Diquinol Functionality Boosts the Superoxide Dismutase Mimicry of a Zn(II) Complex with a Redox-Active Ligand while Maintaining Catalyst Stability and Enhanced Activity in Phosphate Solution
Diquinol Functionality Boosts the Superoxide Dismutase Mimicry of a Zn(II) Complex with a Redox-Active Ligand while Maintaining Catalyst Stability and Enhanced Activity in Phosphate Solution
复制标题
二喹啉功能可增强具有氧化还原活性配体的 Zn(II) 络合物的超氧化物歧化酶模拟，同时保持催化剂稳定性并增强磷酸盐溶液中的活性
DOI：
10.1021/acs.inorgchem.2c03256
复制
发表时间：
2022
影响因子：
4.6
通讯作者：
Schwartz, Dean D.
中科院分区：
文献类型：
--
作者：
Moore, Jamonica L.;Oppelt, Julian;Senft, Laura;Franke, Alicja;Scheitler, Andreas;Dukes, Meghan W.;Alix, Haley B.;Saunders, Alexander C.;Karbalaei, Sana;Schwartz, Dean D.
在目前的工作中，我们展示了配体设计的概念，显着提高超氧化物歧化酶（SOD）活性的锌络合物，催化增强时，两个醌醇基团存在于多齿配体。我们调查的机制，通过该醌醇影响的催化和确定的影响，完全去除螯合基团从原来的六齿配体。我们的研究结果表明，这些化合物的SOD模拟需要一个配体，协调锌（II）强烈在其氧化和还原形式，并通过锌（II）-semiquinone配合物的活动进行。与两个喹啉的配合物显示出大大增强的催化能力，与一个单一的喹啉的相关配合物的活性提高高达450%。在二醌醇络合物的还原形式中，一种醌醇似乎比另一种更弱地与锌配位。我们认为，超氧化物可以更容易地取代这部分的配体，促进其协调的金属中心，从而加快SOD的反应。尽管存在两个氧化还原活性基团，可以通过分子内氢键和氧化还原互变异构进行通信，只有一个醌在催化过程中经历两个电子氧化对醌。对苯醌形成后，剩余的醌醇去质子化并与金属紧密结合，确保复合物在氧化状态下保持完整，从而保持其催化能力。锌（II）配合物与二醌醇配体是非常不寻常的SOD模拟，因为它在磷酸盐溶液中更有效地执行。
In the current work, we demonstrate ligand design concepts that significantly improve the superoxide dismutase (SOD) activity of a zinc complex; the catalysis is enhanced when two quinol groups are present in the polydentate ligand. We investigate the mechanism through which the quinols influence the catalysis and determine the impact of entirely removing a chelating group from the original hexadentate ligand. Our results suggest that SOD mimicry with these compounds requires a ligand that coordinates Zn(II) strongly in both its oxidized and reduced forms and that the activity proceeds through Zn(II)-semiquinone complexes. The complex with two quinols displays greatly enhanced catalytic ability, with the activity improving by as much as 450% over a related complex with a single quinol. In the reduced form of the diquinol complex, one quinol appears to coordinate to the zinc much more weakly than the other. We believe that superoxide can more readily displace this portion of the ligand, facilitating its coordination to the metal center and thereby hastening the SOD reactivity. Despite the presence of two redox-active groups that may communicate through intramolecular hydrogen bonding and redox tautomerism, only one quinol undergoes two-electron oxidation to apara-quinone during the catalysis. After the formation of thepara-quinone, the remaining quinol deprotonates and binds tightly to the metal, ensuring that the complex remains intact in its oxidized state, thereby maintaining its catalytic ability. The Zn(II) complex with the diquinol ligand is highly unusual for a SOD mimic in that it performs more efficiently in phosphate solution.