title: Coligand modifications fine-tuned the structure and magnetic properties of two triple-bridged azido-Cu(ii) chain compounds exhibiting ferromagnetic ordering and slow relaxation.
abstract: Employing two benzoate derivatives with different numbers of non-coordinated fluoro-substituents, 2-fluorobenzoic acid (2-Hfba) and 2,6-difluorobenzoic acid (2,6-Hdfba), two new azido-copper coordination polymers, [Cu(2-fba)(N3)(CH3OH)]n(1) and [Cu(2,6-dfba)(N3)(CH3OH)]n(2), have been successfully isolated, and then structurally and magnetically investigated. Single crystal structure analysis demonstrates that the metal cations in the two resulting compounds are connected by the alternating triple-bridge of μ-1,1-azido, syn,syn-carboxylate and μ2-methanol, contributing to analogously linear 1D Cu(ii) chain-like motifs with slightly different intrachain and interchain geometric parameters. The fine-tuned structures lead to variant magnetic properties in the two title compounds. Although a dominant ferromagnetic coupling between adjacent Cu(ii) ions within each chain due to the counter-complementarity of the multiple superexchange pathways is observed in both compounds, the interesting plots of magnetic ordering and slow magnetic relaxation, which are rare in most of the reported azido-Cu(ii) architectures, only occur in compound 1, while 2 behaves as an antiferromagnet consisting of ferromagnetic Cu(ii) chains. The heat-capacity experiments further emphasize the characteristic long-range ferromagnetic ordering in 1 and the typical behavior of antiferromagnets in 2. Moreover, density functional theory (DFT) calculations (using different methods and basis sets) have been performed on both compounds to obtain the qualitatively theoretical interpretation of the magnetic behaviors.
authors.affiliation: College of Chemistry and Chemical Engineering, State Key Laboratory Cultivation Base of Natural Gas Conversion, Ningxia University, Yinchuan 750021, China. xiangyuliu432@126.com.
authors.forename: Xiangyu
authors.identifier: http://orcid.org/0000-0001-8864-3411
authors.initials: X
authors.lastname: Liu
authors.affiliation: College of Chemistry and Chemical Engineering, State Key Laboratory Cultivation Base of Natural Gas Conversion, Ningxia University, Yinchuan 750021, China. xiangyuliu432@126.com.
authors.forename: Feifei
authors.initials: F
authors.lastname: Li
authors.affiliation: College of Chemistry and Chemical Engineering, State Key Laboratory Cultivation Base of Natural Gas Conversion, Ningxia University, Yinchuan 750021, China. xiangyuliu432@126.com.
authors.forename: Xiaohui
authors.initials: X
authors.lastname: Ma
authors.affiliation: College of Chemistry and Chemical Engineering, State Key Laboratory Cultivation Base of Natural Gas Conversion, Ningxia University, Yinchuan 750021, China. xiangyuliu432@126.com and Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi'an 710069, China. sanpingchen@126.com.
authors.forename: Peipei
authors.initials: P
authors.lastname: Cen
authors.affiliation: School of Chemical Engineering, Guizhou University of Engineering Science, Bijie, 551700, China.
authors.forename: Shuchang
authors.initials: S
authors.lastname: Luo
authors.affiliation: Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China. shiquan@dicp.ac.cn.
authors.forename: Quan
authors.initials: Q
authors.lastname: Shi
authors.affiliation: College of Chemistry and Chemical Engineering, State Key Laboratory Cultivation Base of Natural Gas Conversion, Ningxia University, Yinchuan 750021, China. xiangyuliu432@126.com.
authors.forename: Shenru
authors.initials: S
authors.lastname: Ma
authors.affiliation: College of Chemistry and Chemical Engineering, State Key Laboratory Cultivation Base of Natural Gas Conversion, Ningxia University, Yinchuan 750021, China. xiangyuliu432@126.com.
authors.forename: Yuewei
authors.initials: Y
authors.lastname: Wu
authors.affiliation: College of Chemistry and Chemical Engineering, State Key Laboratory Cultivation Base of Natural Gas Conversion, Ningxia University, Yinchuan 750021, China. xiangyuliu432@126.com.
authors.forename: Chengcheng
authors.initials: C
authors.lastname: Zhang
authors.affiliation: College of Chemistry and Chemical Engineering, State Key Laboratory Cultivation Base of Natural Gas Conversion, Ningxia University, Yinchuan 750021, China. xiangyuliu432@126.com.
authors.forename: Zhao
authors.initials: Z
authors.lastname: Xu
authors.affiliation: College of Chemistry and Chemical Engineering, State Key Laboratory Cultivation Base of Natural Gas Conversion, Ningxia University, Yinchuan 750021, China. xiangyuliu432@126.com.
authors.forename: Weiming
authors.initials: W
authors.lastname: Song
authors.affiliation: Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi'an 710069, China. sanpingchen@126.com.
authors.forename: Gang
authors.initials: G
authors.lastname: Xie
authors.affiliation: Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi'an 710069, China. sanpingchen@126.com.
authors.forename: Sanping
authors.identifier: http://orcid.org/0000-0002-6851-7386
authors.initials: S
authors.lastname: Chen