Unprecedented copper(ii)-assisted acetal formation of a formyl-substituted bispyrazole. The X-ray structures of copper[1,2-bis(3′-dimethoxymethylpyrazol-1′-yl)ethane] dichloride and dibromide
作者:Iryna A. Koval、Anna M. Schuitema、Willem L. Driessen、Jan Reedijk
DOI:10.1039/b104655c
日期:2001.12.13
The formation of two new acetal-containing ligands 1,2-bis(3â²-dimethoxymethylpyrazol-1â²-yl)ethane (bdmpe) and 1,2-bis(3â²-diethoxymethylpyrazol-1â²-yl)ethane (bdepe) in a Cu(II)-assisted alcoholysis of the initial ligand 1,2-bis(3â²-formylpyrazol-1â²-yl)ethane is described. The new ligands form polymeric complexes with Cu(II) salts of the general formula [Cu(L)X2]x, where L = bdmpe or bdepe, and X = Cl or Br. The single-crystal X-ray structures of [Cu(bdmpe)Cl2]x and [Cu(bdmpe)Br2]x show that two of the four oxygen atoms of the acetal fragments are axially semi-coordinated to the copper(II) ions, adjusting the coordination sphere around the metal ion to a very distorted octahedron. The coordination of the oxygen atoms of the acetal groups to the metal ion may well be the driving force for the transformation
of the initial aldehyde groups into the acetal fragments. The equatorial plane in [Cu(bdmpe)Cl2]x is a trans-CuN2Cl2 chromophore, while in [Cu(bdmpe)Br2]x it is a cis-CuN2Br2 species with a large in-plane distortion.
本文描述了在 Cu(II)-assisted alcoholysis of the initial ligand 1,2-bis(3â²-formylpyrazol-1â²-yl)ethane (bdmpe) 和 1,2-bis(3â²-diethoxymethylpyrazol-1â²-yl)ethane (bdepe) 的过程中,两种新的含缩醛配体 1,2-bis(3â²-formylpyrazol-1â²-yl)ethane (bdmpe) 的形成。新配体与铜(II)盐形成通式为[Cu(L)X2]x的聚合物配合物,其中 L = bdmpe 或 bdepe,X = Cl 或 Br。[Cu(bdmpe)Cl2]x和[Cu(bdmpe)Br2]x的单晶X射线结构显示,缩醛片段的四个氧原子中有两个与铜(II)离子呈轴向半配位,从而将金属离子周围的配位球调整为一个非常扭曲的八面体。缩醛基团的氧原子与金属离子的配位很可能是最初的醛基团转化为缩醛片段的驱动力。Cu(bdmpe)Cl2]x 中的赤道面是反式-CuN2Cl2 发色团,而 [Cu(bdmpe)Br2]x 中的赤道面是顺式-CuN2Br2 物种,具有较大的面内畸变。