title: Spin crossover properties of enantiomers, co-enantiomers, racemates, and co-racemates.
abstract: Through multi-component self-assembly of chiral phenylethylamine, 1-alkyl-2-imidazolecarboxaldehyde and iron(ii) ions, two couples of enantiomeric iron(ii) complexes , , and with the formula of fac-Λ or Δ-[Fe(L)3](2+)(L = R or S-1-phenyl-N-(1-alkyl-1H-imidazol-2-ylmethylene)ethanamine) have been designed and synthesized as building blocks. Further binary cocrystallization of the prefabricated enantiomers enabled us to construct spin crossover co-enantiomers and , racemates and , and co-racemate . Compared with in a high spin state and with spin crossover at 291 K, the co-enantiomers exhibited gradual spin crossover at a higher temperature of 301 K, and the racemic alloys showed hysteresis loops induced by desolvation above room temperature. It was demonstrated that molecular chirality could be used effectively for stereochemical engineering of spin crossover materials. In addition, crystal packing, intramolecular π-π stacking, intermolecular C-Hπ interactions and solvent effects were elucidated to be responsible for the distinct spin crossover properties. This collective structural and magnetic study not only enriched the spin crossover library, but also provided a full comparison of optically pure, homochiral, and racemic materials with similar molecular structures.
authors.affiliation: The Key Laboratory of Food Colloids and Biotechnology Ministry of Education, School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122, China. zhiguogu@jiangnan.edu.cn.
authors.forename: Long-Fang
authors.initials: LF
authors.lastname: Qin
authors.affiliation: The Key Laboratory of Food Colloids and Biotechnology Ministry of Education, School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122, China. zhiguogu@jiangnan.edu.cn.
authors.forename: Chun-Yan
authors.initials: CY
authors.lastname: Pang
authors.affiliation: The Key Laboratory of Food Colloids and Biotechnology Ministry of Education, School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122, China. zhiguogu@jiangnan.edu.cn.
authors.forename: Wang-Kang
authors.initials: WK
authors.lastname: Han
authors.affiliation: The Key Laboratory of Food Colloids and Biotechnology Ministry of Education, School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122, China. zhiguogu@jiangnan.edu.cn.
authors.forename: Feng-Li
authors.initials: FL
authors.lastname: Zhang
authors.affiliation: The Key Laboratory of Food Colloids and Biotechnology Ministry of Education, School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122, China. zhiguogu@jiangnan.edu.cn.
authors.forename: Lei
authors.initials: L
authors.lastname: Tian
authors.affiliation: The Key Laboratory of Food Colloids and Biotechnology Ministry of Education, School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122, China. zhiguogu@jiangnan.edu.cn.
authors.forename: Zhi-Guo
authors.initials: ZG
authors.lastname: Gu
authors.affiliation: The Key Laboratory of Eco-textiles of Ministry of Education, College of Textiles and Clothing, Jiangnan University, Wuxi 214122, China.
authors.forename: Xuehong
authors.initials: X
authors.lastname: Ren
authors.affiliation: The Key Laboratory of Food Colloids and Biotechnology Ministry of Education, School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122, China. zhiguogu@jiangnan.edu.cn.
authors.forename: Zaijun
authors.initials: Z
authors.lastname: Li