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Xia CC, Ji WJ, Zhang XY, Miao H, Zhang YQ, Wang XY. Syntheses, structures, and magnetic properties of the lanthanide complexes of imidazole-substituted nitronyl nitroxide biradicals. Dalton Trans 2022; 51:12362-12372. [PMID: 35904351 DOI: 10.1039/d2dt01652d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Two new bis-bidentate imidazole-substituted nitronyl nitroxide biradicals, BNITIm-C2 (BNITIm-C2 = 1,1'-(1,2-ethanediyl)bis(1H-imidazole-2-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazol-1-oxy-3-oxide)) and BNITIm-C4 (BNITIm-C4 = 1,1'-(1,4-butanediyl)bis(1H-imidazole-2-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazol-1-oxy-3-oxide)), and two series of lanthanide complexes, namely [(BNITIm-C2)Ln(NO3)3](MeOH) (Ln = Gd (1Gd) and Tb (2Tb)), (BNITIm-C2)Dy(NO3)3 (3Dy) and (BNITIm-C4)[Ln(hfac)3]2(C7H8)2 (Ln = Gd (4Gd), Tb (5Tb) and Dy (6Dy), hfac = hexafluoroacetylacetonate), have been prepared and characterized structurally and magnetically. Single crystal X-ray crystallographic analyses revealed that complexes 1Gd-3Dy exhibit 1D chain structures where the Ln(NO3)3 units are bridged by the BNITIm-C2 bis-bidentate biradical, while complexes 4Gd-6Dy exhibit binuclear structures with two Ln(hfac)3 units bridged by the BNITIm-C4 biradical. The bulky hfac anions prohibit the further coordination of LnIII to another NIT ligand and the formation of a similar 1D chain structure. Due to the very long intra- and intermolecular distances of the spin centers, complexes 1Gd-3Dy can be magnetically regarded as an isolated 2p-4f-2p tri-spin system while complex 4Gd-6Dy can be regarded as an isolated 2p-4f bi-spin system. Magnetic analyses on the two GdIII compounds revealed the ferromagnetic GdIII-NIT interactions and antiferromagnetic NIT-NIT interactions through the GdIII ion in 1Gd. Alternating-current (ac) magnetic susceptibility investigations revealed that complex 5Tb exhibits the typical SMM behavior under a zero dc field while complex 6Dy was proved to be a field-induced SMM. Ab initio calculations were performed on complexes 2Tb and 5Tb to understand their magnetic anisotropy together with their different magnetic dynamics.
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Affiliation(s)
- Cheng-Cai Xia
- State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China.
| | - Wen-Jie Ji
- State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China.
| | - Xin-Yu Zhang
- State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China.
| | - Hao Miao
- State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China.
| | - Yi-Quan Zhang
- Jiangsu Key Laboratory for NSLSCS, School of Physical Science and Technology, Nanjing Normal University, Nanjing 210023, China.
| | - Xin-Yi Wang
- State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China.
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