Steric effect on construction of Cu(II) complexes with pyridine carboxamide ligands

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• 作者：Do Nam Lee ; Ji Young Ryu ; Han Kwak ; Young Min Lee ; Sun Hwa Lee ; Jung In Poong ; Junghyun Lee ; Woonsup Shin ; Cheal Kim ; Sung-Jin Kim ; Youngmee Kim
• 关键词：Pyridine carboxamide ; Copper(II) complex ; Crystal structure ; Steric effect
• 刊名：Journal of Molecular Structure
• 出版年：2008
• 出版时间：14 August 2008
• 年：2008
• 卷：885
• 期：1-3
• 页码：56-63
• 全文大小：897 K

文摘

The structures of three new Cu(II) complexes with pyridine carboxamide ligands (Me₂bpb, 6-Me₂-Mebpb, and 6-Me₂-Me₂bpb) have been determined. 6-Methyl-substituted pyridyl bpb ligands produced dimeric compounds with Cu(II) ions, and weak interactions between dimers can make even polymeric compounds, while bpb ligands without 6-methyl substitution produced monomeric Cu(II) complexes. The large distortion effects of 6-methyl-substitution are shown in Cu(II) complexes with 6-methyl-substituted pyridyl bpb ligands. This result suggests that the steric effect of 6-methyl-substitution plays important role for distortion of the structure, and 6-methyl-substitution can also influence to make polymeric compounds with interactions between Cu(II) ions and neighbor carbonyl oxygen atoms. In addition, the voltammetric behaviors of the Cu complexes were examined and classified into two groups, with/without 6-methyl group. The complexes without 6-methyl group show reversible redox waves at −1.6 V, and the complexes with 6-methyl group do irreversible redox ones at −1.3 V, indicating that the presence of the methyl group of 6-position of the complex makes the reduction of the complexes easier.