title: Magnetostructural relationship for μ2-phenoxido bridged ferric dimers.
abstract: Three Fe(iii) dimers, [Fe2(L-H)2]·2CH3CN (1), [Fe2(L-OCH3)2] (2) and [Fe2(L-OC2H5)2]·2CH3CN (3), containing the pentadentate O,N,N,O,O-donor Schiff-base ligands with variable size pendants, were synthesized and structurally characterized. The three ligands were generated in situ from 2-(iminomethyl)phenol, 2-methoxy-6-(iminomethyl)phenol and 2-ethoxy-6-(iminomethyl)phenol, respectively. All three crystal structures contain centrosymmetric dimers of edge-sharing octahedra of Fe(iii) ions through a pair of μ2-phenoxido bridges. The exchange coupling is ferromagnetic for 1 (J = +0.47(1) cm-1, ∠Fe-O-Fe = 98.02°) and 2 (J = +0.86(1) cm-1, ∠Fe-O-Fe = 97.17°), but antiferromagnetic for 3 (J = -0.72(1) cm-1, ∠Fe-O-Fe = 98.53°), which are correlated by high-field electron paramagnetic resonance revealing moderate magneto-anisotropy of D = -0.24(3) cm-1, E = 0.08(1) cm-1for 1, D = -0.38(1) cm-1, E = 0.11(1) cm-1for 2, and D = 0.30(3) cm-1, E = 0.02(1) cm-1for 3. The exchange couplings were further estimated by DFT calculations, which gave the finest Fe-O-Fe angle of 97.83° for the ferromagnetic-antiferromagnetic crossover.
authors.affiliation: State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210023, P. R. China. zuojl@nju.edu.cn.
authors.forename: Fei
authors.initials: F
authors.lastname: Yu
authors.affiliation: State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210023, P. R. China. zuojl@nju.edu.cn.
authors.forename: Zi-Heng
authors.initials: ZH
authors.lastname: Cao
authors.affiliation: State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210023, P. R. China. zuojl@nju.edu.cn.
authors.forename: Jing-Yuan
authors.initials: JY
authors.lastname: Ge
authors.affiliation: Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China. zxwang@hust.edu.cn.
authors.forename: Yi-Chen
authors.initials: YC
authors.lastname: Sun
authors.affiliation: Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China. zxwang@hust.edu.cn.
authors.forename: Zhong-Wen
authors.initials: ZW
authors.lastname: Ouyang
authors.affiliation: State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210023, P. R. China. zuojl@nju.edu.cn.
authors.forename: Jing-Lin
authors.identifier: http://orcid.org/0000-0003-1219-8926
authors.initials: JL
authors.lastname: Zuo
authors.affiliation: Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China. zxwang@hust.edu.cn.
authors.forename: Zhenxing
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Institut de Chimie de Strasbourg, Université de Strasbourg, CNRS-UMR 7177, 4 rue Blaise Pascal, 67008 Cedex Strasbourg, France.
authors.forename: Mohamedally
authors.initials: M
authors.lastname: Kurmoo