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Xia CC, Zhang XY, Zhang CC, Li G, Wei HY, Wang XY. Syntheses and magnetic properties of a bis-bidentate nitronyl nitroxide radical based on triazolopyrimidine and its metal complexes. Dalton Trans 2023. [PMID: 37326416 DOI: 10.1039/d3dt01277h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
A novel bis-bidentate nitronyl nitroxide radical based on triazolopyrimidine, NIT-2-TrzPm (NIT-2-TrzPm = (2-(2'-triazolopyrimidine)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazol-1-oxy-3-oxide)) and six new transition metal complexes of this ligand, namely [M(hfac)2(NIT-2-TrzPm)]·CH2Cl2 (M = Mn (1Mn) and Co (2Co)), [M(hfac)2]2(NIT-2-TrzPm) (M = Mn (3Mn) and Co (4Co)), [Mn(NIT-2-TrzPm)2(MeOH)2](ClO4)2·MeOH (5Mn), and [Co(NIT-2-TrzPm)2(MeOH)2]2(ClO4)4·4MeOH (6Co) were prepared and characterized structurally and magnetically. These complexes can be selectively synthesized by controlling the reaction ratio of M(hfac)2·2H2O to the radical ligand (for 1Mn to 4Co) or using metal perchlorates as the starting materials (for 5Mn and 6Co). Single crystal X-ray crystallographic analyses confirmed that 1Mn and 2Co are isostructural 3d-2p MII-radical complexes, in which the NIT-2-TrzPm radical acts as a terminal bidentate ligand chelating to one 3d ion, while 3Mn and 4Co are isostructural 3d-2p-3d MII-radical-MII complexes with the NIT-2-TrzPm radical acting as a bridging ligand between two 3d ions. For complexes 5Mn and 6Co, two NIT-2-TrzPm ligands from the equatorial positions coordinate with the metal center to form the 2p-3d-2p structures with the axial positions occupied by two methanol molecules. Magnetic analysis on the MnII complexes revealed the existence of a strong antiferromagnetic interaction between the MnII and the NIT radical spin, while weak ferromagnetic coupling for Mn⋯Mn and Rad⋯Rad in the Mn-NIT-Mn and Rad-Mn-Rad spins was confirmed. Interestingly, although the NIT-bridged complexes 3Mn and 4Co possess significantly different magnetic anisotropy, field-induced slow magnetic relaxation can be observed in both complexes, which was assigned to the phonon bottleneck effect for 3Mn and field-induced SMM behavior for 4Co. To the best of our knowledge, 3Mn is the first example of the NIT-bridged binuclear MnII complex undergoing slow magnetic relaxation.
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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.
| | - 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.
| | - Cheng-Cheng Zhang
- State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China.
| | - Gang Li
- State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China.
| | - Hai-Yan Wei
- Jiangsu Key Laboratory of Biofunctional Materials, School of Chemistry and Materials Science, 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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Bonaldi L, Bortoluzzi M, Zacchini S, Pampaloni G, Marchetti F, Biancalana L. Triazine Chalcogenones from Thiocyanate or Selenocyanate Addition to Tetrazine Ligands in Ruthenium Arene Complexes. Inorg Chem 2023; 62:7814-7833. [PMID: 37167024 DOI: 10.1021/acs.inorgchem.3c00459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
The chemistry of 1,2,4,5-tetrazines has attracted considerable interest both from a synthetic and applicative standpoint. Recently, regioselective reactions with alkynes and alkenes have been reported to be favored once the tetrazine ring is coordinated to Re(I), Ru(II), and Ir(III) centers. Aiming to further explore the effects of metal coordination, herein, we unveil the unexplored reactivity of tetrazines with chalcogenocyanate anions. Thus, ruthenium(II) tetrazine complexes, [RuCl{κ2N-3-(2-pyridyl)-6-R-1,2,4,5-tetrazine}(η6-arene)]+ (arene = p-cymene, R = H, [1a]+, R = Me, [1b]+, R = 2-pyridyl, [1c]+; arene = C6Me6, R = H, [1d]+, R = Me, [1e]+; PF6- salts), reacted quantitatively and in mild conditions with M(ECN) salts (M = Na, K, Bu4N; E = O, S, Se). The addition of thiocyanate or selenocyanate to the tetrazine ligand is regioselective and afforded, via N2 release, 1,2,4-triazine-5-chalcogenone heterocycles, the one with selenium being unprecedented. The novel ruthenium complexes [RuCl{κ2N-(2-pyridyl)}{triazine chalcogenone}(η6-arene)] 2a-e (sulfur), 3b, 3d, and 3e (selenium) were characterized by analytical (CHNS analyses, conductivity), spectroscopic (IR, multinuclear and two-dimensional (2D) NMR), and spectrometric (electrospray ionization mass spectrometry (ESI-MS)) techniques. According to density functional theory (DFT) calculations, the nucleophilic attack of SCN- on the tetrazine ring is kinetically driven. Compound 2b is selectively and reversibly mono-protonated on the triazine ring by HCl or other strong acids, affording a single tautomer. When reactions of chalcogenocyanates were performed on the 2,2'-bipyridine (bpy) complex [RuCl(bpy)(η6-p-cymene)]+, the chloride substitution products [Ru(ECN)(bpy)(η6-p-cymene)]+ (E = O, [4]+; E = S, [5]+; E = Se, [6]+) were obtained in 82-90% yields (PF6- salts). Combined spectroscopic data (IR, 1H/13C/77Se NMR) was revealed to be a useful tool to study the linkage isomerism of the chalcogenocyanate ligand in [4-6]+.
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Affiliation(s)
- Lorenzo Bonaldi
- Department of Chemistry and Industrial Chemistry, University of Pisa, Via G. Moruzzi 13, I-56124 Pisa, Italy
| | - Marco Bortoluzzi
- Department of Molecular Sciences and Nanosystems, Ca' Foscari University of Venice, Via Torino 155, I-30175 Mestre, Venezia, Italy
| | - Stefano Zacchini
- Department of Industrial Chemistry "Toso Montanari", University of Bologna, Viale del Risorgimento 4, I-40136 Bologna, Italy
| | - Guido Pampaloni
- Department of Chemistry and Industrial Chemistry, University of Pisa, Via G. Moruzzi 13, I-56124 Pisa, Italy
| | - Fabio Marchetti
- Department of Chemistry and Industrial Chemistry, University of Pisa, Via G. Moruzzi 13, I-56124 Pisa, Italy
| | - Lorenzo Biancalana
- Department of Chemistry and Industrial Chemistry, University of Pisa, Via G. Moruzzi 13, I-56124 Pisa, Italy
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Li Y, Zeng Z, Guo Y, Liu X, Zhang YQ, Ouyang Z, Wang Z, Liu X, Zheng YZ. Synergy of Magnetic Anisotropy and Ferromagnetic Interaction Triggering a Dimeric Cr(II) Zero-Field Single-Molecule Magnet. Inorg Chem 2023; 62:6297-6305. [PMID: 37040590 DOI: 10.1021/acs.inorgchem.2c04359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/13/2023]
Abstract
A novel CrII-dimeric complex, [CrIIN(SiiPr3)2(μ-Cl)(THF)]2 (1), has been successfully constructed using a bulky silyl-amide ligand. Single-crystal structure analysis reveals that complex 1 exhibits a binuclear motif, with a Cr2Cl2 rhombus core, where two equivalent tetra-coordinate CrII centers in the centrosymmetric unit display quasi-square planar geometry. The crystal structure has been well simulated and explored by density functional theory calculations. The axial zero-field splitting parameter (D < 0) with a small rhombic (E) value is unambiguously determined by systematic investigations of magnetic measurements, high-frequency electron paramagnetic resonance spectroscopy, and ab initio calculations. Remarkably, ac magnetic susceptibility data unveil that 1 features slow dynamic magnetic relaxation typical of single-molecule magnet behavior with Ueff = 22 K in the absence of a dc field. This increases up to 35 K under a corresponding static field. Moreover, magnetic studies and theoretical calculations point out that a non-negligible ferromagnetic coupling (FMC) exists in the dimeric Cr-Cr units of 1. The coexistence of magnetic anisotropy and FMC contributes to the first case of CrII-based single-molecule magnets (SMMs) under zero dc field.
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Affiliation(s)
- Yuzhu Li
- State Key Laboratory of High-efficiency Utilization of Coal and Green Chemical Engineering, College of Chemistry and Chemical Engineering, Ningxia University, Yinchuan 750021, China
| | - Zhaopeng Zeng
- State Key Laboratory of High-efficiency Utilization of Coal and Green Chemical Engineering, College of Chemistry and Chemical Engineering, Ningxia University, Yinchuan 750021, China
| | - Yan Guo
- State Key Laboratory of High-efficiency Utilization of Coal and Green Chemical Engineering, College of Chemistry and Chemical Engineering, Ningxia University, Yinchuan 750021, China
| | - Xingman Liu
- State Key Laboratory of High-efficiency Utilization of Coal and Green Chemical Engineering, College of Chemistry and Chemical Engineering, Ningxia University, Yinchuan 750021, China
| | - Yi-Quan Zhang
- Jiangsu Key Laboratory for NSLSCS, School of Physical Science and Technology, Nanjing Normal University, Nanjing 210023, China
| | - Zhongwen Ouyang
- Wuhan National High Magnetic Field Center and School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Zhenxing Wang
- Wuhan National High Magnetic Field Center and School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Xiangyu Liu
- State Key Laboratory of High-efficiency Utilization of Coal and Green Chemical Engineering, College of Chemistry and Chemical Engineering, Ningxia University, Yinchuan 750021, China
| | - Yan-Zhen Zheng
- Frontier Institute of Science and Technology, School of Chemistry and School of Physics, Xi'an Jiaotong University, Xi'an, Shaanxi 710054, China
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Yue Z, Liu J, Baumgarten M, Wang D. Spirobifluorene Mediating the Spin-Spin Coupling of Nitronyl Nitroxide Diradicals. J Phys Chem A 2023; 127:1565-1575. [PMID: 36627248 DOI: 10.1021/acs.jpca.2c06648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
To investigate the mechanism of this spiro conjugation magnetic behavior, we designed and synthesized three diradicals─22'SBF-NN, 44'SBF-NN, and 27SBF-NN. They are bridged by spirobifluorene and nitronyl nitroxide (NN) diradicals as the spin centers. Notably, by SQUID and electron paramagnetic resonance (EPR) zero-field splitting data analyses, the 22'SBF-NN and 27SBF-NN diradicals exhibit intramolecular, distinctly antiferromagnetic (AF) coupling, with 2J(22'SBF-NN)/kB = -5.86 K and 2J(27SBF-NN)/kB = -24.6 K, respectively. The AF of 22'SBF-NN is opposite to that predicted by the spin density alternation rule based on Hund's rule. Diradical intramolecular conjugation coupling bridged by spiro-carbon conjugation is discussed, in which the 22'SBF-NN is smaller than that of 27SBF-NN, corresponding to the room-temperature EPR characterization. This spiro conjugation is weaker than the traditional planar conjugation and generally leads to a weaker spin-spin coupling in the helical biradical molecule. The EPR spectrum of the 44'SBF-NN diradical shows a deformed nine-line curve, indicating intramolecular exchange coupling. The density functional theory calculation gives a very weak coupling constant of 2Jcalc/kB = 0.06 K, with ferromagnetic (FM) interaction as the proof, which is consistent with the spin-polarized prediction. Further analysis of magnetic susceptibility χm and VT-EPR data shows that there is indeed an extremely weak FM interaction in the 44' position diradical. We find the bridge, which is a 44' substituted SBF structure, blocks the conjugation and contains a larger twist in steric hindrance, which also hampers sufficient spin density delocalization, resulting in a much weaker spin coupling interaction. Combined with the analysis of molecular orbital calculation results, the anomalous intramolecular AF coupling mechanism of 22'SBF-NN is further explained.
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Affiliation(s)
- Zheng Yue
- Anhui Key Laboratory of Advanced Building Materials, School of Materials Science and Chemical Engineering, Anhui Jianzhu University, Hefei 230601, China
| | - Jin Liu
- Anhui Key Laboratory of Advanced Building Materials, School of Materials Science and Chemical Engineering, Anhui Jianzhu University, Hefei 230601, China
| | - Martin Baumgarten
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Di Wang
- Anhui Key Laboratory of Advanced Building Materials, School of Materials Science and Chemical Engineering, Anhui Jianzhu University, Hefei 230601, China
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Tang WJ, Wu ST, Bu XM, Zhang HY, Wei XQ, Shao D. Field-induced single-ion magnet behavior in a cobalt(II) coordination polymer constructed by a mixed bipyridyl-tetracarboxylate strategy. Polyhedron 2023. [DOI: 10.1016/j.poly.2022.116175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Qin Y, Wu Y, Luo S, Xi J, Guo Y, Ding Y, Zhang J, Liu X. Modulation of the magnetic dynamics of pentagonal-bipyramidal Co( ii) complexes by fine-tuning the coordination microenvironment. Dalton Trans 2022; 51:17089-17096. [DOI: 10.1039/d2dt02345h] [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
Dynamic magnetic behaviours of a series of Co(ii) SIMs with pentagonal-bipyramidal geometry have been modulated by an alteration of the ligand field effect.
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Affiliation(s)
- Yuanyuan Qin
- State Key Laboratory of High-Efficiency Utilization of Coal and Green Chemical Engineering, College of Chemistry and Chemical Engineering, Ningxia University, Yinchuan 750021, China
| | - Yuewei Wu
- State Key Laboratory of High-Efficiency Utilization of Coal and Green Chemical Engineering, College of Chemistry and Chemical Engineering, Ningxia University, Yinchuan 750021, China
| | - Shuchang Luo
- College of Chemical Engineering, Guizhou University of Engineering Science, Bijie 551700, China
| | - Jing Xi
- State Key Laboratory of High-Efficiency Utilization of Coal and Green Chemical Engineering, College of Chemistry and Chemical Engineering, Ningxia University, Yinchuan 750021, China
| | - Yan Guo
- State Key Laboratory of High-Efficiency Utilization of Coal and Green Chemical Engineering, College of Chemistry and Chemical Engineering, Ningxia University, Yinchuan 750021, China
| | - Yi Ding
- State Key Laboratory of High-Efficiency Utilization of Coal and Green Chemical Engineering, College of Chemistry and Chemical Engineering, Ningxia University, Yinchuan 750021, China
| | - Jun Zhang
- State Key Laboratory of High-Efficiency Utilization of Coal and Green Chemical Engineering, College of Chemistry and Chemical Engineering, Ningxia University, Yinchuan 750021, China
| | - Xiangyu Liu
- State Key Laboratory of High-Efficiency Utilization of Coal and Green Chemical Engineering, College of Chemistry and Chemical Engineering, Ningxia University, Yinchuan 750021, China
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