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Sharma A, Gupta VK, Reva I. Methoxyacetone revisited. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2024; 308:123651. [PMID: 38056186 DOI: 10.1016/j.saa.2023.123651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Revised: 11/10/2023] [Accepted: 11/12/2023] [Indexed: 12/08/2023]
Abstract
Conformational space of methoxyacetone (MA) was studied at the MP2/6-311++G(d,p) and DFT(B3LYP)/6-311++G(d,p) levels of theory. Computations predict MA to adopt four conformations, resulting from internal rotations around the O=C-C-O (Trans, Cis) and C-C-O-C (trans, gauche) dihedral angles. The Tt (Trans-trans) conformer is the most stable. The computed energies of two gauche (Tg and Cg) conformers fall in the 3-8 kJ mol-1 range above Tt and should account for 1/3 of the room-temperature gas-phase equilibrium. The energy of Ct form is 11 kJ mol-1 above Tt, and its expected population is negligible (below 1 %). In our earlier work, MA monomers were isolated in cryogenic argon matrices and characterized by infrared spectroscopy. In the experiment, only the most stable Tt conformer was detected in the sample. Signatures of the other conformers were not detected, either in freshly deposited samples, or in samples subjected to different UV irradiations. We rationalize those observations in terms of computed barriers for intramolecular torsions, indicating occurrence of conformational cooling during deposition. The experimental infrared spectrum of the Tt form is now assigned with the aid of anharmonic DFT computations. Exposure of MA to UV irradiation in the 300-260 nm range led to photolysis, according to the Norrish type II mechanism, resulting in dimer between enol acetone and formaldehyde observed as a cage-confined intermediate photoproduct. The subsequent photolysis resulted in the formation of carbon monoxide as the dominating photoproduct, formed in the Norrish type I photoreaction. Mechanistic interpretation of this photo decarbonylation reaction is presented.
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Affiliation(s)
- Archna Sharma
- PG Department of Physics, University of Jammu, Jammu, J&K 180006, India
| | - Vivek K Gupta
- PG Department of Physics, University of Jammu, Jammu, J&K 180006, India
| | - Igor Reva
- CIEPQPF, Department of Chemical Engineering, Rua Sílvio Lima, University of Coimbra, Coimbra 3030-790, Portugal.
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Lopes Jesus AJ, Fausto R, Reva I. Conformational Space, IR-Induced, and UV-Induced Chemistry of Carvacrol Isolated in a Low-Temperature Argon Matrix. J Phys Chem A 2021; 125:8215-8229. [PMID: 34506137 DOI: 10.1021/acs.jpca.1c05907] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
In this work, monomers of carvacrol (5-isopropyl-2-methylphenol), a natural monoterpene exhibiting wide range bioactivity, were trapped in a cryogenic argon matrix and characterized by infrared spectroscopy, while quantum chemical calculations at the B3LYP and MP2 levels were employed to characterize the conformational landscape of the isolated molecule. Four conformers have been localized on the potential energy surface, and the factors accounting for their relative stability were analyzed. The two most stable conformers of carvacrol, differing in the relative orientation of the isopropyl group and both having the OH group pointing away from the vicinal methyl fragment, were identified in the cryomatrix for the first time. The individual spectral signatures of the two conformers were distinguished based on the change in their relative abundance induced by exposing the matrix to broadband infrared light. Matrix-isolated carvacrol was also irradiated with broadband UV light (λ > 200 nm), which resulted in the cleavage of the OH group. Recombination of the released H atom at the ortho- or para-position of the ring resulted in the formation of alkyl-substituted cyclohexadienones. These were found to undergo subsequent valence and open-ring isomerizations, leading, respectively, to the formation of a Dewar isomer and open-chain conjugated ketenes. Decarbonylation of the photoproducts was also observed for longer irradiation times. A mechanistic analysis of the observed photochemical transformations is presented.
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Affiliation(s)
- A J Lopes Jesus
- University of Coimbra, CQC, Faculty of Pharmacy, 3004-295 Coimbra, Portugal
| | - Rui Fausto
- University of Coimbra, CQC, Department of Chemistry, 3004-535 Coimbra, Portugal
| | - Igor Reva
- University of Coimbra, CQC, Department of Chemistry, 3004-535 Coimbra, Portugal.,University of Coimbra, CIEPQPF, Department of Chemical Engineering, 3030-790 Coimbra, Portugal
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Rostkowska H, Lapinski L, Nowak MJ. Photochemical Generation of Benzoazetinone by UV Excitation of Matrix-Isolated Precursors: Isatin or Isatoic Anhydride. J Phys Chem A 2020; 124:4106-4114. [PMID: 32320240 PMCID: PMC7590977 DOI: 10.1021/acs.jpca.0c02562] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
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Benzoazetinone
was photochemically generated by UV irradiation
of isatin isolated in low-temperature Ar matrixes. Upon UV (λ
= 278 nm) excitation of isatin, monomers of the compound underwent
decarbonylation and the remaining part of the molecule adopted the
benzoazetinone structure or the structure of its open-ring isomer
α-iminoketene. The same products (benzoazetinone and α-iminoketene)
were generated by UV (λ = 278 nm) induced decarboxylation of
matrix-isolated monomers of isatoic anhydride. Photoproduced α-iminoketene
appeared in the low-temperature matrixes as a mixture of syn and anti
isomers. Photoproducts generated upon λ = 278 nm irradiation
of matrix-isolated isatin were subsequently exposed to λ = 532
nm light. That irradiation resulted in the shift of the α-iminoketene–benzoazetinone
population ratio in favor of the latter closed-ring structure. The
next irradiation at 305 nm caused the shift of the α-iminoketene–benzoazetinone
population ratio in the opposite direction, that is, in favor of the
open-ring isomer. Neither benzoazetinone nor its α-iminoketene
open-ring isomer was generated upon UV (λ = 278 nm) irradiation
of phthalimide isolated in Ar matrixes. Instead, the UV-excited monomers
of this compound underwent such phototransformations as oxo → hydroxy phototautomerism
or degradation
of the five-membered ring with release of HNCO and CO. The efficiency
of these photoconversions was low.
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Affiliation(s)
- Hanna Rostkowska
- Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw, Poland
| | - Leszek Lapinski
- Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw, Poland
| | - Maciej J. Nowak
- Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw, Poland
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Lapinski L, Reva I, Gerega A, Nowak MJ, Fausto R. UV-induced transformations of matrix-isolated 6-azacytosine. J Chem Phys 2018; 149:104301. [DOI: 10.1063/1.5045735] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Affiliation(s)
- Leszek Lapinski
- Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw, Poland
| | - Igor Reva
- CQC, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
| | - Anna Gerega
- Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw, Poland
- Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, Trojdena 4, 02-109 Warsaw, Poland
| | - Maciej J. Nowak
- Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668 Warsaw, Poland
| | - Rui Fausto
- CQC, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
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Highly Efficient and Stable Novel NanoBiohybrid Catalyst to Avert 3,4-Dihydroxybenzoic Acid Pollutant in Water. Sci Rep 2016; 6:33572. [PMID: 27721429 PMCID: PMC5056344 DOI: 10.1038/srep33572] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 08/25/2016] [Indexed: 11/08/2022] Open
Abstract
The present study reported for the first time covalent immobilization of protocatechuate 3,4-dioxygenase (3,4-POD) onto functionalized multi-walled carbon nanotubes (F-MWCNT) for degrading the toxic 3,4-dihydroxybenzoic acid (3,4-DHBA) pollutant in water. The F-MWCNTs had a maximum 3,4-POD loading of 1060 μg/mg. Immobilized 3,4 POD had 44% of relative structural changes to its free configurations. Nevertheless, >90% of relative activity and about 50% of catalytic efficiency were retained to the free enzyme. Immobilized 3,4-POD demonstrated higher alkaline stability and thermostability than the free 3,4-POD. The free and immobilized 3,4-POD lost 82% and 66% of relative activities, respectively after 180 min of incubations at 90 °C. Excellent shelf-life was observed for the immobilized 3,4-POD with residual activity of 56% compared with 41% and 39% of the free 3,4-POD at 4 °C and 25 °C over 30 days storage. Immobilized 3,4-POD showed >60% of catalytic activity retention even after ten-cycle uses, defraying the expenses of free 3,4-POD productions for long term uses. Finally, the immobilized 3,4-POD removed 71% of 3,4-DHBA from water in <4 h, paving its future application for water purification with reduced costs and time.
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Araujo-Andrade C, Gómez-Zavaglia A, Reva ID, Fausto R. Conformers, Infrared Spectrum and UV-Induced Photochemistry of Matrix-Isolated Furfuryl Alcohol. J Phys Chem A 2012; 116:2352-65. [DOI: 10.1021/jp212169b] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- C. Araujo-Andrade
- Unidad Académica de Física de la Universidad Autónoma de Zacatecas, Zacatecas, Mexico
| | - A. Gómez-Zavaglia
- Centro de Investigación y Desarrollo en Criotecnología de Alimentos (Conicet La Plata, UNLP), 1900 La Plata, Argentina
- Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
| | - I. D. Reva
- Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
| | - R. Fausto
- Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
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Emel’yanenko VN, Stepurko EN, Verevkin SP, Roganov GN. The thermodynamic properties of 1,4-dioxane-2,6-dione. RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY A 2011. [DOI: 10.1134/s0036024411020117] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Marzec KM, Reva I, Fausto R, Malek K, Proniewicz LM. Conformational Space and Photochemistry of α-Terpinene. J Phys Chem A 2010; 114:5526-36. [DOI: 10.1021/jp100770v] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- K. M. Marzec
- Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Krakow, Poland, and Departament of Chemistry, University of Coimbra, P-3004-535 Coimbra, Portugal
| | - I. Reva
- Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Krakow, Poland, and Departament of Chemistry, University of Coimbra, P-3004-535 Coimbra, Portugal
| | - R. Fausto
- Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Krakow, Poland, and Departament of Chemistry, University of Coimbra, P-3004-535 Coimbra, Portugal
| | - K. Malek
- Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Krakow, Poland, and Departament of Chemistry, University of Coimbra, P-3004-535 Coimbra, Portugal
| | - L. M. Proniewicz
- Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Krakow, Poland, and Departament of Chemistry, University of Coimbra, P-3004-535 Coimbra, Portugal
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