Ghiladi Reza A, Rheingold Arnold L, Siegler Maxime A, Karlin Kenneth D
Department of Chemistry, The Johns Hopkins University, Baltimore, Maryland 21218, USA.
Inorganica Chim Acta. 2012 Jul 1;389:131-137. doi: 10.1016/j.ica.2012.02.020. Epub 2012 Feb 23.
This report describes our approach towards modelling the copper cluster active sites of nitrous oxide reductase and the multicopper oxidases/oxygenases. We have synthesized two mesitylene-based trinucleating ligands, MesPY1 and MesPY2, which employ bis(2-picolyl)amine (PY1) and bis(2-pyridylethyl)amine (PY2) tridentate copper chelates, respectively. Addition of cuprous salts to these ligands leads to the isolation of tricopper(I) complexes (Mes-PY1)Cu(I) (3)(CH(3)CN)(3)(3)·0.25Et(2)O (1) and (Mes-PY2)Cu(I) (3)(3) (3) Each of the three copper centers in 1 is most likely four-coordinate, with ligated acetonitrile as the fourth ligand; by contrast, the copper centers in 3 are three-coordinate, as determined by X-ray crystallography The synthesis of (Mes-PY1)Cu(II) (3)(CH(3)CN)(2)(CH(3)OH)(2)(6)·(CH(3)OH) (2) was accomplished by addition of three equivalents of the copper(II) salt, Cu(ClO(4))(2)·6H(2)O, to the ligand. The structure of 2 shows that two of the copper centers are tetracoordinate (with MeCN solvent ligation), but have additional weak axial (fifth ligand) interactions with the perchlorate anions; the third copper is unique in that it is coordinated by two MeOH solvent molecules, making it overall five-coordinate. For complexes 2 and 3, one copper ion center is located on the opposite side of the mesitylene plane as the other two. These observations, although in the solid state, must be taken into account for future studies where intramolecular tricopper(I)/O(2) (or other small molecules of interest) interactions in solution are desirable.
本报告描述了我们对一氧化二氮还原酶以及多铜氧化酶/加氧酶的铜簇活性位点进行建模的方法。我们合成了两种基于均三甲苯的三核配体，即MesPY1和MesPY2，它们分别采用双（2 - 吡啶甲基）胺（PY1）和双（2 - 吡啶乙基）胺（PY2）三齿铜螯合物。向这些配体中加入亚铜盐会分离出三铜（I）配合物[（Mes - PY1）Cu（I）₃（CH₃CN）₃]（ClO₄）₃·0.25Et₂O（1）和[（Mes - PY2）Cu（I）₃]（PF₆）₃（3）。1中的三个铜中心每个很可能是四配位的，以配位的乙腈作为第四个配体；相比之下，通过X射线晶体学确定，3中的铜中心是三配位的。通过向配体中加入三当量的铜（II）盐Cu（ClO₄）₂·6H₂O，合成了[（Mes - PY1）Cu（II）₃（CH₃CN）₂（CH₃OH）₂]（ClO₄）₆·（CH₃OH）₂（2）。2的结构表明，其中两个铜中心是四配位的（有乙腈溶剂配位），但与高氯酸根阴离子有额外的弱轴向（第五个配体）相互作用；第三个铜的独特之处在于它由两个甲醇溶剂分子配位，使其总体上为五配位。对于配合物2和3，一个铜离子中心位于均三甲苯平面的与另外两个相对的一侧。尽管这些观察结果是在固态下得到的，但在未来希望研究溶液中分子内三铜（I）/O₂（或其他感兴趣的小分子）相互作用的研究中必须予以考虑。
