Sprutta Natasza, Rath Sankar Prasad, Olmstead Marilyn M, Balch Alan L
Department of Chemistry, University of California, Davis, California 95616, USA.
Inorg Chem. 2005 Mar 7;44(5):1452-9. doi: 10.1021/ic0486623.
The crystal structures of meso-NH2-OEPH2, NiII(meso-NH2-OEP), and CuII(meso-NH2-OEP) (where OEP is the dianion of meso-amino-octaethylporphyrin) have been determined to examine the effects of the meso-substituent on the geometry of the ligand. CuII(meso-NH2-OEP) has a nearly planar geometry while the free ligand itself and NiII(meso-NH2-OEP) have ruf conformations. NiII(meso-NH2-OEP) is much less reactive toward oxidation than are (py)2FeII(meso-NH2-OEP), ClFeIII(meso-NH2-OEP), or NiII(meso-HO-OEP), which all undergo oxidation in pyridine solution when exposed to dioxygen. Treatment of NiII(meso-NH2-OEP) with iron(III) chloride in chloroform solution does result in oxidation of the ligand in two separate processes. One involves oxygenation at the trans-meso position, while the other results in ring cleavage and removal of the amino function. The open-chain tetrapyrrole complex, NiII(OEB-CO2Et), has been characterized by single-crystal X-ray diffraction and shown to contain a helical ligand with a four-coordinate nickel ion.
已测定了内消旋 - NH₂ - OEPH₂、NiII(内消旋 - NH₂ - OEP)和CuII(内消旋 - NH₂ - OEP)（其中OEP是内消旋 - 氨基 - 八乙基卟啉的二价阴离子）的晶体结构，以研究内消旋取代基对配体几何结构的影响。CuII(内消旋 - NH₂ - OEP)具有近乎平面的几何结构，而游离配体本身和NiII(内消旋 - NH₂ - OEP)具有ruf构象。与(py)₂FeII(内消旋 - NH₂ - OEP)、ClFeIII(内消旋 - NH₂ - OEP)或NiII(内消旋 - HO - OEP)相比，NiII(内消旋 - NH₂ - OEP)对氧化的反应活性要低得多，(py)₂FeII(内消旋 - NH₂ - OEP)、ClFeIII(内消旋 - NH₂ - OEP)和NiII(内消旋 - HO - OEP)在吡啶溶液中暴露于氧气时都会发生氧化。在氯仿溶液中用氯化铁处理NiII(内消旋 - NH₂ - OEP)确实会在两个不同的过程中导致配体氧化。一个过程涉及反式内消旋位置的氧合作用，而另一个过程则导致环裂解并去除氨基官能团。开链四吡咯配合物NiII(OEB - CO₂Et)已通过单晶X射线衍射进行了表征，并显示其含有一个带有四配位镍离子的螺旋配体。
