through single-crystal-to-single-crystal (SCSC) transformation,giving the annealing complexes[Fe(3-spy)1.36(rctt-3-ppcb)0.32 {Pd(CN)4}](3)which display an incomplete SCO behavior.The 2 (=) 3 interconversion is successfully achieved via continuous UV irradiation and thermal annealing,demonstrating the effectiveness of photochemical[2+2]reaction on switching on-off SCO properties.