[Co5Tp*4(Me2bta)6]: A Highly Symmetrical Pentanuclear Kuratowski Complex Featuring Tris(pyrazolyl)borate and Benzotriazolate Ligands

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• 作者：Tamas W. Werner ; Stephan Reschke ; Hana Bunzen ; Hans-Albrecht Krug von Nidda ; Joachim Deisenhofer ; Alois Loidl ; Dirk Volkmer
• 刊名：Inorganic Chemistry
• 出版年：2016
• 出版时间：February 1, 2016
• 年：2016
• 卷：55
• 期：3
• 页码：1053-1060
• 全文大小：537K
• ISSN：1520-510X

文摘

The pentanuclear Co(II) complex [Co₅Tp*₄(Me₂bta)₆] containing N-donor ligands (5,6-dimethyl benzotriazolate; Me₂bta₆) and N-donor capping ligands (tris(3,5-dimethyl-1-pyrazolyl)borate; Tp*) was prepared by a simple and efficient ligand exchange reaction from [Co₅Cl₄(Me₂bta)₆] and tetra-n-butyl ammonium tris(3,5-dimethyl-1-pyrazolyl)borate. Compared to the precursor complex [Co₅Cl₄(Me₂bta)₆], which contains one Co(II) ion in octahedral and four Co(II) ions in tetrahedral coordination geometry, the title compound features all five Co(II) ions in an octahedral coordination environment while keeping a high complex symmetry. This results in modified properties including improved solubility and distinct magnetic behavior as compared to the precursor complex. The molecular structure and phase purity of the compound was verified by XRPD, UV–vis, ESI-MS, IR, and NMR measurements. Thermal stability of the compound was determined via TGA. The magnetic properties of here reported novel complex [Co₅Tp*₄(Me₂bta)₆] as well as its precursor [Co₅Cl₄(Me₂bta)₆] were examined in detail via ESR and SQUID measurements, which indicated weak anti-ferromagnetic exchange interactions between high-spin Co(II) centers at T < 20 and 50 K, respectively.