Functional Myoglobin Model Composed of a Strapped Porphyrin/Cyclodextrin Supramolecular Complex with an Overhanging COOH That Increases O<sub>2</sub>/CO Binding Selectivity in Aqueous Solution
Functional Myoglobin Model Composed of a Strapped Porphyrin/Cyclodextrin Supramolecular Complex with an Overhanging COOH That Increases O<sub>2</sub>/CO Binding Selectivity in Aqueous Solution
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由带悬垂 COOH 的带状卟啉/环糊精超分子复合物组成的功能性肌红蛋白模型，可提高水溶液中 O<sub>2</sub>/CO 的结合选择性
DOI：
10.1021/acs.inorgchem.1c01628
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发表时间：
2021
影响因子：
4.6
通讯作者：
Kitagishi Hiroaki
中科院分区：
文献类型：
--
作者：
Mao Qiyue;Das Pradip K.;Le Gac St?phane;Boitrel Bernard;Dorcet Vincent;Oohora Koji;Hayashi Takashi;Kitagishi Hiroaki
为了模拟肌红蛋白的功能，合成了一种侧链上带有两个丙基吡啶和一个羧基的水溶性四芳基铁卟啉（FeIIIPor-1），它与带有吡啶连接基的全O-甲基化β-环糊精二聚体（Py 3 OCD）形成1：1的稳定包合物，提供疏水环境和近端第五配体来稳定O2-络合物.铁配合物（FeIIPorCD-1）在水溶液中同时结合O2和CO。在pH 7和25 °C下，FeIIP或CD-1的O2和CO结合亲和力（P1/2 O2和P1/2CO）和O2络合物的半衰期（t1/2）分别为6.3和0.021 Torr和7 h。不具有带状结构的对照化合物（FeIIPorCD-2）具有类似的氧结合特性（P1/2 O2 = 8.0 Torr），但具有更高的CO结合亲和力（P1/2CO= 3.8 × 10- 4 Torr）和更长的1/2（30 h）。O2和CO动力学表明，FeIIPorCD-1的束缚结构抑制了这些气态配体进入铁（II）中心，较低的konO 2和konCO值证明了这一点。有趣的是，FeIIP或CD-1的CO络合物明显不稳定（相对较大的koffCO），而koffO 2值比FeIIP或CD-2的小得多，导致FeIIP或CD-1中的O2/CO选择性（降低的M值，其中M =P1/2 O2/P1/2CO= 320）与FeIIP或CD-2（M= 21000）相比显著增加。
A water-soluble strapped iron(III)tetraarylporphyrin (FeIIIPor-1) bearing two propylpyridinium groups at the side chains and a carboxylic acid group at the overhanging position of the strap was synthesized to mimic the function of myoglobin with the distal polar functionality in aqueous solution.FeIIIPor-1forms a stable 1:1 inclusion complex with a per-O-methylated β-cyclodextrin dimer having a pyridine linker (Py3OCD), providing a hydrophobic environment and a proximal fifth ligand to stabilize the O2-complex. The ferrous complex (FeIIPorCD-1) binds both O2and CO in aqueous solution. The O2and CO binding affinities (P1/2O2andP1/2CO) and half-life time (t1/2) of the O2complex ofFeIIPorCD-1are 6.3 and 0.021 Torr, and 7 h, respectively, at pH 7 and 25 °C. The control compound without the strap structure (FeIIPorCD-2) has similar oxygen binding characteristics (P1/2O2= 8.0 Torr), but much higher CO binding affinity (P1/2CO= 3.8 × 10–4Torr), and longert1/2(30 h). The O2and CO kinetics indicate that the strapped structure inFeIIPorCD-1inhibits the entrance of these gaseous ligands into the iron(II) center, as evidenced by lowerkonO2andkonCOvalues. Interestingly, the CO complex ofFeIIPorCD-1is significantly destabilized (relatively largerkoffCO), while thekoffO2value is much smaller than that ofFeIIPorCD-2, resulting in significantly increased O2/CO selectivity (reducedMvalue, whereM=P1/2O2/P1/2CO= 320) inFeIIPorCD-1compared toFeIIPorCD-2(M= 21000).