CONFORMATIONAL EQUILIBRIA IN OPEN-CHAIN Α,β-Unsaturated KETONES

Noack, K.; Jones, Richard N.

doi:10.1139/v61-294

Cited by 66 publications

(21 citation statements)

References 7 publications

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“…As mentioned above, whether structures such as these two stereoisomers of methyl propenyl ketone actually interconvert depends on conditions including pH, temperature, and solvent, and in general on structural effects such as steric hindrance [ 25 ], conformer energy differences, and barriers to internal rotation [ 26 ]. However, all these effects are way beyond the scope of chemical structure identifiers or a database registration process that should be usable for millions of compounds.…”

Section: Enumeration Of Tautomersmentioning

confidence: 99%

Tautomerism in large databases

Sitzmann

Ihlenfeldt²,

Nicklaus

2010

J Comput Aided Mol Des

103

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We have used the Chemical Structure DataBase (CSDB) of the NCI CADD Group, an aggregated collection of over 150 small-molecule databases totaling 103.5 million structure records, to conduct tautomerism analyses on one of the largest currently existing sets of real (i.e. not computer-generated) compounds. This analysis was carried out using calculable chemical structure identifiers developed by the NCI CADD Group, based on hash codes available in the chemoinformatics toolkit CACTVS and a newly developed scoring scheme to define a canonical tautomer for any encountered structure. CACTVS’s tautomerism definition, a set of 21 transform rules expressed in SMIRKS line notation, was used, which takes a comprehensive stance as to the possible types of tautomeric interconversion included. Tautomerism was found to be possible for more than 2/3 of the unique structures in the CSDB. A total of 680 million tautomers were calculated from, and including, the original structure records. Tautomerism overlap within the same individual database (i.e. at least one other entry was present that was really only a different tautomeric representation of the same compound) was found at an average rate of 0.3% of the original structure records, with values as high as nearly 2% for some of the databases in CSDB. Projected onto the set of unique structures (by FICuS identifier), this still occurred in about 1.5% of the cases. Tautomeric overlap across all constituent databases in CSDB was found for nearly 10% of the records in the collection.

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Section: Enumeration Of Tautomersmentioning

confidence: 99%

Tautomerism in large databases

Sitzmann

Ihlenfeldt²,

Nicklaus

2010

J Comput Aided Mol Des

103

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“…In nature, there are two conformers of s- cis and s- trans MVKs (molecular sizes: 8.36 Å for s-cis and 7.53 Å for s-trans forms), 7 and their existence ratio depends on the temperature. 26−28 In our previous report, it was confirmed that the s-cis form of MVK is the preferred molecular geometry in the 5 12 6 4 cage of MVK + CH 4 sII hydrate in spite of its larger size and that an intracavity conformational change from the s-cis to s-trans form of MVK can be induced by γ-irradiation using an annealing process. 7 The relative energy difference between the two conformers is 0.6 kJ/mol obtained by DFT calculation using the B3LYP model and 6-311++G(d,p) basis set, and the torsional energy barrier from s-cis to s-trans is 6.56 kJ/mol.…”

Section: Resultsmentioning

confidence: 77%

Thermodynamic Stability of Structure II Methyl Vinyl Ketone Binary Clathrate Hydrates and Effects of Secondary Guest Molecules on Large Guest Conformation

et al. 2017

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Clathrate hydrates have received massive attention because of their potential application as energy storage materials. Host water frameworks of clathrate hydrates provide empty cavities that can capture not only small molecular guests but also radical species induced by γ-irradiation. In this work, we investigated structure II methyl vinyl ketone (MVK) binary clathrate hydrates with CH 4 , O 2 , and N 2 and the effects of secondary guest species on MVK conformation in the cavity of hydrate and on the thermodynamic stability of unirradiated and γ-irradiated hydrate phases. The present findings provide meaningful information to understand the nature of guest–host interactions in γ-irradiated clathrate hydrates and to open up practical applications for hydrate-based nanoreactors.

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“…It has been studied in the gas phase by microwave spectroscopy [21][22][23][24] and by vibrational spectroscopy in all three phases [25][26][27][28] and also in an argon matrix [29]. There is general agreement that the molecule exists in two conformers, s-trans (2) and s-cis (3) and a potential energy scan around the C2-C3 bond confirms this as shown in Figure 5.…”

Section: -Butene-2-one (Methyl Vinyl Ketone)mentioning

confidence: 68%

Structural and spectroscopic characterisation of C4 oxygenates relevant to structure/activity relationships of the hydrogenation of α,β-unsaturated carbonyls

Parker

Silverwood

Hamilton

et al. 2016

Spectrochimica Acta Part A: Molecular and Biomolecular Spectros

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Supported palladium catalysts are widely used in selective hydrogenation reactions, thus it is desirable to correlate product yields with catalyst performance, so as to optimize catalyst productivity. One method to achieve this goal is to use gas phase infrared spectroscopy to follow the evolution of the gas phase composition as a catalytic reaction progresses and hence determine the kinetics of the reaction. The method is critically dependent on reliable identification and assignment of the modes of each of the species that may be present. We plan to use the same method to investigate how the morphology of Pd crystallites can influence selectivity branching in gas phase hydrogenation reactions of α,β-unsaturated carbonyl compounds, specifically by following the hydrogenation of 3-butyne-2-one to 3-butene-2-one to 2-butanone and finally to 2-butanol. In the present work, we have investigated the conformational isomerism and calculated the vibrational spectra of the C4 oxygenates using density functional theory. The calculations are validated by comparison to the inelastic neutron scattering and infrared spectra of the compounds. KeywordsInelastic neutron scattering spectroscopy; Infrared spectroscopy; Density functional theory; Conformational isomerism Highlights• The conformational isomerism in 3-butyne-2-one, 3-butene-2-one, 2-butanone and 2-butanol oxygenates has been investigated.• Complete vibrational assignments for 3-butyne-2-one, 3-butene-2-one, 2-butanone and 2-butanol are obtained from density functional theory.• The assignments have been tested by comparison to inelastic neutron scattering spectra. Graphical abstract3

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CONFORMATIONAL EQUILIBRIA IN OPEN-CHAIN Α,β-Unsaturated KETONES

Cited by 66 publications

References 7 publications

Tautomerism in large databases

Tautomerism in large databases

Thermodynamic Stability of Structure II Methyl Vinyl Ketone Binary Clathrate Hydrates and Effects of Secondary Guest Molecules on Large Guest Conformation

Structural and spectroscopic characterisation of C4 oxygenates relevant to structure/activity relationships of the hydrogenation of α,β-unsaturated carbonyls

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