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Caster KL, Seifert NA, Ruscic B, Jasper AW, Prozument K. Dynamics of HCN, HNC, and HNCO Formation in the 193 nm Photodissociation of Formamide. J Phys Chem A 2024. [PMID: 39225655 DOI: 10.1021/acs.jpca.4c02232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/04/2024]
Abstract
Formamide (NH2CHO) is the simplest molecule containing a peptide linkage [-NH-C(═O)-], and it plays an essential role in the study of prebiotic chemistry. Exposure to UV irradiation allows formamide to decompose and act as a prebiotic feedstock in the formation of nucleobases and other necessary starting materials. The photodissociation mechanism of gaseous formamide at 193 nm is studied using (a) chirped-pulse Fourier transform millimeter-wave spectroscopy in the 260-290 GHz spectral region in a room-temperature flow-tube reactor at 1 μbar pressure, (b) a combination of electronic structure theory, transition state theory, and quasiclassical trajectories, and (c) the Active Thermochemical Tables. The HCN and HNC photoproducts of hydrogenated (NH2CHO) and deuterated (NH2CDO and ND2CHO) formamide precursors are examined to gain insight into the photodissociation mechanism. The theoretical investigation has characterized the main pathway leading to each of the HCN/HNC isomers from the precursor isotopologues. The theoretical branching ratio [HNC]/[HCN] = 2.1 for nascent photofragments agrees with the experiment. The effect of the postphotolysis HNC ↔ HCN isomerization on the [HNC]/[HCN] ratio is predicted. We report the experimental branching ratio [HNCO]: ([HNC] + [HCN]) = 12 ± 3 and propose that most of HNCO originates from dissociation on the S1 electronic state of formamide.
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Affiliation(s)
- Kacee L Caster
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Nathan A Seifert
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
- Department of Chemistry and Chemical & Biomedical Engineering, University of New Haven, West Haven, Connecticut 06516, United States
| | - Branko Ruscic
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Ahren W Jasper
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Kirill Prozument
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
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2
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Guo Q, Qian X, Chen J, Wu Y, Fu K, Sun Z, Zheng Z, Liu Y, Zhou Y. Synthesis and nitroxyl (HNO) donating properties of benzoxadiazole-based Piloty's acids. Nitric Oxide 2023:S1089-8603(23)00048-4. [PMID: 37217001 DOI: 10.1016/j.niox.2023.05.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 05/16/2023] [Accepted: 05/19/2023] [Indexed: 05/24/2023]
Abstract
Developing functional nitroxyl (HNO) donors play a significant role in the further exploration of endogenous HNO in biochemistry and pharmacology. In this work, two novel Piloty's acids (SBD-D1 and SBD-D2) were proposed by incorporating benzoxadiazole-based fluorophores, in order to achieve the dual-function of releasing both HNO and a fluorophore in situ. Under physiological conditions, both SBD-D1 and SBD-D2 efficiently donated HNO (t1/2 = 10.96 and 8.18 min, respectively). The stoichiometric generation of HNO was determined by both vitamin B12 and phosphine compound traps. Interestingly, due to the different substitution groups on the aromatic ring, SBD-D1 with the chlorine showed no fluorescence emission, but SBD-D2 was strongly fluorescent due to the presence of the dimethylamine group. Specifically, the fluorescent signal would decrease during the release process of HNO. Moreover, theoretical calculations were performed to understand the emission difference. A strong radiation derived from benzoxadiazole with dimethylamine group due to the large transition dipole moment (∼4.3 Debye), while the presence of intramolecular charge transfer process in the donor with chlorine group caused a small transition dipole moment (<0.1 Debye). Finally, these studies would contribute to the future design and application of novel functional HNO donors for the exploration of HNO biochemistry and pharmacology.
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Affiliation(s)
- Qingwei Guo
- Key Laboratory of Advanced Materials of Tropical Island Resources of Ministry of Education and School of Chemical Engineering and Technology, Hainan University, Haikou, Hainan, 570228, China
| | - Xin Qian
- Faculty of Materials and Manufacturing, Beijing University of Technology, Beijing, 100124, China
| | - Jiajun Chen
- Key Laboratory of Advanced Materials of Tropical Island Resources of Ministry of Education and School of Chemical Engineering and Technology, Hainan University, Haikou, Hainan, 570228, China
| | - Yangyang Wu
- Key Laboratory of Advanced Materials of Tropical Island Resources of Ministry of Education and School of Chemical Engineering and Technology, Hainan University, Haikou, Hainan, 570228, China
| | - Kun Fu
- Department of Joint Surgery, The First Affiliated Hospital of Hainan Medical University, Haikou, Hainan, 570102, China
| | - Zhicheng Sun
- Beijing Engineering Research Center of Printed Electronics, Beijing Institute of Graphic Communication, Beijing, 102600, China
| | - Zilong Zheng
- Faculty of Materials and Manufacturing, Beijing University of Technology, Beijing, 100124, China
| | - Yuanyuan Liu
- Key Laboratory of Advanced Materials of Tropical Island Resources of Ministry of Education and School of Chemical Engineering and Technology, Hainan University, Haikou, Hainan, 570228, China.
| | - Yang Zhou
- Key Laboratory of Advanced Materials of Tropical Island Resources of Ministry of Education and School of Chemical Engineering and Technology, Hainan University, Haikou, Hainan, 570228, China.
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Mishra P, Fritz SM, Herbers S, Mebel AM, Zwier TS. Gas-phase pyrolysis of trans 3-pentenenitrile: competition between direct and isomerization-mediated dissociation. Phys Chem Chem Phys 2021; 23:6462-6471. [PMID: 33729262 DOI: 10.1039/d1cp00104c] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The flash pyrolysis of trans 3-pentenenitrile (3-PN, CH3-CH[double bond, length as m-dash]CH-CH2-CN) was studied by combining the results of VUV photoionization mass spectra with broadband microwave spectra recorded as a function of the temperature of the pyrolysis tube. The two separated functional groups (vinyl and nitrile) open up isomerization as an initial step in competition with unimolecular dissociation. Primary products were detected by keeping the 3-PN concentration low and limiting reaction times to the traversal time of the gas in the pyrolysis tube (∼100 μs). The reaction is quenched and products are cooled by expansion into vacuum before interrogation over the 8-18 GHz region using chirped-pulse broadband methods. 118 nm VUV photoionization of the same reaction mixture provides a means of detecting all products with ionization potentials below 10.5 eV with minimal fragmentation. These results are combined with a detailed computational investigation of the C5H7N and related potential energy surfaces, leading to a consistent picture of the unimolecular decomposition of 3-PN. Loss of two H-atoms to form a 79 amu product is proven from its microwave transitions to contain trans-Z-2,4-pentadienenitrile, while no pyridine is observed. Methyl loss, HCN loss, and breaking the central C(2)-C(3) bond all occur following isomerization of the position of the double bond, thereby opening up low-energy pathways to these decomposition channels.
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Affiliation(s)
- Piyush Mishra
- Department of Chemistry, Purdue University, West Lafayette, IN 47907-1393, USA
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4
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Zaleski DP, Sivaramakrishnan R, Weller HR, Seifert NA, Bross DH, Ruscic B, Moore KB, Elliott SN, Copan AV, Harding LB, Klippenstein SJ, Field RW, Prozument K. Substitution Reactions in the Pyrolysis of Acetone Revealed through a Modeling, Experiment, Theory Paradigm. J Am Chem Soc 2021; 143:3124-3142. [PMID: 33615780 DOI: 10.1021/jacs.0c11677] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The development of high-fidelity mechanisms for chemically reactive systems is a challenging process that requires the compilation of rate descriptions for a large and somewhat ill-defined set of reactions. The present unified combination of modeling, experiment, and theory provides a paradigm for improving such mechanism development efforts. Here we combine broadband rotational spectroscopy with detailed chemical modeling based on rate constants obtained from automated ab initio transition state theory-based master equation calculations and high-level thermochemical parametrizations. Broadband rotational spectroscopy offers quantitative and isomer-specific detection by which branching ratios of polar reaction products may be obtained. Using this technique, we observe and characterize products arising from H atom substitution reactions in the flash pyrolysis of acetone (CH3C(O)CH3) at a nominal temperature of 1800 K. The major product observed is ketene (CH2CO). Minor products identified include acetaldehyde (CH3CHO), propyne (CH3CCH), propene (CH2CHCH3), and water (HDO). Literature mechanisms for the pyrolysis of acetone do not adequately describe the minor products. The inclusion of a variety of substitution reactions, with rate constants and thermochemistry obtained from automated ab initio kinetics predictions and Active Thermochemical Tables analyses, demonstrates an important role for such processes. The pathway to acetaldehyde is shown to be a direct result of substitution of acetone's methyl group by a free H atom, while propene formation arises from OH substitution in the enol form of acetone by a free H atom.
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Affiliation(s)
- Daniel P Zaleski
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States.,Department of Chemistry, Colgate University, Hamilton, New York 13346, United States
| | - Raghu Sivaramakrishnan
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Hailey R Weller
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States.,Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Nathan A Seifert
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - David H Bross
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Branko Ruscic
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Kevin B Moore
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Sarah N Elliott
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Andreas V Copan
- Emmanuel College, Natural Sciences Department, Franklin Springs, Georgia 30639, United States
| | - Lawrence B Harding
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Stephen J Klippenstein
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Robert W Field
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Kirill Prozument
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
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5
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Zaleski DP, Prozument K. Automated assignment of rotational spectra using artificial neural networks. J Chem Phys 2018; 149:104106. [DOI: 10.1063/1.5037715] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Daniel P. Zaleski
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439,
USA
| | - Kirill Prozument
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439,
USA
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6
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Abeysekera C, Hernandez-Castillo A, Stanton JF, Zwier TS. Broadband Microwave Spectroscopy of 2-Furanyloxy Radical: Primary Pyrolysis Product of the Second-Generation Biofuel 2-Methoxyfuran. J Phys Chem A 2018; 122:6879-6885. [PMID: 30063137 DOI: 10.1021/acs.jpca.8b05102] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Chamara Abeysekera
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907, United States
| | - A.O. Hernandez-Castillo
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907, United States
| | - John F. Stanton
- Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, Florida 32611, United States
| | - Timothy S. Zwier
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907, United States
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7
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Adas SK, Bharadwaj V, Zhou Y, Zhang J, Seed AJ, Brasch NE, Sampson P. Synthesis and HNO Donating Properties of the Piloty's Acid Analogue Trifluoromethanesulphonylhydroxamic Acid: Evidence for Quantitative Release of HNO at Neutral pH Conditions. Chemistry 2018. [DOI: 10.1002/chem.201800662] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Sonya K. Adas
- Department of Chemistry and Biochemistry Kent State University Kent OH 44242 USA
| | - Vinay Bharadwaj
- School of Science Auckland University of Technology Private Bag 92006 Auckland 1142 New Zealand
| | - Yang Zhou
- Department of Chemistry and Biochemistry Kent State University Kent OH 44242 USA
| | - Jiuhong Zhang
- Department of Chemistry and Biochemistry Kent State University Kent OH 44242 USA
| | - Alexander J. Seed
- Department of Chemistry and Biochemistry Kent State University Kent OH 44242 USA
| | - Nicola E. Brasch
- School of Science Auckland University of Technology Private Bag 92006 Auckland 1142 New Zealand
| | - Paul Sampson
- Department of Chemistry and Biochemistry Kent State University Kent OH 44242 USA
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Zaleski DP, Harding LB, Klippenstein SJ, Ruscic B, Prozument K. Time-Resolved Kinetic Chirped-Pulse Rotational Spectroscopy in a Room-Temperature Flow Reactor. J Phys Chem Lett 2017; 8:6180-6188. [PMID: 29193976 DOI: 10.1021/acs.jpclett.7b02864] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Chirped-pulse Fourier transform millimeter-wave spectroscopy is a potentially powerful tool for studying chemical reaction dynamics and kinetics. Branching ratios of multiple reaction products and intermediates can be measured with unprecedented chemical specificity; molecular isomers, conformers, and vibrational states have distinct rotational spectra. Here we demonstrate chirped-pulse spectroscopy of vinyl cyanide photoproducts in a flow tube reactor at ambient temperature of 295 K and pressures of 1-10 μbar. This in situ and time-resolved experiment illustrates the utility of this novel approach to investigating chemical reaction dynamics and kinetics. Following 193 nm photodissociation of CH2CHCN, we observe rotational relaxation of energized HCN, HNC, and HCCCN photoproducts with 10 μs time resolution and sample the vibrational population distribution of HCCCN. The experimental branching ratio HCN/HCCCN is compared with a model based on RRKM theory using high-level ab initio calculations, which were in turn validated by comparisons to Active Thermochemical Tables enthalpies.
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Affiliation(s)
- Daniel P Zaleski
- Chemical Sciences and Engineering Division, Argonne National Laboratory , Argonne, Illinois 60439, United States
| | - Lawrence B Harding
- Chemical Sciences and Engineering Division, Argonne National Laboratory , Argonne, Illinois 60439, United States
| | - Stephen J Klippenstein
- Chemical Sciences and Engineering Division, Argonne National Laboratory , Argonne, Illinois 60439, United States
| | - Branko Ruscic
- Chemical Sciences and Engineering Division, Argonne National Laboratory , Argonne, Illinois 60439, United States
| | - Kirill Prozument
- Chemical Sciences and Engineering Division, Argonne National Laboratory , Argonne, Illinois 60439, United States
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