Nayanika Kalita, Matthew R Crawley, Lauren E Rosch, Owen Szeglowski, Timothy R Cook
{"title":"Exploring the Te(II)/Te(IV) Redox Couple of a Tellurorosamine Chromophore: Photophysical, Photochemical, and Electrochemical Studies.","authors":"Nayanika Kalita, Matthew R Crawley, Lauren E Rosch, Owen Szeglowski, Timothy R Cook","doi":"10.1021/acs.inorgchem.4c01077","DOIUrl":null,"url":null,"abstract":"<p><p>A tellurorosamine dye [<b>Te(II)</b>] undergoes aerobic photooxidation. Although Te(IV) species have been used in a number of oxidations, key Te(IV)-oxo and Te(IV)-bis(hydroxy) intermediates are challenging to study. Under aerobic irradiation with visible light, <b>Te(II)</b> (λ<sub>max</sub> = 600 nm) transforms into a Te(IV) species (λ<sub>max</sub> = 669 nm). The resultant Te(IV) species is not stable in the dark or at -20 °C, decomposing back to <b>Te(II)</b> and other byproducts over many hours. To eliminate the structural ambiguity of the Te(IV) photoproduct, we used spectroelectrochemistry, wherein the bis(hydroxy) <b>Te(IV)-(OH)<sub>2</sub></b> was electrochemically generated under anaerobic conditions. The absorption of <b>Te(IV)-(OH)<sub>2</sub></b> matches that of the Te(IV) photoproduct. Because isosbestic points are maintained both photochemically and electrochemically, the oxo core formed photochemically must rapidly equilibrate with <b>Te(IV)-(OH)<sub>2</sub></b>. Calculations on the bis(hydroxy) versus oxo species further corroborate that the equilibration is rapid and the spectra of the two species are similar. To further explore Te(IV) cores, two novel compounds, <b>Te(IV)-Cl<sub>2</sub></b> and <b>Te(IV)-Br<sub>2</sub></b>, were synthesized. Characterization of <b>Te(IV)-X<sub>2</sub></b> was simplified because these cores have no analogue to the <b>Te(IV)-(O)/Te(IV)-(OH)<sub>2</sub></b> equilibrium. This work provides insights into the photophysical and electrochemical behavior of Te analogues of chalcogenoxanthylium dyes, which are relevant for a broad range of photochemical applications.</p>","PeriodicalId":40,"journal":{"name":"Inorganic Chemistry","volume":null,"pages":null},"PeriodicalIF":4.3000,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Inorganic Chemistry","FirstCategoryId":"92","ListUrlMain":"https://doi.org/10.1021/acs.inorgchem.4c01077","RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"2024/7/11 0:00:00","PubModel":"Epub","JCR":"Q1","JCRName":"CHEMISTRY, INORGANIC & NUCLEAR","Score":null,"Total":0}
引用次数: 0
Abstract
A tellurorosamine dye [Te(II)] undergoes aerobic photooxidation. Although Te(IV) species have been used in a number of oxidations, key Te(IV)-oxo and Te(IV)-bis(hydroxy) intermediates are challenging to study. Under aerobic irradiation with visible light, Te(II) (λmax = 600 nm) transforms into a Te(IV) species (λmax = 669 nm). The resultant Te(IV) species is not stable in the dark or at -20 °C, decomposing back to Te(II) and other byproducts over many hours. To eliminate the structural ambiguity of the Te(IV) photoproduct, we used spectroelectrochemistry, wherein the bis(hydroxy) Te(IV)-(OH)2 was electrochemically generated under anaerobic conditions. The absorption of Te(IV)-(OH)2 matches that of the Te(IV) photoproduct. Because isosbestic points are maintained both photochemically and electrochemically, the oxo core formed photochemically must rapidly equilibrate with Te(IV)-(OH)2. Calculations on the bis(hydroxy) versus oxo species further corroborate that the equilibration is rapid and the spectra of the two species are similar. To further explore Te(IV) cores, two novel compounds, Te(IV)-Cl2 and Te(IV)-Br2, were synthesized. Characterization of Te(IV)-X2 was simplified because these cores have no analogue to the Te(IV)-(O)/Te(IV)-(OH)2 equilibrium. This work provides insights into the photophysical and electrochemical behavior of Te analogues of chalcogenoxanthylium dyes, which are relevant for a broad range of photochemical applications.
期刊介绍:
Inorganic Chemistry publishes fundamental studies in all phases of inorganic chemistry. Coverage includes experimental and theoretical reports on quantitative studies of structure and thermodynamics, kinetics, mechanisms of inorganic reactions, bioinorganic chemistry, and relevant aspects of organometallic chemistry, solid-state phenomena, and chemical bonding theory. Emphasis is placed on the synthesis, structure, thermodynamics, reactivity, spectroscopy, and bonding properties of significant new and known compounds.