大环化合物对钴-脱氢咕啉配合物光化学和电化学性质的影响：Co(I)物种的形成和研究,Inorganic Chemistry

当前位置： X-MOL 学术 › Inorg. Chem. › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

大环化合物对钴-脱氢咕啉配合物光化学和电化学性质的影响：Co(I)物种的形成和研究
Inorganic Chemistry ( IF 4.3 ) Pub Date : 2023-06-12 , DOI: 10.1021/acs.inorgchem.3c00882
Keita Shichijo ₁ , Yohei Kametani ₂ , Yoshihito Shiota ₂ , Kazunari Yoshizawa ₂ , Mamoru Fujitsuka ₃ , Hisashi Shimakoshi ₁

Affiliation

Co(II)-pyrocobester ( P ^-Co(II) ) 是一种脱氢咕啉络合物，由维生素 B ₁₂（氰钴胺）半合成，研究了其光化学和电化学性质，并与 cobester ( C ^{-Co(II)进行了比较。 )} )，钴-咕啉络合物。P ^-Co(II)在 CH ₂ Cl ₂中的紫外可见吸收归因于 π-π* 跃迁，与C ^-Co(II)相比，由于大环的 π 膨胀，其紫外可见吸收发生红移在焦烧中。_{在 CH 3} CN 中，在E _1/2 = -0.30 V vs Ag/AgCl下观察到P ^-Co(II)的可逆氧化还原对，通过 UV- 将其分配给 Co(II)/Co(I) 氧化还原对。 vis、ESR 和分子轨道分析。与C ^-Co(II)相比，该氧化还原对正移了 0.28 V。这是由脱氢咕啉大环的高电负性引起的，这是通过游离碱配体的 DFT 计算估计的。Co(I)-pyrocobester ( P ^-Co(I) ) 的反应性通过在 CV 和 UV-vis 中与碘甲烷反应形成光敏 Co(III)-CH ₃络合物 ( P ^{-Co(III) )-CH3} )。还通过飞秒瞬态吸收（TA）光谱研究了P ^-Co(I)、*Co(I)激发态的性质。根据 587 nm 处的动力学轨迹，*Co(I) 的寿命估计为 29 ps。当存在Ar-X（例如碘苯甲腈（1a）、溴苯甲腈（1b）和氯苯甲腈（1c））时，*Co(I)的寿命变短，并且*Co之间的电子转移（ET）速率常数(I) 和 Ar-X 被确定为 2.9 × 10 ¹¹ M ^–1 s ^–1、 4.9 × 10 ¹⁰ M ^–1 s ^–1和1a、1b和 1.0 × 10 ¹⁰ M ^–1 s ^–1。分别为1c。

"点击查看英文标题和摘要"

Effect of Macrocycles on the Photochemical and Electrochemical Properties of Cobalt-Dehydrocorrin Complex: Formation and Investigation of Co(I) Species

Co(II)-pyrocobester (P^-Co(II)), a dehydrocorrin complex, was semisynthesized from vitamin B₁₂ (cyanocobalamin), and its photochemical and electrochemical properties were investigated and compared to those of the cobester (C^-Co(II)), the cobalt-corrin complex. The UV–vis absorptions of P^-Co(II) in CH₂Cl₂, ascribed to the π–π* transition, were red-shifted compared to those of C^-Co(II) due to the π-expansion of the macrocycle in the pyrocobester. The reversible redox couple of P^-Co(II) was observed at E_1/2 = −0.30 V vs Ag/AgCl in CH₃CN, which was assigned to the Co(II)/Co(I) redox couple by UV–vis, ESR, and molecular orbital analysis. This redox couple was positively shifted by 0.28 V compared to that of C^-Co(II). This is caused by the high electronegativity of the dehydrocorrin macrocycle, which was estimated by DFT calculations for the free-base ligands. The reactivity of the Co(I)-pyrocobester (P^-Co(I)) was evaluated by the reaction with methyl iodide in CV and UV–vis to form a photosensitive Co(III)-CH₃ complex (P^-Co(III)-CH3). The properties of the excited state of P^-Co(I), *Co(I), were also investigated by femtosecond transient absorption (TA) spectroscopy. The lifetime of *Co(I) was estimated to be 29 ps from the kinetic trace at 587 nm. The lifetime of *Co(I) became shorter in the presence of Ar-X, such as iodobenzonitrile (1a), bromobenzonitrile (1b), and chlorobenzonitrile (1c), and the rate constants of electron transfer (ET) between the *Co(I) and Ar-X were determined to be 2.9 × 10¹¹ M^–1 s^–1, 4.9 × 10¹⁰ M^–1 s^–1, and 1.0 × 10¹⁰ M^–1 s^–1 for 1a, 1b, and 1c, respectively.

更新日期：2023-06-12

点击分享查看原文

点击收藏

阅读更多本刊新发论文本刊介绍/投稿指南