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Peng M, Wu XF, Wang LX, Chen SH, Xiang J, Jin XX, Yiu SM, Wang BW, Gao S, Lau TC. Slow magnetic relaxation in high-coordinate Co(II) and Fe(II) compounds bearing neutral tetradentate ligands. Dalton Trans 2021; 50:15327-15335. [PMID: 34636819 DOI: 10.1039/d1dt02575a] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The first-row transition metal compounds, [MII(L1)2](ClO4)2 (M = Ni (1); Co (2)), have been prepared by treatment of a neutral tetradentate ligand (L1 = N2,N9-dibutyl-1,10-phenanthroline-2,9-dicarboxamide) with metal perchlorate salts in MeOH. Both compounds have been structurally characterized by X-ray crystallography and it was found that the coordination numbers are 6 and 7, respectively. The reaction of 6,6'-bis(2-tbutyl-tetrazol-5-yl)-2,2'-bipyridine (L2) with hydrated FeII(ClO4)2 afforded a 8-coordinate Fe(II) compound, [FeII(L2)2](ClO4)2 (3); however its reaction with hydrated CoII(ClO4)2 resulted in 6-coordinate [CoII(L2)2](ClO4)2. It is interesting to observe field-induced slow magnetic relaxation in the 7-coordinate Co(II) compound 2 and 8-coordinate Fe(II) compound 3, which further supports the validity of designing high coordination number compounds as single-molecule magnets. Direct current magnetic studies demonstrate that 2 has a very large positive D value (56.2 cm-1) and a small E value (0.66 cm-1), indicating easy plane magnetic anisotropy. Consistent with the larger D value, an effective spin-reversal barrier of Ueff = 100 K (71.4 cm-1) is obtained, which is the highest value reported for 7-coordinate Co(II) complexes with a pentagonal bipyramidal geometry. In contrast, 8-coordinate Fe(II) compound 3 exhibits uniaxial magnetic anisotropy.
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Affiliation(s)
- Min Peng
- College of Chemistry and Environmental Engineering, Yangtze University, Jingzhou 434020, HuBei, P. R. China.
| | - Xiao-Fan Wu
- State Key Laboratory of Rare Earth Materials Chemistry and Applications and PKU-HKU Joint Laboratory on Rare Earth Materials and Bioinorganic Chemistry, Peking University, Beijing 100871, P. R. China.
| | - Li-Xin Wang
- College of Chemistry and Environmental Engineering, Yangtze University, Jingzhou 434020, HuBei, P. R. China.
| | - Si-Huai Chen
- School of Chemistry and Environmental Engineering, Wuhan Institute of Technology, Wuhan 430073, P. R. China
| | - Jing Xiang
- College of Chemistry and Environmental Engineering, Yangtze University, Jingzhou 434020, HuBei, P. R. China.
| | - Xin-Xin Jin
- State Key Laboratory of Rare Earth Materials Chemistry and Applications and PKU-HKU Joint Laboratory on Rare Earth Materials and Bioinorganic Chemistry, Peking University, Beijing 100871, P. R. China.
| | - Shek-Man Yiu
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong, P. R. China.
| | - Bing-Wu Wang
- State Key Laboratory of Rare Earth Materials Chemistry and Applications and PKU-HKU Joint Laboratory on Rare Earth Materials and Bioinorganic Chemistry, Peking University, Beijing 100871, P. R. China.
| | - Song Gao
- State Key Laboratory of Rare Earth Materials Chemistry and Applications and PKU-HKU Joint Laboratory on Rare Earth Materials and Bioinorganic Chemistry, Peking University, Beijing 100871, P. R. China. .,South China University of Technology, P. R. China
| | - Tai-Chu Lau
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong, P. R. China.
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Acharya J, Ahmed N, Flores Gonzalez J, Kumar P, Cador O, Singh SK, Pointillart F, Chandrasekhar V. Slow magnetic relaxation in a homo dinuclear Dy(iii) complex in a pentagonal bipyramidal geometry. Dalton Trans 2020; 49:13110-13122. [PMID: 32930277 DOI: 10.1039/d0dt02881a] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
We hereby report a dinuclear Dy(iii) complex, [Dy(LH3)Cl2]2·2Et2O (1) (LH4 = 2,3-dihydroxybenzylidene)-2-(hydroxyimino)propanehydrazide where both the metal centres are in a pentagonal bipyramidal (PBP) geometry with the axial positions being occupied by negatively charged Cl- ions. The complex as well as it's 10% diluted analogue (110) do not show zero-field SMM behaviour. However, in the presence of small optimum dc fields the slow relaxation of magnetization was displayed. The effective energy barrier for 110 at 800 Oe of applied field was extracted as 83(17) K with τ0 = 2(4) × 10-12 s. Through a combined experimental and ab initio electronic structure calculations studies we have thoroughly analysed the role of the ligand field around the Dy(iii), present in pentagonal bipyramidal geometry, in contributing to the slow relaxation of magnetization.
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Affiliation(s)
- Joydev Acharya
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur-208016, India.
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Su QQ, Fan K, Huang XD, Xiang J, Cheng SC, Ko CC, Zheng LM, Kurmoo M, Lau TC. Field-induced slow magnetic relaxation in low-spin S = 1/2 mononuclear osmium(v) complexes. Dalton Trans 2020; 49:4084-4092. [PMID: 32134093 DOI: 10.1039/d0dt00295j] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Photochemical reactions of (PPh4)[OsVI(N)(L)(CN)3] (NO2-OsN) with piperidine and pyrrolidine afforded two osmium(v) hydrazido compounds, (PPh4)[OsV(L)(CN)3(NNC5H10)] ([PPh4]1) and (PPh4)[OsV(L)(CN)3(NNC4H8)] ([PPh4]2), respectively. Their structures consist of isolated, mononuclear distorted octahedral osmium anions that are well-separated from each other by PPh4+. Their low spin S = 1/2 and L = 1 ground state was confirmed by magnetometry and DFT calculations. Interestingly, both compounds exhibit slow magnetic relaxation under a bias dc-field. These osmium(v) complexes are potentially useful building-blocks for the construction of molecule-based architectures with interesting magnetic properties. In contrast, the structurally related (PPh4)[OsIII(L)(CN)3(NH3)] ([PPh4]3), which also has a low-spin S = 1/2 ground state but with a different electronic configuration (5d5), does not exhibit slow magnetic relaxation, due to the absence of any orbital moment (L = 0). Furthermore, the structurally different osmium(v) hydrazido compound reported by Meyer, [OsV(tpy)(Cl)2(NNC5H10)](PF6) (4[PF6]), also does not exhibit slow magnetic relaxation due possibly to a change in magnetic anisotropy from axial for [PPh4]1 and [PPh4]2 to planar.
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Affiliation(s)
- Qian-Qian Su
- College of Chemistry and Environmental Engineering, Yangtze University, Jingzhou 434020, Hubei, P. R. China.
| | - Kun Fan
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China.
| | - Xin-Da Huang
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China.
| | - Jing Xiang
- College of Chemistry and Environmental Engineering, Yangtze University, Jingzhou 434020, Hubei, P. R. China.
| | - Shun-Cheung Cheng
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong.
| | - Chi-Chiu Ko
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong.
| | - Li-Min Zheng
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China.
| | - Mohamedally Kurmoo
- Institut de Chimie, Université de Strasbourg, CNRS-UMR7177, 4 rue Blaise Pascal, Strasbourg Cedex 67007, France
| | - Tai-Chu Lau
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong.
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Collery P, Desmaele D, Vijaykumar V. Design of Rhenium Compounds in Targeted Anticancer Therapeutics. Curr Pharm Des 2019; 25:3306-3322. [DOI: 10.2174/1381612825666190902161400] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Accepted: 08/30/2019] [Indexed: 12/25/2022]
Abstract
Background:
Many rhenium (Re) complexes with potential anticancer properties have been synthesized
in the recent years with the aim to overcome the clinical limitations of platinum agents. Re(I) tricarbonyl
complexes are the most common but Re compounds with higher oxidation states have also been investigated, as
well as hetero-metallic complexes and Re-loaded self-assembling devices. Many of these compounds display
promising cytotoxic and phototoxic properties against malignant cells but all Re compounds are still at the stage
of preclinical studies.
Methods:
The present review focused on the rhenium based cancer drugs that were in preclinical and clinical
trials were examined critically. The detailed targeted interactions and experimental evidences of Re compounds
reported by the patentable and non-patentable research findings used to write this review.
Results:
In the present review, we described the most recent and promising rhenium compounds focusing on their
potential mechanism of action including, phototoxicity, DNA binding, mitochondrial effects, oxidative stress
regulation or enzyme inhibition. Many ligands have been described that modulating the lipophilicity, the luminescent
properties, the cellular uptake, the biodistribution, and the cytotoxicity, the pharmacological and toxicological
profile.
Conclusion:
Re-based anticancer drugs can also be used in targeted therapies by coupling to a variety of biologically
relevant targeting molecules. On the other hand, combination with conventional cytotoxic molecules, such
as doxorubicin, allowed to take into profit the targeting properties of Re for example toward mitochondria.
Through the example of the diseleno-Re complex, we showed that the main target could be the oxidative status,
with a down-stream regulation of signaling pathways, and further on selective cell death of cancer cells versus
normal cells.
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Affiliation(s)
- Philippe Collery
- Society for the Coordination of Therapeutic Researches, 20220 Algajola, France
| | - Didier Desmaele
- Institut Galien, Universite Paris-Saclay, 92296 Chatenay-Malabry, France
| | - Veena Vijaykumar
- Biotechnology Department, REVA University, Bangalore, 560064, India
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