{"title":"Exploring acidity-dependent PCET pathways in imino-bipyridyl cobalt complexes†","authors":"Jueun Lee, Daeun Jung and Junhyeok Seo","doi":"10.1039/D4DT03221G","DOIUrl":null,"url":null,"abstract":"<p >The electrochemical proton reactivity of transition metal complexes has received intensive attention in catalyst research. The proton-coupled electron transfer (PCET) process, influenced by the coordination geometry, determines the catalytic reaction mechanisms. Additionally, the p<em>K</em><small><sub>a</sub></small> value of a proton source, as an external factor, plays a crucial role in regulating the proton transfer step. Understanding the effects of variations in the p<em>K</em><small><sub>a</sub></small> values of Brønsted acids on the PCET process is therefore essential. This study compares the PCET pathways of two high-spin cobalt (Co) complexes with contrasting exchange coupling interactions under acidic conditions with high and low p<em>K</em><small><sub>a</sub></small> values. These findings reveal how proton reduction reactions in high-spin Co complexes are affected by the internal factor of the spin state, as well as an external factor related to the proton source. The corresponding reaction mechanisms are also proposed based on these observations.</p>","PeriodicalId":71,"journal":{"name":"Dalton Transactions","volume":" 7","pages":" 2776-2782"},"PeriodicalIF":3.5000,"publicationDate":"2025-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Dalton Transactions","FirstCategoryId":"92","ListUrlMain":"https://pubs.rsc.org/en/content/articlelanding/2025/dt/d4dt03221g","RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"CHEMISTRY, INORGANIC & NUCLEAR","Score":null,"Total":0}
引用次数: 0
Abstract
The electrochemical proton reactivity of transition metal complexes has received intensive attention in catalyst research. The proton-coupled electron transfer (PCET) process, influenced by the coordination geometry, determines the catalytic reaction mechanisms. Additionally, the pKa value of a proton source, as an external factor, plays a crucial role in regulating the proton transfer step. Understanding the effects of variations in the pKa values of Brønsted acids on the PCET process is therefore essential. This study compares the PCET pathways of two high-spin cobalt (Co) complexes with contrasting exchange coupling interactions under acidic conditions with high and low pKa values. These findings reveal how proton reduction reactions in high-spin Co complexes are affected by the internal factor of the spin state, as well as an external factor related to the proton source. The corresponding reaction mechanisms are also proposed based on these observations.
期刊介绍:
Dalton Transactions is a journal for all areas of inorganic chemistry, which encompasses the organometallic, bioinorganic and materials chemistry of the elements, with applications including synthesis, catalysis, energy conversion/storage, electrical devices and medicine. Dalton Transactions welcomes high-quality, original submissions in all of these areas and more, where the advancement of knowledge in inorganic chemistry is significant.