Probing single-chain magnets in a family of linear chain compounds constructed by magnetically anisotropic metal-ions and cyclohexane-1,2-dicarboxylate analogues.
Five new metal-carboxylate chain-based laminated compounds, namely, infinity2[FeII(e,e-trans-1,2-chdc)] (3) (1,2-chdc = cyclohexane-1,2-dicarboxylate), infinity2[NiII(mu-OH2)(e,a-cis-1,2-chdc)] (4), infinity2[CoII(mu-OH2)(1,2-chedc)] (5) (1,2-chedc = cyclohex-1-ene-1,2-dicarboxylate), infinity2[Co5II(mu3-OH)2(OH2)2(1,2-chedc)4] (6), and infinity2[CoII(4-Me-1,2-chdc)] (7) (4-Me-1,2-chdc = trans-4-methylcyclohexane-1,2-dicarboxylate) have been hydrothermally synthesized. In these series of magnetic chain-based compounds, 3 and 7 have the same dimeric paddle-wheel M(II)-carboxylate chain as the previously reported compound, infinity2[CoII(trans-1,2-chdc)] (2). However, compound 3 does not behave as a single-chain magnet (SCM) but simply an alternating ferro-antiferro magnetic chain. Compound 4 has the cis conformation of 1,2-chdc ligand, which leads to a uniform aqua-carboxylate-bridged Ni(II) chain. Such a Ni-O chain exhibits strong antiferromagnetic interactions, leading to a diamagnetic ground state. Compound 5 features a corner-sharing triangular chain, or delta-chain, which is part of a Kagom lattice. However, 5 does not exhibit a spin-frustrated effect but simply spin competition. Compound 6 has a unique pentanuclear CoII cluster, which is further connected by the syn-anti carboxylate into a chain structure. Compound 6 exhibits antiferromagnetic interactions among the Co(II) ions, and no SCM behavior is observed. These results might indicate that the dimeric paddle-wheel Co(II)-carboxylate chain is essential in obtaining SCM behavior in this family of compounds. Although 2 and 7 have very similar SCM behavior, alternating current magnetic studies show that 7 has a higher energy barrier than that of 2. Such behavior is probably caused by the larger anisotropic energy barrier in 7.
Zheng
Yan-Zhen
YZ
MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, School of Chemistry and Chemical Engineering, Sun Yat-Sen University, Guangzhou 510275, China.
Xue
Wei
W
Tong
Ming-Liang
ML
Chen
Xiao-Ming
XM
Zheng
Shao-Liang
SL
D016880:Anisotropy; D018360:Crystallography, X-Ray; D003509:Cyclohexanecarboxylic Acids / Q000737:chemistry*; D003998:Dicarboxylic Acids / Q000737:chemistry*; D008280:Magnetics; D008670:Metals / Q000737:chemistry*; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D055672:Static Electricity
D003509:Cyclohexanecarboxylic Acids; D003998:Dicarboxylic Acids; D008670:Metals; D009942:Organometallic Compounds; C534517:cyclohexane-1,2-dicarboxylic acid