Synthesis, crystal structures and magnetic properties of tetrakis(12-carboxylate)-bridged dimeric gadolinium(III) complexes

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Ming- Liang Tong,
Zhong- Yuan Zhou
Yu-' Luan Wu
Xiao- Ming Chen

Abstract

Four dimeric gadolinium(III) complexes, [Gd2(pybet)4(H20)8](C104)6 (1), [Gc12(pybet)4(phen)4](C104)6.3H20 (3), [Gd2(pybet)6(phen)2(H20)2J(C104)6.2H20 (4), and [Gd2(ppbet)6(bpy)2](C104)6.3H20 (5) (pybet = C51-15N+CH2CO2-, ppbet = C5H5N+CH2CH2CO2, phen = 1,10-phenanthroline, bpy-. 2,2'-bipyridine) have been prepared and structurally characterized by X-ray crystallography. The complexes comprise discrete quadruply carboxylate-0,0' bridged [Gd2(carboxylate)4]6+ dimeric cores in which each metal atom is further coordinated by four terminal aqua ligands, one monodentate pybet carboxylate group and three aqua ligands, two phen ligands and a bpy ligand and a chelate ppbet carboxylate group for 1, 3, 4 and 5, respectively. In the four complexes, the metal atoms all adopt distorted square­antiprismatic coordination geometries. The variable-temperature (4­300 K) magnetic susceptibility of 5 has been determined and the observed susceptibility data were fitted to the theoretical magnetic equation. The exchange integral J was found to be 0.037 cm-', indicating very weak ferromagnetic spin-exchange interaction between the pair of Gd(III) ions in the dimers.


Four dimeric gadolinium(III) complexes, [Gd2(pybet)4(H20)8](C104)6 (1), [Gc12(pybet)4(phen)4](C104)6.3H20 (3), [Gd2(pybet)6(phen)2(H20)2J(C104)6.2H20 (4), and [Gd2(ppbet)6(bpy)2](C104)6.3H20 (5) (pybet = C51-15N+CH2CO2-, ppbet = C5H5N+CH2CH2CO2, phen = 1,10-phenanthroline, bpy-. 2,2'-bipyridine) have been prepared and structurally characterized by X-ray crystallography. The complexes comprise discrete quadruply carboxylate-0,0' bridged [Gd2(carboxylate)4]6+ dimeric cores in which each metal atom is further coordinated by four terminal aqua ligands, one monodentate pybet carboxylate group and three aqua ligands, two phen ligands and a bpy ligand and a chelate ppbet carboxylate group for 1, 3, 4 and 5, respectively. In the four complexes, the metal atoms all adopt distorted square­antiprismatic coordination geometries. The variable-temperature (4­300 K) magnetic susceptibility of 5 has been determined and the observed susceptibility data were fitted to the theoretical magnetic equation. The exchange integral J was found to be 0.037 cm-', indicating very weak ferromagnetic spin-exchange interaction between the pair of Gd(III) ions in the dimers.

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How to Cite
Liang Tong, M.-., Yuan Zhou, Z.-., Luan Wu, Y.- ’, & Ming Chen, X.-. (1996). Synthesis, crystal structures and magnetic properties of tetrakis(12-carboxylate)-bridged dimeric gadolinium(III) complexes. Malaysian Journal of Science, 17(2), 87–100. Retrieved from http://jice.um.edu.my/index.php/MJS/article/view/9421
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