Photogrammetry of Ultrafast Excited-State Intramolecular Proton Transfer Pathways in the Fungal Pigment Draconin Red
Proton transfer processes of organic molecules are key to charge transport and photoprotection in biological systems. Among them, excited-state intramolecular proton transfer (ESIPT) reactions are characterized by quick and efficient charge transfer within a molecule, resulting in ultrafast proton m...
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| Format: | Article |
| Language: | English |
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MDPI AG
2023-04-01
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| Series: | Molecules |
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| Online Access: | https://www.mdpi.com/1420-3049/28/8/3506 |
| _version_ | 1797604067353034752 |
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| author | Janak Solaris Taylor D. Krueger Cheng Chen Chong Fang |
| author_facet | Janak Solaris Taylor D. Krueger Cheng Chen Chong Fang |
| author_sort | Janak Solaris |
| collection | DOAJ |
| description | Proton transfer processes of organic molecules are key to charge transport and photoprotection in biological systems. Among them, excited-state intramolecular proton transfer (ESIPT) reactions are characterized by quick and efficient charge transfer within a molecule, resulting in ultrafast proton motions. The ESIPT-facilitated interconversion between two tautomers (PS and PA) comprising the tree fungal pigment Draconin Red in solution was investigated using a combination of targeted femtosecond transient absorption (fs-TA) and excited-state femtosecond stimulated Raman spectroscopy (ES-FSRS) measurements. Transient intensity (population and polarizability) and frequency (structural and cooling) dynamics of –COH rocking and –C=C, –C=O stretching modes following directed stimulation of each tautomer elucidate the excitation-dependent relaxation pathways, particularly the bidirectional ESIPT progression out of the Franck–Condon region to the lower-lying excited state, of the intrinsically heterogeneous chromophore in dichloromethane solvent. A characteristic overall excited-state PS-to-PA transition on the picosecond timescale leads to a unique “W”-shaped excited-state Raman intensity pattern due to dynamic resonance enhancement with the Raman pump–probe pulse pair. The ability to utilize quantum mechanics calculations in conjunction with steady-state electronic absorption and emission spectra to induce disparate excited-state populations in an inhomogeneous mixture of similar tautomers has broad implications for the modeling of potential energy surfaces and delineation of reaction mechanisms in naturally occurring chromophores. Such fundamental insights afforded by in-depth analysis of ultrafast spectroscopic datasets are also beneficial for future development of sustainable materials and optoelectronics. |
| first_indexed | 2024-03-11T04:40:56Z |
| format | Article |
| id | doaj.art-02fdd30ee8654262af9088ffc8599b89 |
| institution | Directory Open Access Journal |
| issn | 1420-3049 |
| language | English |
| last_indexed | 2024-03-11T04:40:56Z |
| publishDate | 2023-04-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Molecules |
| spelling | doaj.art-02fdd30ee8654262af9088ffc8599b892023-11-17T20:39:58ZengMDPI AGMolecules1420-30492023-04-01288350610.3390/molecules28083506Photogrammetry of Ultrafast Excited-State Intramolecular Proton Transfer Pathways in the Fungal Pigment Draconin RedJanak Solaris0Taylor D. Krueger1Cheng Chen2Chong Fang3Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, OR 97331, USADepartment of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, OR 97331, USADepartment of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, OR 97331, USADepartment of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, OR 97331, USAProton transfer processes of organic molecules are key to charge transport and photoprotection in biological systems. Among them, excited-state intramolecular proton transfer (ESIPT) reactions are characterized by quick and efficient charge transfer within a molecule, resulting in ultrafast proton motions. The ESIPT-facilitated interconversion between two tautomers (PS and PA) comprising the tree fungal pigment Draconin Red in solution was investigated using a combination of targeted femtosecond transient absorption (fs-TA) and excited-state femtosecond stimulated Raman spectroscopy (ES-FSRS) measurements. Transient intensity (population and polarizability) and frequency (structural and cooling) dynamics of –COH rocking and –C=C, –C=O stretching modes following directed stimulation of each tautomer elucidate the excitation-dependent relaxation pathways, particularly the bidirectional ESIPT progression out of the Franck–Condon region to the lower-lying excited state, of the intrinsically heterogeneous chromophore in dichloromethane solvent. A characteristic overall excited-state PS-to-PA transition on the picosecond timescale leads to a unique “W”-shaped excited-state Raman intensity pattern due to dynamic resonance enhancement with the Raman pump–probe pulse pair. The ability to utilize quantum mechanics calculations in conjunction with steady-state electronic absorption and emission spectra to induce disparate excited-state populations in an inhomogeneous mixture of similar tautomers has broad implications for the modeling of potential energy surfaces and delineation of reaction mechanisms in naturally occurring chromophores. Such fundamental insights afforded by in-depth analysis of ultrafast spectroscopic datasets are also beneficial for future development of sustainable materials and optoelectronics.https://www.mdpi.com/1420-3049/28/8/3506dyes and pigmentsnaphthoquinonesultrafast spectroscopyquantum chemical calculationsbidirectional proton transferphotochemistry |
| spellingShingle | Janak Solaris Taylor D. Krueger Cheng Chen Chong Fang Photogrammetry of Ultrafast Excited-State Intramolecular Proton Transfer Pathways in the Fungal Pigment Draconin Red Molecules dyes and pigments naphthoquinones ultrafast spectroscopy quantum chemical calculations bidirectional proton transfer photochemistry |
| title | Photogrammetry of Ultrafast Excited-State Intramolecular Proton Transfer Pathways in the Fungal Pigment Draconin Red |
| title_full | Photogrammetry of Ultrafast Excited-State Intramolecular Proton Transfer Pathways in the Fungal Pigment Draconin Red |
| title_fullStr | Photogrammetry of Ultrafast Excited-State Intramolecular Proton Transfer Pathways in the Fungal Pigment Draconin Red |
| title_full_unstemmed | Photogrammetry of Ultrafast Excited-State Intramolecular Proton Transfer Pathways in the Fungal Pigment Draconin Red |
| title_short | Photogrammetry of Ultrafast Excited-State Intramolecular Proton Transfer Pathways in the Fungal Pigment Draconin Red |
| title_sort | photogrammetry of ultrafast excited state intramolecular proton transfer pathways in the fungal pigment draconin red |
| topic | dyes and pigments naphthoquinones ultrafast spectroscopy quantum chemical calculations bidirectional proton transfer photochemistry |
| url | https://www.mdpi.com/1420-3049/28/8/3506 |
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