Dinickel(Ii) Complexes with Pyridine-Substituted Bis(Triazolylmethyl)Amine Ligands: Structures and Magnetic Properties
22 Pages Posted: 23 Jul 2020
Coordination behavior of newly prepared bis(triazolylmethyl)amine-type ligands, bis[(1-R-1H-1,2,3-triazol-4-yl)methyl]amine [R = CH2Ph (L1), CH2-2-pyridyl (L2)] and 1-(1-Benzyl-1H-1,2,3-triazol-4-yl)-N-((1-(pyridin-2-ylmethyl)-1H-1,2,3-triazol-4-yl)methyl)methanamine (L3), toward NiII ions was investigated. The reaction of NiCl2·6H2O with the benzyl-substituted bis(triazolylmethyl)amine ligand L1 afforded the mononuclear NiII complex Ni(L1)2Cl2 (1). On the other hand, the dinuclear NiII complexes, [Ni2(L2)2Cl2]Cl2 (2) and [Ni2(L3)2Cl2]Cl2 (3), were obtained when NiCl2·6H2O was reacted with the pyridine-substituted ligands, L2 and L3, respectively. Single-crystal X-ray analysis revealed that two octahedral NiII centers in 2 and 3 are bridged by two triazole rings through nitrogen donors to generate the dinuclear complexes with a syn arrangement. Meanwhile, treatment of Ni(NO3)2 with L2 afforded the related dinickel(II) complex, [Ni2(L2)2(NO3)2](NO3)2 (2'), in which two non-bridging triazole rings and two nitrate ions were positioned in an anti arrangement. Complexes 2 and 3 showed the antiferromagnetic coupling between two NiII centers (S = 1), with J values following the trend: 2' > 2 > 3.
Keywords: Amine-triazole ligands, Bridging triazole, Dinickel complex, Antiferromagnetism
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