1
|
Arandhara M, Ramesh SG. Nuclear quantum effects in gas-phase ethylene glycol. Phys Chem Chem Phys 2024; 26:19529-19542. [PMID: 38979630 DOI: 10.1039/d4cp00700j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/10/2024]
Abstract
Path integral molecular simulations are used to explore the nuclear quantum effects (NQEs) on the structure, dihedral landscape and infrared spectrum of ethylene glycol. The simulations are carried out on a new reaction surface Hamiltonian-based model potential energy surface, with special focus on the role of the OCCO and HOCC dihedrals. In contrast with classical simulations, we analyse how the intramolecular interactions between the OH groups change due to zero-point effects as well as temperature. These are found to be weak. The NQEs on the free energy profile along the OCCO dihedral are analysed, where notable effects are seen at low temperatures and found to be correlated with the radii of gyration of the atoms. Finally, the power spectrum of the molecule from path integral simulations is compared with the experimental infrared spectrum, yielding a good agreement of band positions.
Collapse
Affiliation(s)
- Mrinal Arandhara
- Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560012, India.
| | - Sai G Ramesh
- Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560012, India.
| |
Collapse
|
2
|
Huang QR, Yano K, Yang Y, Fujii A, Kuo JL. Near-infrared spectroscopy of H 3O +⋯X n (X = Ar, N 2, and CO, n = 1-3). Phys Chem Chem Phys 2024; 26:10757-10768. [PMID: 38516880 DOI: 10.1039/d4cp00458b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/23/2024]
Abstract
Near-infrared (NIR) spectra of H3O+⋯Xn (X = Ar, N2, and CO, n = 1-3) in the first overtone region of OH-stretching vibrations (4800-7000 cm-1) were measured. Not only OH-stretching overtones but also several combination bands are major features in this region, and assignments of these observed bands are not obvious at a glance. High-precision anharmonic vibrational simulations based on the discrete variable representation approach were performed. The simulated spectra show good agreement with the observed ones and provide firm assignments of the observed bands, except in the case of X = CO, in which higher order vibrational mode couplings seem significant. This agreement demonstrates that the present system can be a benchmark for high precision anharmonic vibrational computations of NIR spectra. Band broadening in the observed spectra becomes remarkable with an increase of the interaction with the solvent molecule (X). The origin of the band broadening is explored by rare gas tagging experiments and anharmonic vibrational simulations of hot bands.
Collapse
Affiliation(s)
- Qian-Rui Huang
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, Taiwan.
| | - Kazuyoshi Yano
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai, Japan.
| | - Yaodi Yang
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai, Japan.
| | - Asuka Fujii
- Department of Chemistry, Graduate School of Science, Tohoku University, Sendai, Japan.
| | - Jer-Lai Kuo
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, Taiwan.
| |
Collapse
|
3
|
Yang N, Huchmala RM, McCoy AB, Johnson MA. Character of the OH Bend-Stretch Combination Band in the Vibrational Spectra of the "Magic" Number H 3O +(H 2O) 20 and D 3O +(D 2O) 20 Cluster Ions. J Phys Chem Lett 2022; 13:8116-8121. [PMID: 35998327 DOI: 10.1021/acs.jpclett.2c02318] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The fundamental transitions that contribute to the diffuse OH stretching spectrum of water are known to increase in width and intensity with increasing red shift from the free OH frequency. In contrast, the profile of the higher-energy combination band involving the OH stretching and the intramolecular HOH bending modes displays a qualitatively different spectral shape with a much faster falloff on the lower-energy side. We elucidate the molecular origin of this difference by analyzing the shapes of the combination bands in the IR spectra of cryogenically cooled H3O+(H2O)20 and D3O+(D2O)20 clusters. The difference in the shapes of the bands is traced to differences in the dependence of their transition dipole matrix elements on the hydrogen-bonding environment. The fact that individual transitions across the combination band envelope have similar intensities makes it a useful way to determine the participation of various sites in extended H-bonding networks.
Collapse
Affiliation(s)
- Nan Yang
- Sterling Chemistry Laboratory, Yale University, New Haven, Connecticut 06520, United States
| | - Rachel M Huchmala
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Anne B McCoy
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Mark A Johnson
- Sterling Chemistry Laboratory, Yale University, New Haven, Connecticut 06520, United States
| |
Collapse
|
4
|
Moissidou D, Derricott H, Kamel G. Mummified embalmed head skin: SR-FTIR microspectroscopic exploration. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2021; 261:120073. [PMID: 34147735 DOI: 10.1016/j.saa.2021.120073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 06/06/2021] [Accepted: 06/09/2021] [Indexed: 06/12/2023]
Abstract
This case report details the examination of the skin of an Egyptian mummified head with a possible skin disorder. The head, thought to be dated in the first half of the 18th Dynasty, New Kingdom (1570-1400 BCE) belongs to the Museum of Forensic Anthropology, University of Madrid. Initial histological examination demonstrated evidence of chronic inflammation, which was confirmed by immunohistochemistry and Transmission Electron Microscopy (TEM). However, confirmation of pathology could be confounded by both the age of the specimen and the process of preservation by mummification. In this case report, Synchrotron Radiation Fourier Transform Microspectroscopy (SR-µFTIR) was used to add novel insights into embalmed mummified tissue. More precisely, FTIR is used for the first time on the specific specimens, while no other similar studies have been performed on these samples priorly. Additionally, modern skin tissue was examined too, in order to compare the amount of degradation to the mummified one. Whilst the FTIR results confirmed the results from the initial histological study, they also showed a biochemical modification of the mummified skin that could be indicative of tissue degradation. The latter was supported by comparing it to FTIR results of the modern tissue used.
Collapse
Affiliation(s)
- Despina Moissidou
- Barts and the London School of Medicine and Dentistry, Queen Mary University of London, Malta Campus, Malta
| | - Hayley Derricott
- Barts and the London School of Medicine and Dentistry, Queen Mary University of London, Malta Campus, Malta
| | - Gihan Kamel
- SESAME (Synchrotron-light for Experimental Science and Applications in the Middle East), Allan, Jordan; Department of Physics, Faculty of Science, Helwan University, Cairo, Egypt.
| |
Collapse
|
5
|
Hartwig B, Suhm MA. Subtle hydrogen bonds: benchmarking with OH stretching fundamentals of vicinal diols in the gas phase. Phys Chem Chem Phys 2021; 23:21623-21640. [PMID: 34580694 DOI: 10.1039/d1cp03367k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The theoretical description of spectral signatures for weakly bound hydrogen contacts between alcohol groups is challenging and remains poorly characterised. By combining Raman jet spectroscopy with appropriately scaled harmonic DFT predictions and relaxation path analyses for 16 vicinal diols (ethylene glycol (ethane-1,2-diol), propane-1,2-diol, 3,3,3-trifluoro-propane-1,2-diol, rac-butane-2,3-diol, 2-methyl-propane-1,2-diol, 2-methyl-butane-2,3-diol, pinacol (2,3-dimethyl-butane-2,3-diol), 3-butene-1,2-diol, 1-phenyl-ethane-1,2-diol, trans-cyclobutane-1,2-diol, trans-cyclopentane-1,2-diol, trans-cyclohexane-1,2-diol, trans-cycloheptane-1,2-diol, cis-cyclohexane-1,2-diol, 1-(1-hydroxy-1-methylethyl)-cyclopentanol and [1,1'-bicyclopentyl]-1,1'-diol), 69 conformational assignments become possible in a two-tier approach with a 5 diol training and an 11 diol test set. The latter reveals systematic deviations for ring strain and secondary π interactions, but otherwise a remarkably robust correction and correlation model based on hybrid DFT with a minimally augmented triple-zeta basis set is obtained, whereas GGA functionals perform significantly worse. Raw experimental data in the 3560-3700 cm-1 wavenumber range as well as computed geometries of all conformations invite further vibrational and structural benchmarking at the onset of hydrogen bonding. Beyond this diol-probed threshold, the accurate prediction of hydrogen bond induced shifts of different magnitudes remains one of the challenges for DFT functionals.
Collapse
Affiliation(s)
- Beppo Hartwig
- Institut für Physikalische Chemie, Tammannstr. 6, Göttingen, Germany.
| | - Martin A Suhm
- Institut für Physikalische Chemie, Tammannstr. 6, Göttingen, Germany.
| |
Collapse
|
6
|
Zhang P, Ji H, Wang H, Liu Y, Zhang X, Ren C. Quantitative evaluation of impact damage to apples using NIR hyperspectral imaging. INTERNATIONAL JOURNAL OF FOOD PROPERTIES 2021. [DOI: 10.1080/10942912.2021.1900240] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Peipei Zhang
- School of Mechanical Engineering, Tianjin University, Tianjin, China
| | - Hongwei Ji
- School of Mechanical Engineering, Tianjin University, Tianjin, China
- Tianjin Key Laboratory of Refrigeration Technology, Tianjin University of Commerce, Tianjin, China
| | - Huaiwen Wang
- Tianjin Key Laboratory of Refrigeration Technology, Tianjin University of Commerce, Tianjin, China
| | - Yuexuan Liu
- Tianjin Key Laboratory of Refrigeration Technology, Tianjin University of Commerce, Tianjin, China
| | - Xiaochuan Zhang
- Tianjin Key Laboratory of Refrigeration Technology, Tianjin University of Commerce, Tianjin, China
| | - Chunhua Ren
- Tianjin Key Laboratory of Refrigeration Technology, Tianjin University of Commerce, Tianjin, China
| |
Collapse
|
7
|
Tsuyuki M, Furudate S, Kugaya Y, Yabushita S. Graphical Transition Moment Decomposition and Conceptual Density Functional Theory Approaches to Study the Fundamental and Lower-Level Overtone Absorption Intensities of Some OH Stretching Vibrations. J Phys Chem A 2021; 125:2101-2113. [PMID: 33663218 DOI: 10.1021/acs.jpca.0c11619] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The investigation of electron density migrations caused by molecular structure changes is of central importance in various fields of chemistry. To address this topic in general and to study absorption intensities of vibrations, we analyze sensitive dipole moment functions (DMFs) of a molecule by combining the linear response function of conceptual DFT and bond dipoles separated by the quantum theory of atoms in molecules with a graphical transition moment decomposition scheme. The fundamental intensities of OH stretching vibrations depend strongly on the substituents but only weakly on the molecular conformations. Interestingly, in some alcohols, completely opposite trends have been observed for the lower-level overtone intensities: a weak substituent dependence but a stronger conformation dependence. It is well known that the formation of a hydrogen-bonded complex increases the OH stretching fundamental intensity, but less well known is the decrease in their overtone intensities. To investigate these characteristics comprehensively, we calculated their intensities (Δv = 1, 2, and 3) for conformers of ethanol and trifluoroethanol (TFE) and hydrogen-bonded phenol (PhOH) systems via the DFT method in the local mode model for the OH stretching coordinate ΔR. Their first and second derivatives of the electron density with respect to ΔR were calculated and interpreted using their bond moments. For ethanol and TFE, the OH, CC, and CH bond moments were found to make an important contribution to the molecular DMF derivatives parallel to the OH bond. The OH bond contributes only to the first derivative of DMF, and its conformational dependence is determined by the magnitude of the charge polarization of each structure. The electron density derivatives in the CC bond region were largely maintained during the internal rotation; thus, their conformation-dependent contributions were expressed by a geometrical factor of the CC bond direction. The CH bond at the antiperiplanar position of the OH bond was found to make a remarkably large contribution to the second derivative of DMF in the gauche conformer. The importance of electron density migration on substituents was also identified in the hydrogen-bonded phenol, in which the π-electron density change on the aromatic ring was clearly shown. This migration creates the DMF derivatives both perpendicular and parallel to the OH bond and strongly affects the absorption intensities. In all the cases, some bond moments on the substituents contribute to the first and second DMF derivatives in a structure-dependent manner, thus explaining their stereoelectronic effects.
Collapse
Affiliation(s)
- Masafumi Tsuyuki
- Department of Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-Ku, Yokohama 223-8522, Japan
| | - Shunki Furudate
- Department of Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-Ku, Yokohama 223-8522, Japan
| | - Yuto Kugaya
- Department of Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-Ku, Yokohama 223-8522, Japan
| | - Satoshi Yabushita
- Department of Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-Ku, Yokohama 223-8522, Japan
| |
Collapse
|
8
|
Moosavi-Nasab M, Khoshnoudi-Nia S, Azimifar Z, Kamyab S. Evaluation of the total volatile basic nitrogen (TVB-N) content in fish fillets using hyperspectral imaging coupled with deep learning neural network and meta-analysis. Sci Rep 2021; 11:5094. [PMID: 33658634 PMCID: PMC7930251 DOI: 10.1038/s41598-021-84659-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Accepted: 01/25/2021] [Indexed: 11/09/2022] Open
Abstract
Recently, hyperspectral-imaging (HSI), as a rapid and non-destructive technique, has generated much interest due to its unique potential to monitor food quality and safety. The specific aim of the study is to investigate the potential of the HSI (430-1010 nm) coupled with Linear Deep Neural Network (LDNN) to predict the TVB-N content of rainbow trout fillet during 12 days storage at 4 ± 2 °C. After the acquisition of hyperspectral images, the TVB-N content of fish fillets was obtained by a conventional method (micro-Kjeldahl distillation). To simplify the calibration models, nine optimal wavelengths were selected by the successive projections algorithm. A seven layers LDNN was designed to estimate the TVB-N content of samples. The LDNN model showed acceptable performance for prediction of TVB-N content of fish fillet (R2p = 0.853; RSMEP = 3.159 and RDP = 3.001). The performance of LDNN model was comparable with the results of previous works. Although, the results of the meta-analysis did not show any significant difference between various chemometric models. However, the least-squares support vector machine algorithm showed better prediction results as compared to the other models (RMSEP: 2.63 and R2p = 0.897). Further studies are required to improve the prediction power of the deep learning model for prediction of rainbow-trout fish quality.
Collapse
Affiliation(s)
- Marzieh Moosavi-Nasab
- Seafood Processing Research Group, Department of Food Science and Technology, School of Agriculture, Shiraz University, P.O. Box 71441-65186, Shiraz, Iran.
| | - Sara Khoshnoudi-Nia
- Seafood Processing Research Group, School of Agriculture, Shiraz University, P.O. Box 71441-65186, Shiraz, Iran
| | - Zohreh Azimifar
- Department of Computer Science and Engineering, Shiraz University, P.O. Box 71936-16548, Shiraz, Iran
| | - Shima Kamyab
- Department of Computer Science and Engineering, Shiraz University, P.O. Box 71936-16548, Shiraz, Iran
| |
Collapse
|
9
|
Frandsen BN, Deal AM, Lane JR, Vaida V. Lactic Acid Spectroscopy: Intra- and Intermolecular Interactions. J Phys Chem A 2020; 125:218-229. [PMID: 33377780 DOI: 10.1021/acs.jpca.0c09341] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Lactic acid, a relevant molecule in biology and the environment, is an α-hydroxy acid with a high propensity to form hydrogen bonds, both internally and to other hydrogen-bond-accepting molecules. This work includes the novel recording of infrared spectra of gas-phase lactic acid using Fourier transform infrared spectroscopy, and the vibrational absorption features of lactic acid are assigned with the aid of computationally simulated vibrational spectra with anharmonic corrections. Theoretical chemistry methods are used to relate intramolecular hydrogen-bond strengths to the relative stability of lactic acid conformers. The formation of hydrogen-bonded lactic acid dimers and 1:1 water complexes is investigated by simulated vibrational spectra and calculated thermodynamic parameters for the lactic acid monomer and dimer and its water complex in the gas phase. The results of this study are discussed in the context of environmental chemistry with an emphasis on indoor environments.
Collapse
Affiliation(s)
- Benjamin N Frandsen
- Department of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States.,Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, UCB 216, Boulder, Colorado 80309, United States
| | - Alexandra M Deal
- Department of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States.,Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, UCB 216, Boulder, Colorado 80309, United States
| | - Joseph R Lane
- School of Science, University of Waikato, Private Bag 3105, Hamilton 3240, New Zealand
| | - Veronica Vaida
- Department of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States.,Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, UCB 216, Boulder, Colorado 80309, United States
| |
Collapse
|
10
|
Liu Q, Zhou D, Tu S, Xiao H, Zhang B, Sun Y, Pan L, Tu K. Quantitative Visualization of Fungal Contamination in Peach Fruit Using Hyperspectral Imaging. FOOD ANAL METHOD 2020. [DOI: 10.1007/s12161-020-01747-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
11
|
Khoshnoudi-Nia S, Moosavi-Nasab M. Prediction of various freshness indicators in fish fillets by one multispectral imaging system. Sci Rep 2019; 9:14704. [PMID: 31605023 PMCID: PMC6789145 DOI: 10.1038/s41598-019-51264-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Accepted: 09/29/2019] [Indexed: 01/16/2023] Open
Abstract
In current study, a simple multispectral imaging (430–1010 nm) system along with linear and non-linear regressions were used to assess the various fish spoilage indicators during 12 days storage at 4 ± 2 °C. The indicators included Total-Volatile Basic Nitrogen (TVB-N) and Psychrotrophic Plate Count (PPC) and sensory score in fish fillets. immediately, after hyperspectral imaging, the reference values (TVB-N, PPC and sensory score) of samples were obtained by traditional method. To simplify the calibration models, nine optimal wavelengths were selected by genetic algorithm. The prediction performance of various chemometric models including partial least-squares regression (PLSR), multiple-linear regression (MLR), least-squares support vector machine (LS-SVM) and back-propagation artificial neural network (BP-ANN) were compared. All models showed acceptable performance for simultaneous predicting of PPC, TVB-N and sensory score (R2P ≥ 0.853 and RPD ≥ 2.603). Non-linear models were considered better quantitative model to predict all of three freshness indicators in fish fillets. Among the three spoilage indices, the best predictive power was obtained for PPC value and the weakest one was acquired for TVB-N content prediction. The best model for prediction TVB-N (R2p = 0.862; RMSEP = 3.542 and RPD = 2.678) and sensory score (R2p = 0.912; RMSEP = 1.802 and RPD = 3.33) belonged to GA-LS-SVM and for prediction of PPC value was BP-ANN (R2p = 0.921; RMSEP = 0.504 and RPD = 3.64). Therefore, developing multispectral imaging system based on LS-SVM model seems to be suitable for simultaneous prediction of all three indicators (R2P > 0.862 and RPD > 2.678). Further studies needed to improve the accuracy and applicability of HSI system for predicting freshness of rainbow-trout fish.
Collapse
Affiliation(s)
- Sara Khoshnoudi-Nia
- Seafood Processing Research Group, School of Agriculture, Shiraz University, PO Box: 71441-65186, Shiraz, Iran.
| | - Marzieh Moosavi-Nasab
- Seafood Processing Research Group & Department of Food Science and Technology, School of Agriculture, Shiraz University, PO Box: 71441-65186, Shiraz, Iran.
| |
Collapse
|
12
|
Khoshnoudi‐Nia S, Moosavi‐Nasab M. Comparison of various chemometric analysis for rapid prediction of thiobarbituric acid reactive substances in rainbow trout fillets by hyperspectral imaging technique. Food Sci Nutr 2019; 7:1875-1883. [PMID: 31139402 PMCID: PMC6526668 DOI: 10.1002/fsn3.1043] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Revised: 03/13/2019] [Accepted: 03/27/2019] [Indexed: 12/31/2022] Open
Abstract
This study explores the potential application of hyperspectral imaging (HSI; 430-1,010 nm) coupled with different linear and nonlinear models for rapid nondestructive evaluation of thiobarbituric acid-reactive substances (TBARS) value in rainbow trout (Oncorhynchus mykiss) fillets during 12 days of cold storage (4 ± 2°C). HSI data and TBARS value of fillets were obtained in the laboratory. The primary prediction models were established based on linear partial least squares regression (PLSR) and least squares support vector machine (LS-SVM). In full spectral range, the prediction capability of LS-SVM ( R P 2 = 0.829; RMSEP = 0.128 mg malondialdehyde [MDA]/kg) was better than PLSR ( R P 2 = 0.748; RMSEP = 0.155 mg MDA/kg) model and LS-SVM model exhibited satisfactory prediction performance ( R P 2 > 0.82). To simplify the calibration models, a combination of uninformative variable elimination and backward regression (UB) was used as variable selection. Nine wavelengths were selected. Various chemometric analysis methods including linear PLSR and multiple linear regression and nonlinear LS-SVM and back-propagation artificial neural network (BP-ANN) were compared. The simplified models showed better capability than those were built based on the whole dataset in prediction of TBARS values. Moreover, the nonlinear models were preferred over linear models. Among the four chemometric algorithms, the best and weakest models were LS-SVM and PLSR model, respectively. UB-LS-SVM model was the optimal models for predicting TBARS value in rainbow trout fillets ( R P 2 = 0.831; RMSEP = 0.125 mg MDA/kg). The establishing of lipid-oxidation prediction model in rainbow trout fish was complicated, due to the fluctuations of TBARS values during storage. Therefore, further researches are needed to improve the prediction results and applicability of HIS technique for prediction of TBARS value in rainbow trout fish.
Collapse
Affiliation(s)
- Sara Khoshnoudi‐Nia
- Seafood Processing Research Group & Department of Food Science and Technology, School of AgricultureShiraz UniversityShirazIran
| | - Marzieh Moosavi‐Nasab
- Seafood Processing Research Group & Department of Food Science and Technology, School of AgricultureShiraz UniversityShirazIran
| |
Collapse
|
13
|
Salta Z, Kosmas AM, Ventura ON, Barone V. Computational Evidence Suggests That 1-Chloroethanol May Be an Intermediate in the Thermal Decomposition of 2-Chloroethanol into Acetaldehyde and HCl. J Phys Chem A 2019; 123:1983-1998. [PMID: 30794424 DOI: 10.1021/acs.jpca.8b11966] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The dehalogenation of 2-chloroethanol (2ClEtOH) in the gas phase with and without the participation of catalytic water molecules has been investigated using methods rooted into the density functional theory. The well-known HCl elimination leading to vinyl alcohol (VA) was compared to the alternative elimination route toward oxirane and shown to be kinetically and thermodynamically more favorable. However, the isomerization of VA to acetaldehyde in the gas phase, in the absence of water, was shown to be kinetically and thermodynamically less favorable than the recombination of VA and HCl to form the isomeric 1-chloroethanol (1ClEtOH) species. At the ωB97X-D/cc-pVTZ level of calculation, this species is more stable than 2ClEtOH by about 6 kcal mol-1 at 298 K, and the reaction barrier for VA to 1ClEtOH is 23 kcal mol-1 versus 55 kcal mol-1 for the direct transformation of VA to acetaldehyde. In a successive step, 1ClEtOH can decompose directly to acetaldehyde and HCl with a lower barrier (29 kcal mol-1) than that of VA to the same products (55 kcal mol-1). The calculations were repeated using a single ancillary water molecule (W) in the complexes 2ClEtOH_W and 1ClEtOH_W. The latter adduct is now more stable than 2ClEtOH_W by about 8 kcal mol-1 at 298 K, implying that the water molecule increased the already higher stability of 1ClEtOH in the gas phase. However, this catalytic water molecule lowers dramatically the barrier for the interconversion of VA to acetaldehyde (from 55 to 7 kcal mol-1). This barrier is now smaller than the one for the conversion to 1ClEtOH (which also decreases, but not so much, from 23 to 13 kcal mol-1). Thus, it is concluded that while 1ClEtOH may be a plausible intermediate in the gas phase dehalogenation of 2ClEtOH, it is unlikely that it plays a major role in water complexes (or, by inference, aqueous solution). It is also shown that neither in the gas phase nor in the cluster with one water molecule, the oxirane path is more favorable than the VA alcohol path. Additionally, a direct conversion of 2ClEtOH to 1ClEtOH through a transition state which resembles a VA molecule in a complex with a chlorine atom and a hydrogen atom on both sides of this planar species was found. This reaction path has also lower activation energy than the conversion to oxirane but not as low as the conversion to VA.
Collapse
Affiliation(s)
- Zoi Salta
- SMART Lab , Scuola Normale Superiore di Pisa , Piazza dei Cavalieri, 7 , 56126 Pisa , Italy
| | - Agnie M Kosmas
- Physical Chemistry Sector, Department of Chemistry , University of Ioannina , PC 45110 Ioannina , Greece
| | - Oscar N Ventura
- Computational Chemistry and Biology Group, CCBG, DETEMA, Facultad de Química , Universidad de la Republica (Udelar) , Montevideo 11400 , Uruguay
| | - Vincenzo Barone
- SMART Lab , Scuola Normale Superiore di Pisa , Piazza dei Cavalieri, 7 , 56126 Pisa , Italy
| |
Collapse
|
14
|
Can Combined Electrostatic and Polarization Effects Alone Explain the F···F Negative-Negative Bonding in Simple Fluoro-Substituted Benzene Derivatives? A First-Principles Perspective. COMPUTATION 2018. [DOI: 10.3390/computation6040051] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The divergence of fluorine-based systems and significance of their nascent non-covalent chemistry in molecular assemblies are presented in a brief review of the field. Emphasis has been placed to show that type-I and -II halogen-centered F···F long-ranged intermolecular distances viable between the entirely negative fluorine atoms in some fluoro-substituted dimers of C6H6 can be regarded as the consequence of significant non-covalent attractive interactions. Such attractive interactions observed in the solid-state structures of C6F6 and other similar fluorine-substituted aromatic compounds have frequently been underappreciated. While these are often ascribed to crystal packing effects, we show using first-principles level calculations that these are much more fundamental in nature. The stability and reliability of these interactions are supported by their negative binding energies that emerge from a supermolecular procedure using MP2 (second-order Møller-Plesset perturbation theory), and from the Symmetry Adapted Perturbation Theory, in which the latter does not determine the interaction energy by computing the total energy of the monomers or dimer. Quantum Theory of Atoms in Molecules and Reduced Density Gradient Non-Covalent Index charge-density-based approaches confirm the F···F contacts are a consequence of attraction by their unified bond path (and bond critical point) and isosurface charge density topologies, respectively. These interactions can be explained neither by the so-called molecular electrostatic surface potential (MESP) model approach that often demonstrates attraction between sites of opposite electrostatic surface potential by means of Coulomb’s law of electrostatics, nor purely by the effect of electrostatic polarization. We provide evidence against the standalone use of this approach and the overlooking of other approaches, as the former does not allow for the calculation of the electrostatic potential on the surfaces of the overlapping atoms on the monomers as in the equilibrium geometry of a complex. This study thus provides unequivocal evidence of the limitation of the MESP approach for its use in gaining insight into the nature of reactivity of overlapped interacting atoms and the intermolecular interactions involved.
Collapse
|
15
|
DeJaco RF, Elyassi B, Dorneles de Mello M, Mittal N, Tsapatsis M, Siepmann JI. Understanding the unique sorption of alkane-α, ω-diols in silicalite-1. J Chem Phys 2018; 149:072331. [DOI: 10.1063/1.5026937] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Robert F. DeJaco
- Department of Chemical Engineering and Materials Science, University of Minnesota, 412 Washington Avenue SE, Minneapolis, Minnesota 55455-0132, USA
- Department of Chemistry and Chemical Theory Center, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455-0431, USA
| | - Bahman Elyassi
- Department of Chemical Engineering and Materials Science, University of Minnesota, 412 Washington Avenue SE, Minneapolis, Minnesota 55455-0132, USA
| | - Matheus Dorneles de Mello
- Department of Chemical Engineering and Materials Science, University of Minnesota, 412 Washington Avenue SE, Minneapolis, Minnesota 55455-0132, USA
| | - Nitish Mittal
- Department of Chemical Engineering and Materials Science, University of Minnesota, 412 Washington Avenue SE, Minneapolis, Minnesota 55455-0132, USA
| | - Michael Tsapatsis
- Department of Chemical Engineering and Materials Science, University of Minnesota, 412 Washington Avenue SE, Minneapolis, Minnesota 55455-0132, USA
| | - J. Ilja Siepmann
- Department of Chemical Engineering and Materials Science, University of Minnesota, 412 Washington Avenue SE, Minneapolis, Minnesota 55455-0132, USA
- Department of Chemistry and Chemical Theory Center, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455-0431, USA
| |
Collapse
|
16
|
Futami Y, Minamoto C, Kudoh S. Anharmonic calculations of frequencies and intensities of OH stretching vibrations of (R)-1,3-butanediol conformers in the fundamentals and first overtones by density functional theory. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2018; 197:251-254. [PMID: 29501370 DOI: 10.1016/j.saa.2018.02.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 02/05/2018] [Accepted: 02/07/2018] [Indexed: 06/08/2023]
Abstract
The frequencies and absorption intensities of the five kinds of conformers of 1,3-butanediol with the same carbon skeleton (GG') were calculated by anharmonic calculation for the fundamentals and first overtones of OH stretching vibrations. The four kinds of conformers form intramolecular hydrogen bonds and one conformer did not. Intramolecular hydrogen bond formation shifted the frequency of fundamental and first overtone of H-bonding OH stretching vibration to the lower frequency. The absorption intensities of the fundamentals as well as the vibrational anharmonicities increased upon hydrogen bond formation, while the intensities of first overtones decreased. The differences of conformers were clearly seen in the frequencies of the first overtones of free OH.
Collapse
Affiliation(s)
- Yoshisuke Futami
- Department of Biological and Chemical Systems Engineering, National Institute of Technology, Kumamoto College, Yatsushiro, Kumamoto 866-8501, Japan.
| | - Chihiro Minamoto
- Department of Applied Chemistry and Biotechnology, National Institute of Technology, Niihama College, Niihama, Ehime 792-8580, Japan
| | - Satoshi Kudoh
- College of Engineering, Shibaura Institute of Technology, Saitama, Saitama 337-8570, Japan
| |
Collapse
|
17
|
Classification and Discrimination of Different Fungal Diseases of Three Infection Levels on Peaches Using Hyperspectral Reflectance Imaging Analysis. SENSORS 2018; 18:s18041295. [PMID: 29690625 PMCID: PMC5948498 DOI: 10.3390/s18041295] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 04/08/2018] [Accepted: 04/12/2018] [Indexed: 11/16/2022]
Abstract
Peaches are susceptible to infection from several postharvest diseases. In order to control disease and avoid potential health risks, it is important to identify suitable treatments for each disease type. In this study, the spectral and imaging information from hyperspectral reflectance (400~1000 nm) was used to evaluate and classify three kinds of common peach disease. To reduce the large dimensionality of the hyperspectral imaging, principal component analysis (PCA) was applied to analyse each wavelength image as a whole, and the first principal component was selected to extract the imaging features. A total of 54 parameters were extracted as imaging features for one sample. Three decayed stages (slight, moderate and severe decayed peaches) were considered for classification by deep belief network (DBN) and partial least squares discriminant analysis (PLSDA) in this study. The results showed that the DBN model has better classification results than the classification accuracy of the PLSDA model. The DBN model based on integrated information (494 features) showed the highest classification results for the three diseases, with accuracies of 82.5%, 92.5%, and 100% for slightly-decayed, moderately-decayed and severely-decayed samples, respectively. The successive projections algorithm (SPA) was used to select the optimal features from the integrated information; then, six optimal features were selected from a total of 494 features to establish the simple model. The SPA-PLSDA model showed better results which were more feasible for industrial application. The results showed that the hyperspectral reflectance imaging technique is feasible for detecting different kinds of diseased peaches, especially at the moderately- and severely-decayed levels.
Collapse
|
18
|
Kwak J, Nam SS, Cho J, Sim E, Lee SY. Interior-filled self-assemblies of tyrosyl bolaamphiphiles regulated by hydrogen bonds. Phys Chem Chem Phys 2018; 19:10274-10281. [PMID: 28379263 DOI: 10.1039/c6cp08863e] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Bolaamphiphilic molecules with tyrosyl end groups formed interior-filled spherical self-assemblies, which are distinct from the vesicular or tubular structures of other similar peptidic bolaamphiphile assemblies reported in the literature. In this study, the self-assembly mechanism of these tyrosyl bolaamphiphiles was investigated taking into consideration the solvent effects on the molecular interaction forces using molecular modeling. The dissipative particle dynamics simulation of an aqueous tyrosyl bolaamphiphile solution suggested that the interior-filled assemblies were produced by a solvent-regulated assembly of small aggregates of bolaamphiphiles. These small aggregates were generated by hydrophobic interactions at an early stage, and then further assembled to form large spherical assemblies through intermolecular forces, including hydrogen bonds between the intermediate aggregates. Additional experiments and density functional theory calculations based on solvent variations proved that smaller assembled structures could be obtained by disrupting the hydrogen bonds between the intermediates. The assembly mechanism of these peptidic bolaamphiphiles afforded a facile way to create condensed supramolecular structures with controlled sizes.
Collapse
Affiliation(s)
- Jinyoung Kwak
- Department of Chemical and Biomolecular Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea.
| | | | | | | | | |
Collapse
|
19
|
Pan Y, Sun DW, Cheng JH, Han Z. Non-destructive Detection and Screening of Non-uniformity in Microwave Sterilization Using Hyperspectral Imaging Analysis. FOOD ANAL METHOD 2018. [DOI: 10.1007/s12161-017-1134-5] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
20
|
Zhu T, de Silva P, Van Voorhis T. Self-Attractive Hartree Decomposition: Partitioning Electron Density into Smooth Localized Fragments. J Chem Theory Comput 2017; 14:92-103. [DOI: 10.1021/acs.jctc.7b00931] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Tianyu Zhu
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Piotr de Silva
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Troy Van Voorhis
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| |
Collapse
|
21
|
Nondestructive Freshness Discriminating of Shrimp Using Visible/Near-Infrared Hyperspectral Imaging Technique and Deep Learning Algorithm. FOOD ANAL METHOD 2017. [DOI: 10.1007/s12161-017-1050-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
22
|
Intramolecular hydrogen-bonding effects on O H stretch overtone excitation for fluorinated hydroperoxides. Chem Phys 2017. [DOI: 10.1016/j.chemphys.2017.03.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|
23
|
Athokpam B, Ramesh SG, McKenzie RH. Effect of hydrogen bonding on the infrared absorption intensity of OH stretch vibrations. Chem Phys 2017. [DOI: 10.1016/j.chemphys.2017.03.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|
24
|
Hyperspectral reflectance imaging combined with chemometrics and successive projections algorithm for chilling injury classification in peaches. Lebensm Wiss Technol 2017. [DOI: 10.1016/j.lwt.2016.10.006] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
25
|
Yang Q, Sun DW, Cheng W. Development of simplified models for nondestructive hyperspectral imaging monitoring of TVB-N contents in cured meat during drying process. J FOOD ENG 2017. [DOI: 10.1016/j.jfoodeng.2016.07.015] [Citation(s) in RCA: 120] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
26
|
Mackeprang K, Xu ZH, Maroun Z, Meuwly M, Kjaergaard HG. Spectroscopy and dynamics of double proton transfer in formic acid dimer. Phys Chem Chem Phys 2016; 18:24654-62. [PMID: 27545453 DOI: 10.1039/c6cp03462d] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
We present the isolated gas phase infrared spectra of formic acid dimer, (HCOOH)2, and its deuterated counterpart formic-d acid, (DCOOH)2, at room temperature. The formic acid dimer spectrum was obtained by spectral subtraction of a spectrum of formic acid vapor recorded at low pressure from that recorded at a higher pressure. The spectra of formic acid vapor contain features from both formic acid monomer and formic acid dimer, but at low and high pressures of formic acid, the equilibrium is pushed towards the monomer and dimer, respectively. A similar approach was used for the formic-d acid dimer. Building on the previous development of the Molecular Mechanics with Proton Transfer (MMPT) force field for simulating proton transfer reactions, molecular dynamics (MD) simulations were carried out to interpret the experimental spectra in the OH-stretching region. Within the framework of MMPT, a combination of symmetric single and double minimum potential energy surfaces (PESs) provides a good description of the double proton transfer PES. In a next step, potential morphing together with electronic structure calculations at the B3LYP and MP2 level of theory was used to align the computed and experimentally observed spectral features in the OH-stretching region. From this analysis, a barrier for double proton transfer between 5 and 7 kcal mol(-1) was derived, which compares with a CCSD(T)/aug-cc-pVTZ calculated barrier of 7.9 kcal mol(-1). Such a combination of experimental and computational techniques for estimating barriers for proton transfer in gas phase systems is generic and holds promise for further improved PESs and energetics of these important systems. Additional MD simulations at the semi-empirical DFTB level of theory agree quite well for the center band position but underestimate the width of the OH-stretching band.
Collapse
Affiliation(s)
- Kasper Mackeprang
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark.
| | | | | | | | | |
Collapse
|
27
|
Futami Y, Ozaki Y, Ozaki Y. Absorption intensity changes and frequency shifts of fundamental and first overtone bands for OH stretching vibration of methanol upon methanol–pyridine complex formation in CCl4: analysis by NIR/IR spectroscopy and DFT calculations. Phys Chem Chem Phys 2016; 18:5580-6. [DOI: 10.1039/c5cp07027a] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The first overtone of the OH stretching mode of the OH–N hydrogen bond of the methanol–pyridine complex was observed.
Collapse
Affiliation(s)
- Yoshisuke Futami
- Department of Biological and Chemical Systems Engineering
- National Institute of Technology
- Kumamoto College
- Yatsushiro
- Japan
| | - Yasushi Ozaki
- Department of Chemistry
- Faculty of Science
- Josai University
- Sakado
- Japan
| | - Yukihiro Ozaki
- Department of Chemistry
- School of Science and Technology
- KwanseiGakuin University
- Sanda
- Japan
| |
Collapse
|
28
|
Sun Y, Gu X, Wang Z, Huang Y, Wei Y, Zhang M, Tu K, Pan L. Growth Simulation and Discrimination of Botrytis cinerea, Rhizopus stolonifer and Colletotrichum acutatum Using Hyperspectral Reflectance Imaging. PLoS One 2015; 10:e0143400. [PMID: 26642054 PMCID: PMC4671615 DOI: 10.1371/journal.pone.0143400] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 11/04/2015] [Indexed: 11/18/2022] Open
Abstract
This research aimed to develop a rapid and nondestructive method to model the growth and discrimination of spoilage fungi, like Botrytis cinerea, Rhizopus stolonifer and Colletotrichum acutatum, based on hyperspectral imaging system (HIS). A hyperspectral imaging system was used to measure the spectral response of fungi inoculated on potato dextrose agar plates and stored at 28°C and 85% RH. The fungi were analyzed every 12 h over two days during growth, and optimal simulation models were built based on HIS parameters. The results showed that the coefficients of determination (R2) of simulation models for testing datasets were 0.7223 to 0.9914, and the sum square error (SSE) and root mean square error (RMSE) were in a range of 2.03–53.40×10−4 and 0.011–0.756, respectively. The correlation coefficients between the HIS parameters and colony forming units of fungi were high from 0.887 to 0.957. In addition, fungi species was discriminated by partial least squares discrimination analysis (PLSDA), with the classification accuracy of 97.5% for the test dataset at 36 h. The application of this method in real food has been addressed through the analysis of Botrytis cinerea, Rhizopus stolonifer and Colletotrichum acutatum inoculated in peaches, demonstrating that the HIS technique was effective for simulation of fungal infection in real food. This paper supplied a new technique and useful information for further study into modeling the growth of fungi and detecting fruit spoilage caused by fungi based on HIS.
Collapse
Affiliation(s)
- Ye Sun
- College of Food Science and Technology, Nanjing Agricultural University, No.1, Weigang Road, Nanjing, Jiangsu, 210095, China
| | - Xinzhe Gu
- College of Food Science and Technology, Nanjing Agricultural University, No.1, Weigang Road, Nanjing, Jiangsu, 210095, China
| | - Zhenjie Wang
- College of Food Science and Technology, Nanjing Agricultural University, No.1, Weigang Road, Nanjing, Jiangsu, 210095, China
| | - Yangmin Huang
- College of Food Science and Technology, Nanjing Agricultural University, No.1, Weigang Road, Nanjing, Jiangsu, 210095, China
| | - Yingying Wei
- College of Food Science and Technology, Nanjing Agricultural University, No.1, Weigang Road, Nanjing, Jiangsu, 210095, China
| | - Miaomiao Zhang
- College of Food Science and Technology, Nanjing Agricultural University, No.1, Weigang Road, Nanjing, Jiangsu, 210095, China
| | - Kang Tu
- College of Food Science and Technology, Nanjing Agricultural University, No.1, Weigang Road, Nanjing, Jiangsu, 210095, China
| | - Leiqing Pan
- College of Food Science and Technology, Nanjing Agricultural University, No.1, Weigang Road, Nanjing, Jiangsu, 210095, China
- * E-mail:
| |
Collapse
|
29
|
Varadwaj PR, Varadwaj A, Jin BY. Hexahalogenated and their mixed benzene derivatives as prototypes for the understanding of halogen···halogen intramolecular interactions: New insights from combined DFT, QTAIM-, and RDG-based NCI analyses. J Comput Chem 2015; 36:2328-43. [DOI: 10.1002/jcc.24211] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Revised: 08/28/2015] [Accepted: 08/31/2015] [Indexed: 01/21/2023]
Affiliation(s)
| | - Arpita Varadwaj
- Department of Chemistry; National Taiwan University; Taipei 10617 Taiwan
| | - Bih-Yaw Jin
- Department of Chemistry; National Taiwan University; Taipei 10617 Taiwan
| |
Collapse
|
30
|
Asari AH, Lam YH, Tius MA, Houk KN. Origins of the Stereoselectivity in a Thiourea–Primary Amine-Catalyzed Nazarov Cyclization. J Am Chem Soc 2015; 137:13191-9. [DOI: 10.1021/jacs.5b08969] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Austin H. Asari
- Department
of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, United States
| | - Yu-hong Lam
- Department
of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, United States
| | - Marcus A. Tius
- Department
of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii 96822, United States
- The Cancer Research Center of Hawaii, Honolulu, Hawaii 96813, United States
| | - K. N. Houk
- Department
of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, United States
| |
Collapse
|
31
|
Czarnecki MA, Morisawa Y, Futami Y, Ozaki Y. Advances in Molecular Structure and Interaction Studies Using Near-Infrared Spectroscopy. Chem Rev 2015; 115:9707-44. [DOI: 10.1021/cr500013u] [Citation(s) in RCA: 146] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | - Yusuke Morisawa
- Department
of Chemistry, School of Science and Engineering, Kinki University, Higashi-Osaka, Osaka 577-8502, Japan
| | - Yoshisuke Futami
- Department
of Biological and Chemical Systems Engineering, National Institute of Technology, Kumamoto College, Yatsushiro, Kumamoto 866-8501, Japan
| | - Yukihiro Ozaki
- Department
of Chemistry, School of Science and Technology, Kwansei Gakuin University, Sanda, Hyogo 669-1337, Japan
| |
Collapse
|
32
|
Schrøder SD, Wallberg JH, Kroll JA, Maroun Z, Vaida V, Kjaergaard HG. Intramolecular Hydrogen Bonding in Methyl Lactate. J Phys Chem A 2015; 119:9692-702. [DOI: 10.1021/acs.jpca.5b04812] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Sidsel D. Schrøder
- Department
of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark
| | - Jens H. Wallberg
- Department
of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark
| | - Jay A. Kroll
- Department
of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, United States
- Cooperative Institute for Research in Environmental Sciences, Boulder, Colorado 80309, United States
| | - Zeina Maroun
- Department
of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark
| | - Veronica Vaida
- Department
of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, United States
- Cooperative Institute for Research in Environmental Sciences, Boulder, Colorado 80309, United States
| | - Henrik G. Kjaergaard
- Department
of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark
| |
Collapse
|
33
|
Howard DL, Kjaergaard HG, Huang J, Meuwly M. Infrared and Near-Infrared Spectroscopy of Acetylacetone and Hexafluoroacetylacetone. J Phys Chem A 2015; 119:7980-90. [DOI: 10.1021/acs.jpca.5b01863] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Daryl L. Howard
- Australian Synchrotron, 800 Blackburn
Road, Clayton, Victoria 3168, Australia
- Department
of Chemistry, University of Otago, P.O. Box 56, Dunedin 9016, New Zealand
| | - Henrik G. Kjaergaard
- Department
of Chemistry, University of Otago, P.O. Box 56, Dunedin 9016, New Zealand
- Department
of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark
| | - Jing Huang
- Department
of Pharmaceutical Science, University of Maryland, Baltimore, Maryland 21201, United States
- Department
of Chemistry, University of Basel, Klingelbergstrasse 80, 4056 Basel, Switzerland
| | - Markus Meuwly
- Department
of Chemistry, University of Basel, Klingelbergstrasse 80, 4056 Basel, Switzerland
- Department
of Chemistry, Brown University, Providence, Rhode Island 01912, United States
| |
Collapse
|
34
|
Das P, Das PK, Arunan E. Conformational stability and intramolecular hydrogen bonding in 1,2-ethanediol and 1,4-butanediol. J Phys Chem A 2015; 119:3710-20. [PMID: 25839224 DOI: 10.1021/jp512686s] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The gas-phase infrared spectra of 1,2-ED and 1,4-BD have been recorded at three different temperatures using a multipass gas cell of 6 m optical path length. DFT calculation has also been carried out using 6-311++G** and aug-cc-pVDZ basis sets to look for the existence of intramolecular hydrogen bonding in them from the red shift and infrared absorption intensity enhancement of the bonded O-H band compared to that of the free O-H band. Equilibrium population analysis with 10 conformers of 1,2-ED and 1,4-BD at experimental temperatures were carried out for the reconstruction of the observed vibrational spectra at that temperature using standard statistical relationships. The most abundant conformer at experimental temperatures was identified. In 1,2-ED a red shift of 45 cm(-1) in the intramolecularly interacting O-H stretching vibrational band position and no significant intensity enhancement compared to that of the free O-H have been observed. On the contrary, in one of the hydrogen-bonded conformers of 1,4-BD, a 124 cm(-1) red shift in the O-H stretching frequency and a 8.5 times intensity enhancement for the "bonded" O-H compared to that of the "free" O-H is seen. On the basis of this comparative study, we have concluded that strong intramolecular hydrogen bonding exists in 1,4-BD. But there appears to be weak intramolecular hydrogen bonding in 1,2-ED at temperatures of 303, 313, and 323 K in the gas phase. We have found that most stable hydrogen-bonded conformers of 1,4-BD are less populated than some of the non-hydrogen-bonded conformers. Even for the 1,4-BD, the relative population of the g'GG'Gt conformer, which has a strong intramolecular hydrogen bond, is less than what is predicted. Perhaps the intramolecular hydrogen bond plays a less significant role in the relative stability of the various conformers than what has been predicted from calculations and prevails in the literature.
Collapse
Affiliation(s)
- Prasanta Das
- Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560012, India
| | - Puspendu K Das
- Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560012, India
| | - E Arunan
- Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560012, India
| |
Collapse
|
35
|
Cheng JH, Sun DW, Pu H, Zhu Z. Development of hyperspectral imaging coupled with chemometric analysis to monitor K value for evaluation of chemical spoilage in fish fillets. Food Chem 2015; 185:245-53. [PMID: 25952865 DOI: 10.1016/j.foodchem.2015.03.111] [Citation(s) in RCA: 94] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Revised: 03/12/2015] [Accepted: 03/27/2015] [Indexed: 11/28/2022]
Abstract
K value is an important freshness index widely used for indication of nucleotide degradation and assessment of chemical spoilage. The feasibility of hyperspectral imaging (400-1000 nm) for determination of K value in grass carp and silver carp fillets was investigated. Partial least square (PLS) regression and least square support vector machines (LS-SVM) models established using full wavelengths showed excellent performances and the PLS model was better with higher determination coefficients of prediction (R(2)P = 0.936) and lower root mean square errors of prediction (RMSEP = 5.21%). The simplified PLS and LS-SVM models using the seven optimal wavelengths selected by successive projections algorithm (SPA) also presented good performances. The spatial distribution map of K value was generated by transferring the SPA-PLS model to each pixel of the images. The current study showed the suitability of using hyperspectral imaging to determine K value for evaluation of chemical spoilage and freshness of fish fillets.
Collapse
Affiliation(s)
- Jun-Hu Cheng
- College of Light Industry and Food Sciences, South China University of Technology, Guangzhou 510641, China
| | - Da-Wen Sun
- College of Light Industry and Food Sciences, South China University of Technology, Guangzhou 510641, China; Food Refrigeration and Computerized Food Technology, Agriculture and Food Science Centre, University College Dublin, National University of Ireland, Belfield, Dublin 4, Ireland.
| | - Hongbin Pu
- College of Light Industry and Food Sciences, South China University of Technology, Guangzhou 510641, China
| | - Zhiwei Zhu
- College of Light Industry and Food Sciences, South China University of Technology, Guangzhou 510641, China
| |
Collapse
|
36
|
Tan NY, Li R, Bräuer P, D'Agostino C, Gladden LF, Zeitler JA. Probing hydrogen-bonding in binary liquid mixtures with terahertz time-domain spectroscopy: a comparison of Debye and absorption analysis. Phys Chem Chem Phys 2015; 17:5999-6008. [DOI: 10.1039/c4cp04477k] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Terahertz time-domain spectroscopy is used to explore hydrogen bonding structure and dynamics in binary liquid mixtures, spanning a range of protic–protic, protic–aprotic and aprotic–aprotic systems.
Collapse
Affiliation(s)
- Nicholas Y. Tan
- Department of Chemical Engineering and Biotechnology
- University of Cambridge
- Cambridge CB2 3RA
- UK
| | - Ruoyu Li
- Department of Chemical Engineering and Biotechnology
- University of Cambridge
- Cambridge CB2 3RA
- UK
| | - Pierre Bräuer
- Department of Chemical Engineering and Biotechnology
- University of Cambridge
- Cambridge CB2 3RA
- UK
| | - Carmine D'Agostino
- Department of Chemical Engineering and Biotechnology
- University of Cambridge
- Cambridge CB2 3RA
- UK
| | - Lynn F. Gladden
- Department of Chemical Engineering and Biotechnology
- University of Cambridge
- Cambridge CB2 3RA
- UK
| | - J. Axel Zeitler
- Department of Chemical Engineering and Biotechnology
- University of Cambridge
- Cambridge CB2 3RA
- UK
| |
Collapse
|
37
|
Arunan E, Mani D. Dynamics of the chemical bond: inter- and intra-molecular hydrogen bond. Faraday Discuss 2015; 177:51-64. [DOI: 10.1039/c4fd00167b] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this discussion, we show that a static definition of a ‘bond’ is not viable by looking at a few examples for both inter- and intra-molecular hydrogen bonding. This follows from our earlier work (Goswami and Arunan,Phys. Chem. Chem. Phys.2009,11, 8974) which showed a practical way to differentiate ‘hydrogen bonding’ from ‘van der Waals interaction’. We report results fromab initioand atoms in molecules theoretical calculations for a series of Rg⋯HX complexes (Rg = He/Ne/Ar and X = F/Cl/Br) and ethane-1,2-diol. Results for the Rg⋯HX/DX complexes show that Rg⋯DX could have a ‘deuterium bond’ even when Rg⋯HX is not ‘hydrogen bonded’, according to the practical criterion given by Goswami and Arunan. Results for ethane-1,2-diol show that an ‘intra-molecular hydrogen bond’ can appear during a normal mode vibration which is dominated by the O⋯O stretching, though a ‘bond’ is not found in the equilibrium structure. This dynamical ‘bond’ formation may nevertheless be important in ensuring the continuity of electron density across a molecule. In the former case, a vibration ‘breaks’ an existing bond and in the later case, a vibration leads to ‘bond’ formation. In both cases, the molecule/complex stays bound irrespective of what happens to this ‘hydrogen bond’. Both these cases push the borders on the recent IUPAC recommendation on hydrogen bonding (Arunanet al. Pure. Appl. Chem.2011,831637) and justify the inclusive nature of the definition.
Collapse
Affiliation(s)
- Elangannan Arunan
- Department of Inorganic and Physical Chemistry
- Indian Institute of Science
- Bangalore
- India 560012
| | - Devendra Mani
- Department of Inorganic and Physical Chemistry
- Indian Institute of Science
- Bangalore
- India 560012
- Department of Physical Chemistry II
| |
Collapse
|
38
|
Chen Y, Ozaki Y, Czarnecki MA. Molecular structure and hydrogen bonding in pure liquid ethylene glycol and ethylene glycol-water mixtures studied using NIR spectroscopy. Phys Chem Chem Phys 2014; 15:18694-701. [PMID: 24071663 DOI: 10.1039/c3cp52146j] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The molecular structure and hydrogen bonding of ethylene glycol (EG) and EG-water mixtures in the liquid phase were studied by using near-infrared (NIR) spectroscopy. The spectra were evaluated using a two-dimensional (2D) correlation approach, moving-window 2D correlation analysis and chemometric methods. The minor changes for the CH stretching bands indicate that the structures of pure liquid EG and EG-water mixtures are determined by the intermolecular hydrogen bonding through the OH groups. The analysis of the ν2 + ν3 combination band of water reveals that in EG-rich solutions the molecules of water are predominantly bonded with two molecules of EG and this cooperative hydrogen bonding is stronger than that in bulk water. Further increase in the water content leads to formation of small water clusters around OH groups of EG. Comparing results for the binary mixtures of water with different organic solvents one can conclude that the total amount and distribution of the polar groups are the most important factors determining the solubility of water in the organic phase. The distribution of these groups depends on the length and structure of the hydrocarbon chain. Due to high population and relatively uniform distribution of the OH groups of EG water has unlimited solubility in liquid EG.
Collapse
Affiliation(s)
- Yujing Chen
- School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640, China
| | | | | |
Collapse
|
39
|
Chen Y, Morisawa Y, Futami Y, Czarnecki MA, Wang HS, Ozaki Y. Combined IR/NIR and density functional theory calculations analysis of the solvent effects on frequencies and intensities of the fundamental and overtones of the C ═ O stretching vibrations of acetone and 2-hexanone. J Phys Chem A 2014; 118:2576-83. [PMID: 24654701 DOI: 10.1021/jp411855b] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Vibrational overtone studies primarily focus on X-H stretching overtone transitions, where X is an atom like C, O, N, or S. In contrast, the studies on the C ═ O stretching overtones are very scattered. To advance the research in this field, we measured the fundamental, first, and second overtones of the C ═ O stretching vibration of acetone and 2-hexanone in n-hexane, CCl4, and CHCl3, as well as in the vapor phase using FT-IR/FT-NIR spectroscopy. Density functional theory (DFT) calculations have also been performed to help the assignment of the C ═ O stretching bands and to guide interpretation of the experimental results. It was found that the wavenumbers, absorption intensities, and oscillator strengths of the C ═ O stretching bands show marked solvent dependence. In the fundamental and the first overtone regions, the intensities of the C ═ O stretching vibration were found to be pronouncedly more intense than those of the C-H stretching vibration. In the second overtone region, the intensities of the C-H stretching vibration are comparable to those of the C ═ O stretching vibration. The theoretical and observed decrease in integrated intensity upon going from the fundamental to the first overtone of the C ═ O stretching vibration is around 50, which is significantly larger than those of the O-H, C-H, and S-H stretching vibration. Both the calculated and experimental results suggest that excessive weakness in the C ═ O stretching overtone was shown to be a result of both a low anharmonicity and a substantial reduction in the oscillator strength. These results provide new insight into our understanding of the C ═ O stretching vibration.
Collapse
Affiliation(s)
- Yujing Chen
- School of Chemistry and Chemical Engineering, South China University of Technology , Guangzhou 510640, China
| | | | | | | | | | | |
Collapse
|
40
|
Cheng JH, Sun DW, Zeng XA, Pu HB. Non-destructive and rapid determination of TVB-N content for freshness evaluation of grass carp (Ctenopharyngodon idella) by hyperspectral imaging. INNOV FOOD SCI EMERG 2014. [DOI: 10.1016/j.ifset.2013.10.013] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
|
41
|
Kollipost F, Papendorf K, Lee YF, Lee YP, Suhm MA. Alcohol dimers – how much diagonal OH anharmonicity? Phys Chem Chem Phys 2014; 16:15948-56. [DOI: 10.1039/c4cp01418a] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The massive infrared attenuation and increased anharmonicity of OH stretching overtones in alcohol dimers is experimentally quantified.
Collapse
Affiliation(s)
- Franz Kollipost
- Georg-August-Universität Göttingen
- Institut für Physikalische Chemie
- 37077 Göttingen, Germany
| | - Kim Papendorf
- Georg-August-Universität Göttingen
- Institut für Physikalische Chemie
- 37077 Göttingen, Germany
| | - Yu-Fang Lee
- Department of Applied Chemistry and Institute of Molecular Science
- National Chiao Tung University
- Hsinchu 30010, Taiwan
| | - Yuan-Pern Lee
- Department of Applied Chemistry and Institute of Molecular Science
- National Chiao Tung University
- Hsinchu 30010, Taiwan
- Institute of Atomic and Molecular Sciences
- Academia Sinica
| | - Martin A. Suhm
- Georg-August-Universität Göttingen
- Institut für Physikalische Chemie
- 37077 Göttingen, Germany
| |
Collapse
|
42
|
Thomsen DL, Axson JL, Schrøder SD, Lane JR, Vaida V, Kjaergaard HG. Intramolecular Interactions in 2-Aminoethanol and 3-Aminopropanol. J Phys Chem A 2013; 117:10260-73. [DOI: 10.1021/jp405512y] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ditte L. Thomsen
- Department
of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark
| | - Jessica L. Axson
- Department
of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, United States
- Cooperative Institute for Research in Environmental Sciences, Boulder, Colorado 80309, United States
| | - Sidsel D. Schrøder
- Department
of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark
| | - Joseph R. Lane
- Department
of Chemistry, University of Waikato, Private Bag 3105, Hamilton 3240, New Zealand
| | - Veronica Vaida
- Department
of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, United States
- Cooperative Institute for Research in Environmental Sciences, Boulder, Colorado 80309, United States
| | - Henrik G. Kjaergaard
- Department
of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark
| |
Collapse
|
43
|
Jesus AJL, Rosado MTS, Reva I, Fausto R, Eusébio MES, Redinha JS. Structure of isolated 1,4-butanediol: combination of MP2 calculations, NBO analysis, and matrix-isolation infrared spectroscopy. J Phys Chem A 2013; 112:4669-78. [PMID: 18444635 DOI: 10.1021/jp7116196] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Theoretical calculations at the MP2 level, NBO and AIM analysis, and matrix-isolation infrared spectroscopy have been used to investigate the structure of the isolated molecule of 1,4-butanediol (1,4-BDO). Sixty-five structures were found to be minima on the potential energy surface, and the three most stable forms are characterized by a folded backbone conformation leading to the formation of an intramolecular H-bond. To better characterize the intramolecular interactions and particularly the hydrogen bonds, natural bond orbital analysis (NBO) was performed for the four most stable conformers, and was further complemented with an atoms-in-molecules (AIM) topological analysis. Infrared spectra of 1,4-BDO isolated in low-temperature argon and xenon matrixes show a good agreement with a population-weighted mean theoretical spectrum, and the spectral features of the conformers expected to be trapped in the matrixes were observed experimentally. Annealing the xenon matrix from 20 to 60 K resulted in significant spectral changes, which were interpreted based on the barriers to intramolecular rotation. An estimation of the intramolecular hydrogen bond energy was carried out following three different methodologies.
Collapse
Affiliation(s)
- A J Lopes Jesus
- Faculty of Pharmacy, University of Coimbra, 3004-295, Coimbra, Portugal.
| | | | | | | | | | | |
Collapse
|
44
|
Lane JR, Contreras-García J, Piquemal JP, Miller BJ, Kjaergaard HG. Are Bond Critical Points Really Critical for Hydrogen Bonding? J Chem Theory Comput 2013; 9:3263-6. [PMID: 26584086 DOI: 10.1021/ct400420r] [Citation(s) in RCA: 344] [Impact Index Per Article: 31.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Joseph R. Lane
- Department of Chemistry, University
of Waikato, Private Bag 3105, Hamilton 3240, New Zealand
| | - Julia Contreras-García
- UPMC Univ Paris 06, UMR 7616
CNRS, Laboratoire de Chimie Théorique, Case Courrier 137, 4
Place Jussieu, F-75005, Paris, France
| | - Jean-Philip Piquemal
- UPMC Univ Paris 06, UMR 7616
CNRS, Laboratoire de Chimie Théorique, Case Courrier 137, 4
Place Jussieu, F-75005, Paris, France
| | - Benjamin J. Miller
- Department of Chemistry, University
of Otago, P.O. Box 56, Dunedin, New Zealand
| | - Henrik G. Kjaergaard
- Department of Chemistry, University
of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark
| |
Collapse
|
45
|
Du L, Mackeprang K, Kjaergaard HG. Fundamental and overtone vibrational spectroscopy, enthalpy of hydrogen bond formation and equilibrium constant determination of the methanol-dimethylamine complex. Phys Chem Chem Phys 2013; 15:10194-206. [PMID: 23695525 DOI: 10.1039/c3cp50243k] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We have measured gas phase vibrational spectra of the bimolecular complex formed between methanol (MeOH) and dimethylamine (DMA) up to about 9800 cm(-1). In addition to the strong fundamental OH-stretching transition we have also detected the weak second overtone NH-stretching transition. The spectra of the complex are obtained by spectral subtraction of the monomer spectra from spectra recorded for the mixture. For comparison, we also measured the fundamental OH-stretching transition in the bimolecular complex between MeOH and trimethylamine (TMA). The enthalpies of hydrogen bond formation (ΔH) for the MeOH-DMA and MeOH-TMA complexes have been determined by measurements of the fundamental OH-stretching transition in the temperature range from 298 to 358 K. The enthalpy of formation is found to be -35.8 ± 3.9 and -38.2 ± 3.3 kJ mol(-1) for MeOH-DMA and MeOH-TMA, respectively, in the 298 to 358 K region. The equilibrium constant (Kp) for the formation of the MeOH-DMA complex has been determined from the measured and calculated transition intensities of the OH-stretching fundamental transition and the NH-stretching second overtone transition. The transition intensities were calculated using an anharmonic oscillator local mode model with dipole moment and potential energy curves calculated using explicitly correlated coupled cluster methods. The equilibrium constant for formation of the MeOH-DMA complex was determined to be 0.2 ± 0.1 atm(-1), corresponding to a ΔG value of about 4.0 kJ mol(-1).
Collapse
Affiliation(s)
- Lin Du
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark
| | | | | |
Collapse
|
46
|
Olbert-Majkut A, Ahokas J, Pettersson M, Lundell J. Visible Light-Driven Chemistry of Oxalic Acid in Solid Argon, Probed by Raman Spectroscopy. J Phys Chem A 2013; 117:1492-502. [DOI: 10.1021/jp311749z] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Adriana Olbert-Majkut
- Faculty of Chemistry, Wrocław University, F. Joliot-Curie 14, 50-383
Wrocław, Poland
| | | | | | | |
Collapse
|
47
|
Evangelisti L, Gou Q, Spada L, Feng G, Caminati W. Conformational analysis of 1,4-butanediol: A microwave spectroscopy study. Chem Phys Lett 2013. [DOI: 10.1016/j.cplett.2012.11.080] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
48
|
2,4-Dichlorophenoxyacetic Acid Derived Schiff Base and Its Lanthanide(III) Complexes: Synthesis, Characterization, Spectroscopic Studies, and Plant Growth Activity. J CHEM-NY 2013. [DOI: 10.1155/2013/810892] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
2,4-Dichlorophenoxyacetic acid derived Schiff base (HL) and its lanthanide [La(III), Pr(III), Nd(III), Sm(III), Eu(III), Gd(III), Dy(III), Y(III)] complexes were synthesized and characterized by various spectroscopic (1H,13C, DEPT and 2D HMQC NMR, FT-IR, UV-Vis, and mass) techniques and other analytical methods. HL exhibits “E” and “Z” isomerism and was confirmed by variable temperature1H NMR studies. The spectral and analytical data reveals the bidentate coordination of HL to lanthanide(III) ion, through carboxylic acid group via deprotonation. Fluorescence spectrum of europium complex shows bands at 578, 592, and 612 nm assignable toD05→F07,D05→F17, andD05→F27, respectively. Auxin activity of HL and lanthanum(III) complex on wheat seeds (Triticum durum) was measured at different concentrations. The percentage germination, root length, and shoot length were recorded. An enhancement in the plant growth activity of the ligand was observed on complexation and the best activity was observed at 10−6 M concentration.
Collapse
|
49
|
Yagi K, Keçeli M, Hirata S. Optimized coordinates for anharmonic vibrational structure theories. J Chem Phys 2012. [DOI: 10.1063/1.4767776] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
|
50
|
Du L, Lane JR, Kjaergaard HG. Identification of the dimethylamine-trimethylamine complex in the gas phase. J Chem Phys 2012; 136:184305. [PMID: 22583285 DOI: 10.1063/1.4707707] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We have identified the dimethylamine-trimethylamine complex (DMA-TMA) at room temperature in the gas phase. The Fourier transform infrared (FTIR) spectrum of DMA-TMA in the NH-stretching fundamental region was obtained by spectral subtraction of spectra of each monomer. Explicitly correlated coupled cluster calculations were used to determine the minimum energy structure and interaction energy of DMA-TMA. Frequencies and intensities of NH-stretching transitions were also calculated at this level of theory with an anharmonic oscillator local mode model. The fundamental NH-stretching intensity in DMA-TMA is calculated to be approximately 700 times larger than that of the DMA monomer. The measured and calculated intensity is used to determine a room temperature equilibrium constant of DMA-TMA of 1.7 × 10(-3) atm(-1) at 298 K.
Collapse
Affiliation(s)
- Lin Du
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark
| | | | | |
Collapse
|