Effect of hydrogen bonding interaction on the photophysics of α-amino-orcein.
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| Title: | Effect of hydrogen bonding interaction on the photophysics of α-amino-orcein. |
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| Authors: | Clementi, C.1 (AUTHOR) catia.clementi@unipg.it, Carlotti, B.1 (AUTHOR), Burattini, C.1 (AUTHOR), Pellegrino, R.M.1 (AUTHOR), Romani, A.1 (AUTHOR), Elisei, F.1 (AUTHOR) |
| Source: | Spectrochimica Acta Part A: Molecular & Biomolecular Spectroscopy. May2019, Vol. 214, p522-530. 9p. |
| Subjects: | Hydrogen bonding interactions, Solvatochromism |
| Abstract: | Abstract This paper reports for the first time a detailed spectroscopic investigation into the ground- and excited-state properties of α-amino-orcein (α-AO), one of the main components of the orcein dye, in solvents of different proticity and water at different pHs. In order to gain insight into the nature of the involved transitions and excited state deactivation pathways, the study was carried out by means of UV–Visible steady state and ultrafast spectroscopic techniques with the support of quantum mechanical calculations (DFT and TDDFT). The results highlight that the photophysical and photodynamic behaviour of α-AO are highly sensitive to the solvent proticity and pH. In particular, protic environment induces a red shift (55 nm) of the absorption spectrum together with a relevant decrease of the fluorescence quantum yield (from 0.19 in acetonitrile to 6.6 × 10−3 in methanol) and radiative rate constant (two orders of magnitude). A notable red shift is also caused by increasing the pH leading the molecule from monocationic to neutral and then monoanionic form through two deprotonation steps (pKa = 3.539 ± 0.006 and 11.180 ± 0.006). Following deprotonation, the molecule assumes spectral and photophysical properties very similar to those retrieved in protic media. The observed behaviour has been rationalized through the occurrence of hydrogen bonding, likely involving to a greater extent the carbonyl oxygen of α-AO and the protic solvent, that favours the charge delocalization on the whole chromophore as well as fast non-radiative excited state deactivation. The ultrafast spectroscopic investigation revealed in fact the presence, in protic solvent, of a short living component (tens of picoseconds), assignable to solvent complexed S 1 state, alongside the long living component (few nanoseconds) observed in aprotic media and attributed to the solvent free S 1 state. The results achieved in this study for α-AO provides an important contribution to the interpretation of absorption and fluorescence features of orcein dye mixture in more complex systems (protein based substrates within the many aspects of the cultural heritage and biomedical field) where hydrogen bonds are expected to play a crucial role in mediating the interaction with the environment. Graphical abstract Unlabelled Image Highlights • Electronic properties of α-AO are highly sensitive to solvent proticity and pH. • α-AO shows high fluorescence quantum yield in aprotic environment. • Evidence of specific solvent interaction in protic media via hydrogen bonding • Spectral features of α-AO in MeOH and MeCN very similar to that of natural orcein [ABSTRACT FROM AUTHOR] |
| Copyright of Spectrochimica Acta Part A: Molecular & Biomolecular Spectroscopy is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
| Database: | Engineering Source |
| FullText | Text: Availability: 0 |
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| Header | DbId: egs DbLabel: Engineering Source An: 135353112 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: Effect of hydrogen bonding interaction on the photophysics of α-amino-orcein. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Clementi%2C+C%2E%22">Clementi, C.</searchLink><relatesTo>1</relatesTo> (AUTHOR)<i> catia.clementi@unipg.it</i><br /><searchLink fieldCode="AR" term="%22Carlotti%2C+B%2E%22">Carlotti, B.</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Burattini%2C+C%2E%22">Burattini, C.</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Pellegrino%2C+R%2EM%2E%22">Pellegrino, R.M.</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Romani%2C+A%2E%22">Romani, A.</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Elisei%2C+F%2E%22">Elisei, F.</searchLink><relatesTo>1</relatesTo> (AUTHOR) – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Spectrochimica+Acta+Part+A%3A+Molecular+%26+Biomolecular+Spectroscopy%22">Spectrochimica Acta Part A: Molecular & Biomolecular Spectroscopy</searchLink>. May2019, Vol. 214, p522-530. 9p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Hydrogen+bonding+interactions%22">Hydrogen bonding interactions</searchLink><br /><searchLink fieldCode="DE" term="%22Solvatochromism%22">Solvatochromism</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: Abstract This paper reports for the first time a detailed spectroscopic investigation into the ground- and excited-state properties of α-amino-orcein (α-AO), one of the main components of the orcein dye, in solvents of different proticity and water at different pHs. In order to gain insight into the nature of the involved transitions and excited state deactivation pathways, the study was carried out by means of UV–Visible steady state and ultrafast spectroscopic techniques with the support of quantum mechanical calculations (DFT and TDDFT). The results highlight that the photophysical and photodynamic behaviour of α-AO are highly sensitive to the solvent proticity and pH. In particular, protic environment induces a red shift (55 nm) of the absorption spectrum together with a relevant decrease of the fluorescence quantum yield (from 0.19 in acetonitrile to 6.6 × 10−3 in methanol) and radiative rate constant (two orders of magnitude). A notable red shift is also caused by increasing the pH leading the molecule from monocationic to neutral and then monoanionic form through two deprotonation steps (pKa = 3.539 ± 0.006 and 11.180 ± 0.006). Following deprotonation, the molecule assumes spectral and photophysical properties very similar to those retrieved in protic media. The observed behaviour has been rationalized through the occurrence of hydrogen bonding, likely involving to a greater extent the carbonyl oxygen of α-AO and the protic solvent, that favours the charge delocalization on the whole chromophore as well as fast non-radiative excited state deactivation. The ultrafast spectroscopic investigation revealed in fact the presence, in protic solvent, of a short living component (tens of picoseconds), assignable to solvent complexed S 1 state, alongside the long living component (few nanoseconds) observed in aprotic media and attributed to the solvent free S 1 state. The results achieved in this study for α-AO provides an important contribution to the interpretation of absorption and fluorescence features of orcein dye mixture in more complex systems (protein based substrates within the many aspects of the cultural heritage and biomedical field) where hydrogen bonds are expected to play a crucial role in mediating the interaction with the environment. Graphical abstract Unlabelled Image Highlights • Electronic properties of α-AO are highly sensitive to solvent proticity and pH. • α-AO shows high fluorescence quantum yield in aprotic environment. • Evidence of specific solvent interaction in protic media via hydrogen bonding • Spectral features of α-AO in MeOH and MeCN very similar to that of natural orcein [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Spectrochimica Acta Part A: Molecular & Biomolecular Spectroscopy is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1016/j.saa.2019.02.057 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 9 StartPage: 522 Subjects: – SubjectFull: Hydrogen bonding interactions Type: general – SubjectFull: Solvatochromism Type: general Titles: – TitleFull: Effect of hydrogen bonding interaction on the photophysics of α-amino-orcein. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Clementi, C. – PersonEntity: Name: NameFull: Carlotti, B. – PersonEntity: Name: NameFull: Burattini, C. – PersonEntity: Name: NameFull: Pellegrino, R.M. – PersonEntity: Name: NameFull: Romani, A. – PersonEntity: Name: NameFull: Elisei, F. IsPartOfRelationships: – BibEntity: Dates: – D: 05 M: 05 Text: May2019 Type: published Y: 2019 Identifiers: – Type: issn-print Value: 13861425 Numbering: – Type: volume Value: 214 Titles: – TitleFull: Spectrochimica Acta Part A: Molecular & Biomolecular Spectroscopy Type: main |
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