权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Synthesis of chromium, manganese, and iron porphyrin complexes with less common electron configuration.

具有不太常见电子构型的铬、锰和铁卟啉配合物的合成。

基本信息

批准号：
10640551
负责人：
NAKAMURA Mikio
金额：
$ 1.92万
依托单位：
TOHO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 2000
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10640551/
关键词：
porphyrins iron complexes manganese complexes NMR spectroscopy electron configuration low spin complexes solvent effect hydrogen bonding NMRスペクトル NMR ポルフィリン鉄錯体ポルフィリン-マンガン錯体スピン状態

项目摘要

The electron configuration of low spin iron (III) porphyrin complexes is generally represented as (d_<xy>)^2(d_<xz>, d_<yz>)^3(d_π type). Recently, We have found that the energy levels of the iron d_<xy> and d_π(d_<xz>, d_<yz>) orbitals are reversed in some complexes with highly nonplanar porphyrin rings, resulting in the formation of the less common (d_<xz>, d_<yz>)^4(d_<xy>)^1(d_<xy> type) ground state. We started the project three years ago to reveal the factors that affect the electronic ground state of low spin iron (III), manganese (III), and chromium (III) porphyrin complexes.Three factors that could affect the electron configuration of low spin iron (III) are, i) coordination ability of axial ligands, ii) deformation mode of porphyrin ring, and iii) electronic effect of the peripheral substituents. By the extensive studies using ^1H NMR, ^<13>C NMR, and EPR spectra, we have found that i) strong axial ligands such as imidazole and dimethylaminopyridine stabilize the d_π type, while weak axial ligands such as tert-butylisocyanide and 4-cyanopiridine stabilize the d_<xy> type, ii) highly saddle shaped porphyrin rings such as octaethyltetraphenyl-porphyrin stabilize the d_π type, while highly ruffled porphyrin rings such as meso-tetraisopropylporphyrin stabilize the d_<xy> type, iii) porphyrins carrying electron withdrawing substituents at the meso positions stabilize the d_π type, while those with electron donating groups prefer the d_<xy> type.We have then examined the effect of porphyrin deformation on the electron configuration of manganese (III) porphyrin complexes. However, even by the addition of excess cyanide, the expected bis-adduct was not a sole product. Instead, the mixture of the mono and bis-addcut was observed. Close examination of the coordination reaction has revealed that the ratio, mono vs. bis, chages depending upon the nature of the solvents used. The study to reveal this interesting phenomenon is now in progress.

低自旋铁卟啉配合物的电子构型一般表示为（d_<xy>）^2（d_<xz>，d_<yz>）^3（d_π型）。最近，我们发现在某些具有高度非平面卟啉环的配合物中，铁的d_<xy>和d_π（d_<xz>，d_<yz>）轨道的能级发生了反转，从而形成了不常见的（d_<xz>，d_<yz>）^4（d_<xy>）^1（d_<xy>type）基态。我们从三年前开始研究影响低自旋铁（III）、锰（III）和铬（III）卟啉配合物基态电子构型的因素，发现影响低自旋铁（III）卟啉配合物基态电子构型的三个因素是：轴向配体的配位能力、卟啉环的形变方式和外围取代基的电子效应。通过~ 1H NMR、~ 1C <13>NMR和EPR谱的研究发现，强轴向配体如咪唑和二甲氨基吡啶稳定d_π型，弱轴向配体如叔丁基异氰和4-氰基吡啶稳定d_π型<xy>，高度鞍形的卟啉环如八乙基四苯基卟啉稳定d_π型，高度皱边的卟啉环如meso-四异丙基卟啉稳定d_π型<xy>，在meso位置上带有吸电子取代基的卟啉稳定d_π型，而带有供电子基团的卟啉则倾向于d_<xy>型，我们研究了卟啉形变对锰（III）卟啉配合物电子构型的影响。然而，即使通过加入过量的氰化物，预期的双加合物也不是唯一的产物。相反，观察到单和双加成产物的混合物。对配位反应的仔细研究表明，单与双的比例取决于所用溶剂的性质。揭示这一有趣现象的研究正在进行中。