Taija L. Fischer, Casper V. Jensen, Eaindra Lwin, Dhritabrata Pal, Henrik G. Kjaergaard and Martin A. Suhm
{"title":"一水三甲胺的oh -拉伸动力学:我们可以从三种不同的直接吸收光谱中学到什么?","authors":"Taija L. Fischer, Casper V. Jensen, Eaindra Lwin, Dhritabrata Pal, Henrik G. Kjaergaard and Martin A. Suhm","doi":"10.1039/D5CP01424G","DOIUrl":null,"url":null,"abstract":"<p >The hydrogen-bonded binary complex between water and trimethylamine is characterised in jet expansions, in the room temperature gas phase and in frozen argon matrices <em>via</em> its OH-stretching fundamental. The spectral comparison reveals two bracketing resonance partners with weak environmental dependence of their wavenumber. They correspond to the water bending overtone alone and in combination with a stretching motion of the monomers relative to each other. The environment-sensitive OH-stretching mode moves from the combination band location at room temperature all the way down to the pure water bending overtone in cryomatrix isolation, sharing its infrared intensity in proportion to the spectral vicinity and coupling strength. The intermediate jet-cooled spectrum largely removes thermal excitation and embedding effects. It thus provides the easiest entry point for theoretical modelling. Chemical and isotope substitutions at the amine support the robustness of the assignment, whereas a switch from water to methanol removes the bending-based resonance opportunities. After correction for the resonances, the OH-stretching positions of the water complex follow those of the methanol complex quite closely. This shows that methanol and water undergo similar hydrogen bond interactions with the amine. Previous contradicting spectral interpretations of water trimethylamine mixtures in supersonic jets and in argon matrices are discussed and discouraged. For the dihydrate of trimethylamine, both hydrogen-bonded OH stretching vibrations are characterised in the jet expansion.</p>","PeriodicalId":99,"journal":{"name":"Physical Chemistry Chemical Physics","volume":" 22","pages":" 11487-11491"},"PeriodicalIF":2.9000,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.rsc.org/en/content/articlepdf/2025/cp/d5cp01424g?page=search","citationCount":"0","resultStr":"{\"title\":\"OH-stretching dynamics in trimethylamine monohydrate: what can we learn from three different direct absorption spectra?†\",\"authors\":\"Taija L. Fischer, Casper V. Jensen, Eaindra Lwin, Dhritabrata Pal, Henrik G. Kjaergaard and Martin A. Suhm\",\"doi\":\"10.1039/D5CP01424G\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p >The hydrogen-bonded binary complex between water and trimethylamine is characterised in jet expansions, in the room temperature gas phase and in frozen argon matrices <em>via</em> its OH-stretching fundamental. The spectral comparison reveals two bracketing resonance partners with weak environmental dependence of their wavenumber. They correspond to the water bending overtone alone and in combination with a stretching motion of the monomers relative to each other. The environment-sensitive OH-stretching mode moves from the combination band location at room temperature all the way down to the pure water bending overtone in cryomatrix isolation, sharing its infrared intensity in proportion to the spectral vicinity and coupling strength. The intermediate jet-cooled spectrum largely removes thermal excitation and embedding effects. It thus provides the easiest entry point for theoretical modelling. Chemical and isotope substitutions at the amine support the robustness of the assignment, whereas a switch from water to methanol removes the bending-based resonance opportunities. After correction for the resonances, the OH-stretching positions of the water complex follow those of the methanol complex quite closely. This shows that methanol and water undergo similar hydrogen bond interactions with the amine. Previous contradicting spectral interpretations of water trimethylamine mixtures in supersonic jets and in argon matrices are discussed and discouraged. For the dihydrate of trimethylamine, both hydrogen-bonded OH stretching vibrations are characterised in the jet expansion.</p>\",\"PeriodicalId\":99,\"journal\":{\"name\":\"Physical Chemistry Chemical Physics\",\"volume\":\" 22\",\"pages\":\" 11487-11491\"},\"PeriodicalIF\":2.9000,\"publicationDate\":\"2025-05-14\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"https://pubs.rsc.org/en/content/articlepdf/2025/cp/d5cp01424g?page=search\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Physical Chemistry Chemical Physics\",\"FirstCategoryId\":\"92\",\"ListUrlMain\":\"https://pubs.rsc.org/en/content/articlelanding/2025/cp/d5cp01424g\",\"RegionNum\":3,\"RegionCategory\":\"化学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q3\",\"JCRName\":\"CHEMISTRY, PHYSICAL\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Physical Chemistry Chemical Physics","FirstCategoryId":"92","ListUrlMain":"https://pubs.rsc.org/en/content/articlelanding/2025/cp/d5cp01424g","RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"CHEMISTRY, PHYSICAL","Score":null,"Total":0}
OH-stretching dynamics in trimethylamine monohydrate: what can we learn from three different direct absorption spectra?†
The hydrogen-bonded binary complex between water and trimethylamine is characterised in jet expansions, in the room temperature gas phase and in frozen argon matrices via its OH-stretching fundamental. The spectral comparison reveals two bracketing resonance partners with weak environmental dependence of their wavenumber. They correspond to the water bending overtone alone and in combination with a stretching motion of the monomers relative to each other. The environment-sensitive OH-stretching mode moves from the combination band location at room temperature all the way down to the pure water bending overtone in cryomatrix isolation, sharing its infrared intensity in proportion to the spectral vicinity and coupling strength. The intermediate jet-cooled spectrum largely removes thermal excitation and embedding effects. It thus provides the easiest entry point for theoretical modelling. Chemical and isotope substitutions at the amine support the robustness of the assignment, whereas a switch from water to methanol removes the bending-based resonance opportunities. After correction for the resonances, the OH-stretching positions of the water complex follow those of the methanol complex quite closely. This shows that methanol and water undergo similar hydrogen bond interactions with the amine. Previous contradicting spectral interpretations of water trimethylamine mixtures in supersonic jets and in argon matrices are discussed and discouraged. For the dihydrate of trimethylamine, both hydrogen-bonded OH stretching vibrations are characterised in the jet expansion.
期刊介绍:
Physical Chemistry Chemical Physics (PCCP) is an international journal co-owned by 19 physical chemistry and physics societies from around the world. This journal publishes original, cutting-edge research in physical chemistry, chemical physics and biophysical chemistry. To be suitable for publication in PCCP, articles must include significant innovation and/or insight into physical chemistry; this is the most important criterion that reviewers and Editors will judge against when evaluating submissions.
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