Syntheses, structures and magnetic properties of three 1-D chain metal–nitroxide coordination polymers bridged by e,e-trans-1,4-cyclohexanedicarboxylate

• Published in: Inorganica Chimica Acta Vol. 375; no. 1; pp. 298 - 304
• Main Authors: Wei, Hai-Xia, Chen, Yi-Wen, Gao, Dong-Zhao, Sun, Ya-Qiu, Zhang, Guo-Ying, Xu, Yan-Yan
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.09.2011
• Subjects: 1,4-Cyclohexanedicarboxylic acid; Magnetic property; Metal complex; Nitronyl nitroxide radical; Magnetic property; Metal complex; 1,4-Cyclohexanedicarboxylic acid; Nitronyl nitroxide radical
• ISSN: 0020-1693; 1873-3255
• DOI: 10.1016/j.ica.2011.05.026

Three one-dimensional metal–nitroxide polymers have been synthesized. They all crystallize in neutral 1-D chains where metal–nitroxide units [M(NIT4Py)2(H2O)2] are linked by the linear 1,4-cyclohexanedicarboxylate dianion with the 1,4-chdc only possessing the e,e-trans-conformation. The magnetic measurements show the weak antiferromagnetic interactions between the metal ions and the nitroxides. [Display omitted] ► Three 1-D chain metal-nitroxide complexes have been characterized. ► The 1,4-cyclohexanedicarboxylate only possesses the e,e-trans-conformation. ► The complexes both exhibit weak antiferromagnetic interactions. ► The results are of significance for understanding the magneto-structural correlation. Three new one-dimensional (1-D) chain metal–nitroxide complexes of the formula [M(NIT4Py)2(e,e-trans-1,4-chdc)(H2O)2]n (M=Co(II) 1, Ni(II) 2 and Zn(II) 3; NIT4Py=2-(4′-pyridyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide and 1,4-chdc=1,4-cyclohexanedicarboxylate dianion) have been synthesized and characterized structurally as well as magnetically. The X-ray crystal structure analyses of complexes 1, 2 and 3 reveal that they are isostructural. Three complexes all crystallize in neutral 1-D chains where metal–nitroxide units [M(NIT4Py)2(H2O)2] are linked by the linear 1,4-cyclohexanedicarboxylate dianion. The 1,4-chdc completes the segregation and only possesses the e,e-trans-conformation, although there are both cis- and trans-isomers in the raw material. The magnetic measurements show that complexes 1 and 2 both exhibit weak antiferromagnetic interactions between the metal ions and the nitroxides.