1
|
Abstract
The ultraviolet photochemistry of the amino acids glycine, leucine, proline, and serine in their neutral forms was investigated using parahydrogen matrix-isolation spectroscopy. Irradiation by 213 nm light destroys the chirality of all three chiral amino acids as a result of the α-carbonyl C-C bond cleavage and hydrocarboxyl (HOCO) radical production. The temporal behavior of the Fourier-transform infrared spectra revealed that HOCO radicals rapidly reach a steady state, which occurs predominantly due to photodissociation of HOCO into CO + OH or CO2 + H. In glycine and leucine, the amine radicals generated by the α-carbonyl C-C bond cleavage rapidly undergo hydrogen elimination to yield methanimine and 3-methylbutane-1-imine, respectively. Breaking of the α-carbonyl C-C bond in proline appeared to yield 1-pyrroline, although due to its weak absorption it remains unconfirmed. In serine, additional products were formaldehyde and E/Z ethanimine. The present study shows that the direct production of HOCO previously observed in α-alanine generalizes to other amino acids of varying structure. It also revealed a tendency for amino acid photolysis to form imines rather than amine radicals. HOCO should be useful in the search for amino acids in interstellar space, particularly in combination with simple imine molecules.
Collapse
Affiliation(s)
- Brendan Moore
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
| | - Kyle Mahoney
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
| | - Mei Fei Zeng
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
| | - Pavle Djuricanin
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
| | - Takamasa Momose
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
| |
Collapse
|
2
|
Moore B, Toh SY, Wong YTA, Bashiri T, McKinnon A, Wai Y, Alethea Lee KW, Ovchinnikov P, Chiang CY, Djuricanin P, Momose T. Hydrocarboxyl Radical as a Product of α-Alanine Ultraviolet Photolysis. J Phys Chem Lett 2021; 12:11992-11997. [PMID: 34889613 DOI: 10.1021/acs.jpclett.1c03104] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
UV photodissociation of α-alanine was studied by parahydrogen matrix isolation infrared spectroscopy. The temporal behavior of Fourier transform infrared spectra revealed that UV irradiation at 213 nm yielded the HOCO radical as a direct photoproduct from the S2 excited state. The concentration of HOCO quickly approached a steady state due to secondary photodissociation of HOCO to produce CO2 + H or CO + OH. On the other hand, no photoproducts were detected by S1 excitation at 266 nm. Irradiation of fully deuterated α-alanine at 213 nm yielded ∼2 times more cis-DOCO radicals than the lower energy isomer trans-DOCO, indicating that the conformation of the hydroxyl group is fairly well-preserved upon photodissociation of α-alanine. The present study suggests that HOCO may be a good tracer species in the search for amino acids in interstellar space.
Collapse
Affiliation(s)
- Brendan Moore
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1, Canada
| | - Shin Yi Toh
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1, Canada
| | - Y T Angel Wong
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1, Canada
| | - Termeh Bashiri
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1, Canada
| | - Alexandra McKinnon
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1, Canada
| | - Yonnie Wai
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1, Canada
| | - Ka Wing Alethea Lee
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1, Canada
| | - Polina Ovchinnikov
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1, Canada
| | - Chih-Yu Chiang
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1, Canada
| | - Pavle Djuricanin
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1, Canada
| | - Takamasa Momose
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1, Canada
| |
Collapse
|
3
|
Tahsildaran F FS, Moore B, Bashiri T, Otani H, Djuricanin P, Malekfar R, Farahbod AH, Momose T. VUV photochemistry and nuclear spin conversion of water and water-orthohydrogen complexes in parahydrogen crystals at 4 K. Phys Chem Chem Phys 2021; 23:4094-4106. [PMID: 33586746 DOI: 10.1039/d0cp04523c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Samples of H2O, HDO, and D2O were isolated in solid parahydrogen (pH2) matrices and irradiated by vacuum ultraviolet (VUV) radiation at 147 nm. Fourier-Transform Infrared (FTIR) spectra showed a clear depletion of D2O and an enrichment of both HDO and H2O by 147 nm irradiation. These irradiation-dependent changes are attributed to the production of OH and/or OD radicals through photodissociations of H2O, HDO, and D2O. The radicals subsequently react with the hydrogen matrix, leading to the observed enrichment of H2O. No trace of isolated OH or OD was detected in the FTIR spectra, indicating that the OH/OD radicals react with the surrounding matrix hydrogen molecules via quantum tunneling within our experimental timescale. The observed temporal changes in concentrations, especially the increase of HDO concentration during VUV irradiation, can be interpreted by a model with a rapid conversion from orthohydrogen (oH2) to pH2 in water-oH2 complexes upon VUV photodissociation, indicating either the acceleration of the nuclear spin conversion (NSC) of H2 due to the magnetic moment of the intermediate OH/OD radical, or the preferential reaction of the OH/OD radical with a nearby oH2 molecule over other pH2 molecules. We have also identified and quantified an anomalously slow NSC of H2O and D2O complexed with oH2 in solid pH2.
Collapse
Affiliation(s)
- Fatemeh S Tahsildaran F
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1, Canada. and Atomic and Molecular Physics Group, Department of Physics, Faculty of Basic Sciences, Tarbiat Modares University, Tehran, Iran
| | - Brendan Moore
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1, Canada.
| | - Termeh Bashiri
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1, Canada.
| | - Hatsuki Otani
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1, Canada.
| | - Pavle Djuricanin
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1, Canada.
| | - Rasoul Malekfar
- Atomic and Molecular Physics Group, Department of Physics, Faculty of Basic Sciences, Tarbiat Modares University, Tehran, Iran
| | - Amir Hossein Farahbod
- Research School of Plasma Physics and Nuclear Fusion, Research Institute of Nuclear Sciences and Technologies, AEOI, Tehran, Iran
| | - Takamasa Momose
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1, Canada.
| |
Collapse
|
4
|
|
5
|
Abstract
With the use of solid parahydrogen in matrix isolation spectroscopy becoming more commonplace over the past few decades, it is increasingly important to understand the behavior of molecules isolated in this solid. The mobility of molecules in solid parahydrogen can play an important role in the dynamics of the system. Water molecules embedded in solid parahydrogen as deposited were found to be mobile at 4.0 K on the time scale of a few days. The diffusion at this temperature must be due to quantum tunneling in solid parahydrogen. The diffusion dynamics were analyzed based on the theory of nucleation. The concentration dependence on the diffusion rate indicates that there might be correlated motion of water molecules, a signature of quantum diffusion. We find that both water monomers and water dimers migrate in solid parahydrogen and provide insight into the behavior of molecules embedded in this quantum crystal.
Collapse
Affiliation(s)
- Brendan Moore
- Department of Chemistry , The University of British Columbia , 2036 Main Mall , Vancouver , British Columbia V6T 1Z1 , Canada
| | - Pavle Djuricanin
- Department of Chemistry , The University of British Columbia , 2036 Main Mall , Vancouver , British Columbia V6T 1Z1 , Canada
| | - Takamasa Momose
- Department of Chemistry , The University of British Columbia , 2036 Main Mall , Vancouver , British Columbia V6T 1Z1 , Canada
| |
Collapse
|
6
|
Grzesiak J, Vashishta M, Djuricanin P, Stienkemeier F, Mudrich M, Dulitz K, Momose T. Production of rotationally cold methyl radicals in pulsed supersonic beams. Rev Sci Instrum 2018; 89:113103. [PMID: 30501335 DOI: 10.1063/1.5052017] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 10/16/2018] [Indexed: 06/09/2023]
Abstract
We present a comparison of two technically distinct methods for the generation of rotationally cold, pulsed supersonic beams of methyl radicals (CH3): a plate discharge source operating in the glow regime and a dielectric barrier discharge source. The results imply that the efficiency of both sources is comparable and that molecular beams with similar translational and rotational temperatures are formed. Methane (CH4) proved to be the most suitable radical precursor species.
Collapse
Affiliation(s)
- Jonas Grzesiak
- Physikalisches Institut, Universität Freiburg, 79104 Freiburg, Germany
| | - Manish Vashishta
- Department of Chemistry, The University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - Pavle Djuricanin
- Department of Chemistry, The University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | | | - Marcel Mudrich
- Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, 8000 Aarhus C, Denmark
| | - Katrin Dulitz
- Physikalisches Institut, Universität Freiburg, 79104 Freiburg, Germany
| | - Takamasa Momose
- Department of Chemistry, The University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| |
Collapse
|
7
|
Liu Y, Vashishta M, Djuricanin P, Zhou S, Zhong W, Mittertreiner T, Carty D, Momose T. Magnetic Trapping of Cold Methyl Radicals. Phys Rev Lett 2017; 118:093201. [PMID: 28306318 DOI: 10.1103/physrevlett.118.093201] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Indexed: 06/06/2023]
Abstract
We have demonstrated that a supersonic beam of methyl radicals (CH_{3}) in the ground rotational state of both para and ortho species has been slowed down to standstill with a magnetic molecular decelerator, and successfully captured spatially in an anti-Helmholtz magnetic trap for >1 s. The trapped CH_{3} radicals have a mean translational temperature of about 200 mK with an estimated density of >5.0×10^{7} cm^{-3}. The methyl radical is an ideal system for the study of cold molecules not only because of its high reactivities at low temperatures, but also because further cooling below 1 mK is plausible via sympathetic cooling with ultracold atoms. The demonstrated trapping capability of methyl radicals opens up various possibilities for realizing ultracold ensembles of molecules towards Bose-Einstein condensation of polyatomic molecules and investigations of reactions governed by quantum statistics.
Collapse
Affiliation(s)
- Yang Liu
- Department of Chemistry, The University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - Manish Vashishta
- Department of Chemistry, The University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - Pavle Djuricanin
- Department of Chemistry, The University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - Sida Zhou
- Department of Chemistry, The University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - Wei Zhong
- Department of Physics and Astronomy, The University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - Tony Mittertreiner
- Department of Chemistry, The University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - David Carty
- Durham University, Joint Quantum Centre Durham-Newcastle, Departments of Chemistry and Physics, South Road, Durham DH1 3LE, United Kingdom
| | - Takamasa Momose
- Department of Chemistry, The University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
- Department of Physics and Astronomy, The University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| |
Collapse
|
8
|
Nourbakhsh O, Michan JM, Mittertreiner T, Carty D, Wrede E, Djuricanin P, Momose T. State purified deceleration of SD radicals by a Stark decelerator. Mol Phys 2015. [DOI: 10.1080/00268976.2015.1109151] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
|
9
|
Toh SY, Djuricanin P, Momose T, Miyazaki J. UV Photochemistry of Benzene and Cyclohexadienyl Radical in Solid Parahydrogen. J Phys Chem A 2015; 119:2683-91. [DOI: 10.1021/jp5098537] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Shin Yi Toh
- Department
of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
| | - Pavle Djuricanin
- Department
of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
| | - Takamasa Momose
- Department
of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
| | - Jun Miyazaki
- Department
of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
- Department
of Liberal Arts and Basic Sciences, College of Industrial Technology, Nihon University, 2-11-1 Shinei, Narashino, Chiba 275-8576, Japan
| |
Collapse
|
10
|
Spieler S, Zhong W, Djuricanin P, Nourbakhsh O, Gerhardt I, Enomoto K, Stienkemeier F, Momose T. Microwave lens effect for the J = 0 rotational state of CH3CN. Mol Phys 2013. [DOI: 10.1080/00268976.2013.798044] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Steffen Spieler
- a Physikalisches Institut , Universität Freiburg , Freiburg , Germany
| | - Wei Zhong
- b Department of Physics and Astronomy , The University of British Columbia , Vancouver , BC , Canada
| | - Pavle Djuricanin
- c Department of Chemistry , The University of British Columbia , Vancouver , BC , Canada
| | - Omid Nourbakhsh
- b Department of Physics and Astronomy , The University of British Columbia , Vancouver , BC , Canada
| | - Ilja Gerhardt
- c Department of Chemistry , The University of British Columbia , Vancouver , BC , Canada
| | - Katsunari Enomoto
- c Department of Chemistry , The University of British Columbia , Vancouver , BC , Canada
| | | | - Takamasa Momose
- a Physikalisches Institut , Universität Freiburg , Freiburg , Germany
- c Department of Chemistry , The University of British Columbia , Vancouver , BC , Canada
| |
Collapse
|
11
|
Momose T, Liu Y, Zhou S, Djuricanin P, Carty D. Manipulation of translational motion of methyl radicals by pulsed magnetic fields. Phys Chem Chem Phys 2013; 15:1772-7. [DOI: 10.1039/c2cp43796a] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|