Functional models for catechol dioxygenases: iron(III) complexes of cis-facially coordinating linear 3N ligands.
Functional models for catechol dioxygenases: iron(III) complexes of cis-facially coordinating linear 3N ligands.
复制标题
儿茶酚双加氧酶的功能模型：顺面配位线性 3N 配体的铁 (III) 复合物。
DOI：
10.1016/j.jinorgbio.2005.01.008
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发表时间：
2005
影响因子：
3.9
通讯作者：
M. Palaniandavar
中科院分区：
文献类型：
--
作者：
M. Velusamy;R. Mayilmurugan;M. Palaniandavar
一系列的1：1铁（III）配合物的简单和空间位阻的三齿3 N供体配体已被合成和研究作为功能模型的儿茶酚双加氧酶。它们均为[FeLCl 3]型，其中L为双（吡啶-2-基甲基）胺（L1）、N，N-双（苯并咪唑-2-基甲基）胺（L2）、N-甲基-N′-（吡啶-2-基甲基）乙二胺（L3）、N，N-二甲基-N′-（吡啶-2-基甲基）乙二胺（L4）和N-苯基-N′-（吡啶-2-基甲基）乙二胺（L5）。它们的特征在于光谱和电化学方法。测定了配合物[Fe（L_4）Cl_3]的X射线晶体结构。该配合物的晶体结构属于三斜晶系空间群P1 '，a=7.250（6），b=8.284（3），c=12.409（4），α=80.84（3）°，β=86.76（6）°，γ=72.09（7）°，Z=2。它具有扭曲的八面体几何形状，其中L4配体与铁（III）顺式配位，氯离子占据其余的配位位点。在配体供体原子类型的系统变化显着影响的刘易斯酸性的铁（III）中心，因此简单的和取代的儿茶酚的配合物的结合相互作用。研究了原位生成的邻苯二酚配合物的光谱和电化学性质。所有配合物主要催化3，5-二叔丁基邻苯二酚（H_2DBC）在分子氧存在下的二醇内氧化裂解，这与配体的顺式面配位是出乎意料的。二醇内邻苯二酚裂解反应的速率取决于铁（III）中心的刘易斯酸性和配体的空间位阻需求和氢键功能。有趣的是，N-苯基取代基在[Fe（L5）Cl 3]配合物中的电子阱性质导致裂解速率的增强。所有这些观察结果提供了支持底物激活机制提出的intradiol裂解酶。
A series of 1:1 iron(III) complexes of simple and sterically hindered tridentate 3N donor ligands have been synthesized and studied as functional models for catechol dioxygenases. All of them are of the type [FeLCl3], where L is bis(pyrid-2-yl-methyl)amine (L1), N,N-bis(benzimidazol-2-ylmethyl)amine (L2), N-methyl-N′-(pyrid-2-ylmethyl)ethylenediamine (L3), N,N-dimethyl-N′-(pyrid-2-ylmethyl)-ethylenediamine (L4) and N-phenyl-N′-(pyrid-2-ylmethyl)ethylenediamine (L5). They have been characterised by spectral and electrochemical methods. The X-ray crystal structure of the complex [Fe(L4)Cl3] has been successfully determined. The complex crystallizes in the triclinic space group P1¯ with a=7.250(6), b=8.284(3), c=12.409(4)Å, α=80.84(3)°, β=86.76(6)°, γ=72.09(7)° and Z=2. It possesses a distorted octahedral geometry in which the L4 ligand is cis-facially coordinated to iron(III) and the chloride ions occupy the remaining coordination sites. The systematic variation in the ligand donor atom type significantly influences the Lewis acidity of the iron(III) center and hence the binding interaction of the complexes with simple and substituted catechols. The spectroscopic and electrochemical properties of the catecholate complexes generated in situ have been investigated. All the complexes catalyze mainly the oxidative intradiol cleavage of 3,5-di-tert-butylcatechol (H2DBC) in the presence of dioxygen, which is unexpected of the cis-facial coordination of the ligands. The rate of intradiol catechol cleavage reaction depends upon the Lewis acidity of iron(III) center and steric demand and hydrogen-bonding functionalities of the ligands. Interestingly, the electron-sink property of N-phenyl substituent in [Fe(L5)Cl3] complex leads to enhancement in rate of cleavage. All these observations provide support to the substrate activation mechanism proposed for intradiol-cleaving enzymes.
影响因子：
5.7
作者：
M. Vetting;D. Ohlendorf
通讯作者：
M. Vetting;D. Ohlendorf
影响因子：
5.6
作者：
OHLENDORF, DH;ORVILLE, AM;LIPSCOMB, JD
通讯作者：
LIPSCOMB, JD