Synthesis and Characterization of Tetrahedral and Square Planar Bis(iminopyrrolyl) Complexes of Cobalt(II)

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• 作者：Só ; nia A. Carabineiro ; Leonel C. Silva ; Pedro T. Gomes ; Laura C. J. Pereira ; Luí ; s F. Veiros ; Sofia I. Pascu ; M. Teresa Duarte ; Só ; nia Namorado ; Rui T. Henriques
• 刊名：Inorganic Chemistry
• 出版年：2007
• 出版时间：August 20, 2007
• 年：2007
• 卷：46
• 期：17
• 页码：6880 - 6890
• 全文大小：293K
• 年卷期：v.46,no.17(August 20, 2007)
• ISSN：1520-510X

文摘

A series of 2-iminopyrrole ligand precursors with increasing bulkiness [HNC₄H₃C(R)=N-2,6-R'₂C₆H₃] (R = R' =H, 1a; R = Me, R'= H, 1b; R = H, R' = Me, 1c; R = R' = Me, 1d; R = H, R' = ⁱPr, 1e; R = Me, R' = ⁱPr,1f) were synthesized and deprotonated with NaH to give the corresponding iminopyrrolyl sodium salts 2a-f. A setof homoleptic bis-ligand Co(II) complexes of the type [Co(²N,N'-NC₄H₃C(R)=N-2,6-R'₂C₆H₃)₂] (R = R'= H, 3a;R = Me, R'= H, 3b; R = H, R' = Me, 3c; R = R' = Me, 3d; R = H, R' = ⁱPr, 3e; R = Me, R' = ⁱPr, 3f) wasprepared by reaction of CoCl₂ with the corresponding iminopyrrolyl sodium salts 2a-f. The new complexes werecharacterized by elemental analysis, magnetic susceptibility measurements, in powder and in solution, UV/vis/NIR,and, in some cases, X-ray crystallography. According to X-ray diffraction and magnetic measurements, the Cocomplexes 3a-e proved to be tetrahedral, which is the preferred geometry for Co(II) compounds. However, asquare planar geometry is observed in the case of 3f, as determined by several characterization techniques. In thiscase, DFT calculations suggest the square planar geometry is slightly more stable than the tetrahedral one probablydue to a combination of steric and electronic reasons.