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Verevkin SP, Portnova SV, Emel'yanenko VN, Nagrimanov RN, Varfolomeev MA. Experimental and computational thermochemistry: how strong is the intramolecular hydrogen bond in alkyl 2-hydroxybenzoates (salicylates). Phys Chem Chem Phys 2023; 25:21200-21214. [PMID: 37530056 DOI: 10.1039/d3cp01677c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/03/2023]
Abstract
Hydrogen bonding (HB) is a fascinating phenomenon that exhibits unusual properties in organic and biomolecules. The qualitative manifestation of hydrogen bonds is known in numerous chemical processes. However, quantifying HB strength is a challenging task, especially in the case of intra-molecular hydrogen bonds. It is qualitatively well established that the alkyl 2-hydroxybenzoates have strong intra-HB. The thermochemical methods suitable for the determination of intra-HB strength were the focus of this study. The experimental gas phase formation enthalpies for alkyl 2-hydroxybenzoates (including methyl, ethyl, n-propyl and n-butyl) at 298.15 K were derived from a combination of vapour pressure measurements and high-precision combustion calorimetry and validated by the quantum chemical methods G3MP2 and G4. The intra-HB strength in methyl 2-hydroxybenzoate was determined from the evaluated gas-phase enthalpies of formation by comparing the energies of cis- and trans- conformers, by well-balanced reactions, the "para-ortho" method and the "HB and Out" method. All these methods give a common level of intra-molecular hydrogen bond strength of -43 kJ mol-1. The intra-HB strength was found to be independent of the chain length of the alkyl 2-hydroxybenzoates.
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Affiliation(s)
- Sergey P Verevkin
- Competence Centre CALOR, Department Life, Light &Matter of Faculty of Interdisciplinary Research at University of Rostock, 18059, Rostock, Germany.
- Department of Physical Chemistry, Kazan Federal University, 420008 Kazan, Russia
| | - Svetlana V Portnova
- Chemical-Technological Department, Samara State Technical University, Samara 443100, Russia
| | - Vladimir N Emel'yanenko
- Competence Centre CALOR, Department Life, Light &Matter of Faculty of Interdisciplinary Research at University of Rostock, 18059, Rostock, Germany.
| | - Ruslan N Nagrimanov
- Department of Physical Chemistry, Kazan Federal University, 420008 Kazan, Russia
| | - Mikhail A Varfolomeev
- Department of Physical Chemistry, Kazan Federal University, 420008 Kazan, Russia
- Department of Petroleum Engineering, Kazan Federal University, 420008 Kazan, Russia
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El Hafidi S, Bakhy K, Ouhssine M, Benzakour A, Khamar H, Casanova J, Paoli M, Tomi F. Composition and Chemical Variability of the Essential Oil from Aerial Parts of Cladanthus scariosus, an Endemic Species to the Moroccan High Atlas. Chem Biodivers 2023; 20:e202201022. [PMID: 36520049 DOI: 10.1002/cbdv.202201022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 12/15/2022] [Accepted: 12/15/2022] [Indexed: 12/23/2022]
Abstract
Cladanthus scariosus (Ball) Oberpr. & Vogt is endemic to Moroccan High Atlas. It is known under the vernacular names Irezghi or Irezgui. Three essential oil samples have been isolated from aerial parts and analyzed by combination of chromatographic and spectroscopic techniques [gas chromatography (GC) in combination with retention indices (RI), gas chromatography-mass spectrometry (GC/MS) and 13 C-NMR spectroscopy]. The compositions of oil samples were dominated by monoterpenes: α-pinene sabinene, and terpinen-4-ol. Chamazulene and dihydrochamazulene isomers as well as various hemiterpene esters and analogs have been identified. To evidence a chemical variability, statistical analysis performed on 13 oil sample compositions allowed partitioning into three groups, mainly differentiated by their contents of sabinene, camphor, borneol, terpinen-4-ol, and germacrene D.
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Affiliation(s)
- Souad El Hafidi
- Faculty of Science, Laboratory of Natural Resources and Sustainable Development, University Ibn Tofail, BP 242, 14000, Kenitra, Morocco
| | - Khadija Bakhy
- National Institute of Agricultural Research (INRA), Research Unit on Aromatic and Medicinal Plant, BP 6570, Rabat-Instituts Rabat, Morocco
| | - Mohammed Ouhssine
- Faculty of Science, Laboratory of Natural Resources and Sustainable Development, University Ibn Tofail, BP 242, 14000, Kenitra, Morocco
| | - Abderrahim Benzakour
- Faculty of Science, Laboratory of Natural Resources and Sustainable Development, University Ibn Tofail, BP 242, 14000, Kenitra, Morocco
| | - Hamid Khamar
- Scientific Institute, Department of Botany and Plant Ecology, University Mohammed V, BP 703, Rabat, 10106, Morocco
| | - Joseph Casanova
- Université de Corse-CNRS, UMR 6134 SPE, Equipe Chimie et Biomasse, Ajaccio, France
| | - Mathieu Paoli
- Université de Corse-CNRS, UMR 6134 SPE, Equipe Chimie et Biomasse, Ajaccio, France
| | - Félix Tomi
- Université de Corse-CNRS, UMR 6134 SPE, Equipe Chimie et Biomasse, Ajaccio, France
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Lipp SV, Krasnykh EL, Levanova SV. Retention indices of symmetric dicarboxylic acid esters. JOURNAL OF ANALYTICAL CHEMISTRY 2011. [DOI: 10.1134/s1061934808040072] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Santiuste JM, Lebrón-Aguilar R, Quintanilla-López JE. Retention Indices of 55 Solutes Belonging to Eight Monofunctional Groups Homologous Series on 14 Chromatographic Capillary Columns. Chromatographia 2010. [DOI: 10.1365/s10337-010-1663-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Castello G, Moretti P, Vezzani S. Retention models for programmed gas chromatography. J Chromatogr A 2009; 1216:1607-23. [DOI: 10.1016/j.chroma.2008.11.049] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2008] [Revised: 11/17/2008] [Accepted: 11/19/2008] [Indexed: 11/29/2022]
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Görgényi M, Fekete ZA, Van Langenhove H, Dewulf J. Temperature dependence of the Kováts retention index. Convex or concave curves. J Chromatogr A 2008; 1206:178-85. [PMID: 18760787 DOI: 10.1016/j.chroma.2008.08.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2008] [Revised: 08/03/2008] [Accepted: 08/04/2008] [Indexed: 10/21/2022]
Abstract
The non-linearity in the temperature dependence of the Kováts index, I (the formation of convex or concave curves) was characterized by the second derivative, d2I/dT2. The expression deduced on a purely mathematical-physicochemical basis is d2I/dT2 = [2TDeltaS(CH2)dI/dT-100deltaDeltaCp]/TDeltaG(CH2). The solute-dependent factor for dI/dT, d2I/dT2, and the extreme temperature in the I vs. T relationship is deltaDeltaCp, which is the molar solvation heat capacity difference between the solute and a hypothetical n-alkane which elutes at the same time as the given solute, while the solvent-dependent factors are the solvation entropy and free energy of the methylene unit, DeltaS(CH2) and DeltaG(CH2). Experimentally, convex Ivs.T curves with a minimum are formed when deltaDeltaCp >> 0, while concave ones with a maximum are observed when deltaDeltaCp << 0. In the event of a linear temperature dependence, the former equation can be simplified: dI/dT = 100deltaDeltaCp/2TDeltaS(CH2). The deviation from linearity (higher d2I/dT2) increases with increasing deltaDeltaCp values. The model equations were tested from the dataset published by the Kováts group on C78 (19,24-dioctadecyldotetracontane), POH (18,23-dioctadecyl-1-untetracontenol), PCN (1-cyano-18,23-dioctadecyluntetracontane) and TMO (1,38-dimethoxy-17,22-bis-(16-methoxyhexadecyl)-octatriacontane) and by present measurements on the Innowax phase.
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Affiliation(s)
- Miklós Görgényi
- Department of Physical Chemistry, University of Szeged, Rerrich Béla tér 1, H-6721 Szeged, Hungary.
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Santiuste JM, Tarján G, Ullrich E, Takács JM. Contribution to linearly programmed temperature gas chromatography. J Chromatogr A 2008; 1181:103-15. [DOI: 10.1016/j.chroma.2007.12.025] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2007] [Revised: 12/12/2007] [Accepted: 12/12/2007] [Indexed: 11/30/2022]
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Görgényi M, Dewulf J, Van Langenhove H. Temperature dependence of the Kováts retention index. J Chromatogr A 2006; 1137:84-90. [DOI: 10.1016/j.chroma.2006.09.091] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2006] [Revised: 09/28/2006] [Accepted: 09/29/2006] [Indexed: 11/24/2022]
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Hoskovec M, Grygarová D, Cvaeka J, Streinz L, Zima J, Verevkin SP, Koutek B. Determining the vapour pressures of plant volatiles from gas chromatographic retention data. J Chromatogr A 2005; 1083:161-72. [PMID: 16078703 DOI: 10.1016/j.chroma.2005.06.006] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The frequently used vapour pressure versus Kováts retention index relationship has been evaluated in terms of its universal applicability, highlighting the problems associated with predicting the vapour pressures of structurally divergent organic compounds from experimentally measured isothermal Kováts retention indices. Two models differing in approximations adopted to express the activity coefficient ratio have been evaluated using 32 plant volatiles of different structural types as a test set. The validity of these models was established by checking their ability to reproduce 22 vapour pressures known from independent measurements. Results of the comparison demonstrated that (i) the original model, based on the assumption of equal activity coefficients for the test and reference substances, led, as expected, to a poor correlation (r2 = 89.1% only), with significantly deviating polar compounds and (ii) the model showed significant improvement after incorporating a new empirical term related to vaporization entropy and boiling point. The addition of this term allowed more than 99% of the vapour pressure variance to be accounted for. The proposed model compares favourably with existing correlations, while having an added advantage of providing a convenient tool for vapour pressure determination of chemically divergent chemicals.
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Affiliation(s)
- Michal Hoskovec
- Department of Natural Products, Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nám. 2, CZ-166 10 Prague 6, Czech Republic
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Görgényi M, Héberger K. Minimum in the temperature dependence of the Kováts retention indices of nitroalkanes and alkanenitriles on an apolar phase. J Chromatogr A 2003; 985:11-9. [PMID: 12580465 DOI: 10.1016/s0021-9673(02)01842-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The Kováts retention indices (I) of 1-nitroalkanes and alkanenitriles were determined on polydimethylsiloxane and Innowax (polyethylene glycol) columns in a wide temperature range. The temperature dependence of the retention indices exhibits a definite minimum for the early members of the homologous series. The position of the minimum shifts to lower temperatures with increasing carbon atom number of the solute. The thermodynamic explanation of an extreme in the I vs. T function is the higher solvation heat capacities of nitroalkanes and alkanenitriles relative to those of the reference n-alkanes, owing to the deviation from the ideal state in the solution. A novel equation was derived which describes the minimum in the I vs. T function, too.
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Affiliation(s)
- Mikiós Görgényi
- Department of Physical Chemistry, University of Szeged, P.O. Box 105 H-6701 Szeged, Hungary.
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Héberger K, Görgényi M, Kowalska T. Temperature dependence of Kováts indices in gas chromatography revisited. J Chromatogr A 2002; 973:135-42. [PMID: 12437171 DOI: 10.1016/s0021-9673(02)01198-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Temperature dependence of the Kováts retention index (I) was measured for some aliphatic ketones and aldehydes on a poly(dimethyl siloxane) (HP-1) stationary phase. An interesting minimum (non-linearity) was observed for the I versus isothermal column temperature (T) relationships. A novel empirical model is proposed: I=A+B/T+C ln T, where A, B and Care equation constants and B/C = T(min). A detailed statistical analysis clearly shows superiority of the extended model (i.e., of this containing the logarithm of the temperature (ln T) term) over the earlier established Antoine-type reciprocal equation. The minimum temperature (and the energy like quantity=RT(min), where R is the gas constant) changes in a systematic manner. The factors effecting the (RT(min)) term are as follows: (i) this term decreases with the increase of the molecular mass of the respective oxo compounds; (ii) ketones have higher absolute values of (RT(min) than aldehydes; (iii) branching of the carbon chain lowers the mentioned (RT(min)). This enthalpy term is unambiguously bound to the polarity of solutes.
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Affiliation(s)
- Károly Héberger
- Institute of Chemistry, Chemical Research Center, Hungarian Academy of Sciences, Budapest.
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Tudor E. Analysis of the equations for the temperature dependence of the retention index. II. Physico-chemical meaning of the parameters. J Chromatogr A 1999; 859:49-57. [PMID: 10563415 DOI: 10.1016/s0021-9673(99)00847-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
A general expression for the meaning of various parameters from the retention index-temperature equations was found. This is a linear combination of two solute dependent factors consisting of differences of enthalpies and respective entropies of solution, between the solute and the reference inferior n-alkane. The particular coefficients for each parameter are stationary phase dependent factors. They were calculated from methylene contributions to the thermodynamic functions of solution in SE-30 and Carbowax-20M, revealing the influence of the used temperature range. A short review of structural influences on dI/dT is included.
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Affiliation(s)
- E Tudor
- Institute of Physical Chemistry I. G. Murgulescu, Romanian Academy, Bucharest
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Tudor E. Analysis of the equations for the temperature dependence of the retention index. I. Relation between equations. J Chromatogr A 1999; 858:65-78. [PMID: 10544892 DOI: 10.1016/s0021-9673(99)00802-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The relation between the parameters of several equations for the retention index temperature dependence was established, taking the hyperbola deduced from the retention theory as starting point. The transformation factors depend only on methylene contributions to the thermodynamic functions of solution and temperature. Their evolution with the mean temperature of the range was illustrated for SE-30 and Carbowax-20M glass capillary columns. On this basis the post-run standardisation of dI/dT values at a reference mean temperature is possible. Examples and statistical correlation between series of parameters from different equations for perfumery solutes were shown.
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Affiliation(s)
- E Tudor
- Institute of Physical Chemistry I.G. Murgulescu, Romanian Academy, Bucharest, Romania
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