Coordination Chemistry of Amine Bis(phenolate) Cobalt(II), Nickel(II), and Copper(II) Complexes

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• 作者：Laura Rodr&iacute ; guez ; Elena Labisbal ; Antonio Sousa-Pedrares ; José ; Arturo Garc&iacute ; a-Vá ; zquez ; Jaime Romero ; Mar&iacute ; a Luz Durá ; n ; José ; A. Real ; Antonio Sousa
• 刊名：Inorganic Chemistry
• 出版年：2006
• 出版时间：September 18, 2006
• 年：2006
• 卷：45
• 期：19
• 页码：7903 - 7914
• 全文大小：244K
• 年卷期：v.45,no.19(September 18, 2006)
• ISSN：1520-510X

文摘

Cobalt(II), nickel(II), and copper(II) (1, 2, and 3) complexes of the dianionic form of the bis(phenolate) ligandN,N-bis(3,4-dimethyl-2-hydroxybenzyl)-N',N'-dimethylethylenediamine (H₂L) have been synthesized by electrochemicaloxidation of the appropriate metal in an acetonitrile solution of the ligand. When copper is used as the anode, theaddition of 1,10-phenanthroline to the electrolytic phase gave rise to a different compound [CuL]₂·2CH₃CN (4). Thecompounds [CoL]₂·2CH₃CN (1), [Ni₂L₂(H₂O)]·H₂O (2), [CuL]₂·3H₂O (3), and [CuL]₂·2CH₃CN (4) were characterizedby microanalysis, IR, electronic spectroscopy, FAB mass spectrometry, magnetic measurements and by single-crystal X-ray diffraction. The crystal structures show that the complexes have a dinuclear structure. In compounds1, 3, and 4, two metal ions are coordinated by the two amine nitrogens and the two phenol oxygen atoms of adeprotonated pendant phenol ligand, with one phenolic oxygen atom from ligand acting as a bridge. In compounds1 and 3, each metal center has a geometry that is closest to trigonal bipyramidal. Magnetic susceptibility data forboth compounds show an antiferromagnetic coupling with 2J = -15 cm^-1 for the cobalt(II) complex and a strongantiferromagnetic coupling with 2J = -654 cm^-1 for the copper(II) complex. However, in 4 the geometry aroundthe metal is closer to square pyramidal and the compound shows a lower antiferromagnetic coupling (2J = -90cm^-1) than in 3. The nickel atoms in the dimeric compound 2 are hexacoordinate. The NiN₂O₄ chromophore hasa highly distorted octahedral geometry. In this structure, a dianionic ligand binds to one nickel through the twoamine nitrogen atoms and the two oxygen atoms and to an adjacent nickel via one of these oxygen atoms. Thenickel atoms are linked through a triple oxygen bridge involving two phenolic oxygens, each from a different ligand,and an oxygen atom from a water molecule. The two nickel ions in 2 are ferromagnetically coupled with 2J = 19.8cm^-1.