Intramolecular Hydrogen Bonding (Proton Transfer) of 1-Phenyl-1,3-butanedione

Matsuzawa, Hideyo; Nakagaki, Takashi; Iwahashi, Makio

doi:10.5650/jos.56.653

Cited by 12 publications

(8 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Hansen et al determined 12 a value of K = 1.12 (53% of Enol 2) for BZA in CH 2 Cl 2 at 227 K. This is in agreement with conclusions based on the resonance-assisted H-bond theory, proposed by Gilli et al for a series of b-diketones. 13 A recent variable-temperature NMR study 14 of BZA in CDCl 3 suggested a value of 1.83 for K. All these results corroborate the coexistence of two enol conformers (Scheme 1c) that are in dynamic equilibrium, with more preference to Enol 2 in solution. The fate of this equilibration upon electronic excitation (Scheme 1d) is unknown and so are the subsequent relaxation dynamics.…”

Section: Introductionsupporting

confidence: 56%

“…Recent NMR studies on BZA reported that 65% of enolization occurs in the phenyl side (Enol 2). 14 The slightly higher stability of Enol 2 was assigned to extended conjugation between the phenyl ring and CQCH-CQO as compared with the cross conjugation present in Enol 1 (where the phenyl group is conjugated only to the CQO bond). 30 Though the absorption spectrum of BZA has contributions from both the tautomers being in dynamic equilibrium, it cannot be deconvoluted into two separate ones since the individual contributions are not known.…”

Section: Ground-state Dynamicsmentioning

confidence: 99%

See 1 more Smart Citation

Monitoring ultrafast intramolecular proton transfer processes in an unsymmetric β-diketone

Verma

Steinbacher

Koch

et al. 2015

Phys. Chem. Chem. Phys.

View full text Add to dashboard Cite

We report the experimental determination of the intramolecular enol-enol tautomerization rate of an unsymmetric β-diketone, benzoylacetone, with femtosecond transient absorption in the ultraviolet. Initially, there is an equilibrium of two possible enolic structures in solution, which is disturbed upon UV excitation by exciting a disproportionate fraction of one enolic form. Comparison to symmetric β-diketones, acetylacetone and dibenzoylmethane, suggests that ground-state proton transfer gives rise to additional dynamics in benzoylacetone due to the dissimilarity of the two enolic forms. In the excited state of the molecules, the intramolecular H-bond is initially broken, followed by photochemical processes towards rotamer structures. Our studies therefore disclose intramolecular proton transfer among electronic ground as well as excited states of benzoylacetone. Considering the importance of β-diketones as a common model of enol-enol tautomerization and their resemblance to enzymatic enolates, the present study provides valuable information on the ultrafast mechanism of intramolecular proton transfer processes.

show abstract

Section: Introductionsupporting

confidence: 56%

Section: Ground-state Dynamicsmentioning

confidence: 99%

Monitoring ultrafast intramolecular proton transfer processes in an unsymmetric β-diketone

Verma

Steinbacher

Koch

et al. 2015

Phys. Chem. Chem. Phys.

View full text Add to dashboard Cite

show abstract

“…Tautomerisms are structural isomers that differ from one another on the basis of the position of proton(s) and double bonds; the carbon skeleton of the structure is unchanged [1]. It was first described by Laarin in 1886 [2].Keto-enol tautomerism in β-ketoester [3][4][5], β-diketones [6][7][8][9], β-ketonitrile [10], β-ketoamide [11][12][13], ortho-hydroxy Schiff bases [14][15][16][17], Azo dyes [18], alpha-ketophosphonates [19], and the 1,3,4-thiadiazole group with a 2,4-hydroxyphenyl function [20] have been studied using different spectroscopic techniques. Similarly, those compounds of type β-keto-enol derivatives containing heterocyclic moieties such as 4-hydroxycoumarin [21], Imidazoline derivatives [22], indol [23], and pyrazole, pyridine, thiophene, or furan [24] can exist as a keto-enol tautomerism.…”

Section: Introductionmentioning

confidence: 99%

Synthesis, Spectroscopic Studies and Keto-Enol Tautomerism of Novel 1,3,4-Thiadiazole Derivative Containing 3-Mercaptobutan-2-one and Quinazolin-4-one Moieties

et al. 2020

View full text Add to dashboard Cite

In this study, a novel 1,3,4-thiadiazole derivative containing 3-mercaptobutan-2-one and quinazolin-4-one moieties (Compound 3) is synthesized by the coupling of 2-amino-1,3,4-thiadiazole-5-(3-mercaptobutan-2-one) (Compound 1) with 2-Phenyl-4H-3,1-benzoxazin-4-one (Compound 2) in one molecule moiety. Compound 3 is found to exist as two types of intra-molecular hydrogen bonding with keto-enol tautomerism characters, which is further confirmed using FTIR, 1H-NMR, 13C-NMR, mass spectrometer, and UV-Visible spectra. The 1H-NMR and UV-Visible spectra of Compound 3 are investigated in different solvents such as methanol, chloroform, and DMSO. Compound 3 exhibits keto-enol tautomeric forms in solvents with different percentage ratios depending on the solvent polarity. The 1H-NMR and UV-Visible spectral results show that Compound 3 favors the keto over the enol form in polar aprotic solvents such as DMSO and the enol over the keto form in non-polar solvents such as chloroform. The 13C-NMR spectrum gives two singles at δ 204.5 ppm, due to ketonic carbon, and δ 155.5 ppm, due to enolic carbon, confirming the keto-enol tautomerism of Compound 3. Furthermore, the molecular ion at m/z 43 and m/z 407 in the mass spectrum of Compound 3 and fragmentation mechanisms proposed reveal the existence of the keto and enol forms, respectively.

show abstract

“…Given that proton transfer is intimately associated with H‐bonding and tunneling, which are two very important phenomena in chemical and biological systems, the literature is replete with investigations in this area . The proton is often used as a promoter and mediator in chemical reactions .…”

Section: Introductionmentioning

confidence: 99%

The π‐Tetrel Bond and its Influence on Hydrogen Bonding and Proton Transfer

Wei

Scheiner

2018

ChemPhysChem

View full text Add to dashboard Cite

The positive region that lies above the plane of F TO (T=C and Si) interacts with malondialdehyde (MDA), which contains an intramolecular H-bond. The T atom of F TO can lie either in the MDA molecular plane, forming a T⋅⋅⋅O tetrel bond, or F TO can stack directly above MDA in a parallel arrangement. The former structure is more stable than the latter, and in either case, F SiO engages in a much stronger interaction than does F CO, reaching nearly 200 kJ mol . The π-tetrel bond strengthens/weakens the MDA H-bond when the bond is formed to the hydroxyl/carbonyl group of MDA, and causes an accompanying inhibition/promotion of proton transfer within this H-bond; this effect is stronger for F SiO. These same aspects can be tuned by substituents placed on any of the C atoms of MDA, although their effects are not fully correlated with the electron-withdrawing or electron-releasing properties of the substituent. A new type of π-π tetrel bond occurs when the π-hole on the T atom of F TO approaches the middle carbon atom of MDA from above, and a similar configuration is also found between F TO and benzene. Evidence for extensive C⋅⋅⋅C π-π tetrel bonding in crystal materials is presented.

show abstract

Intramolecular Hydrogen Bonding (Proton Transfer) of 1-Phenyl-1,3-butanedione

Cited by 12 publications

References 18 publications

Monitoring ultrafast intramolecular proton transfer processes in an unsymmetric β-diketone

Monitoring ultrafast intramolecular proton transfer processes in an unsymmetric β-diketone

Synthesis, Spectroscopic Studies and Keto-Enol Tautomerism of Novel 1,3,4-Thiadiazole Derivative Containing 3-Mercaptobutan-2-one and Quinazolin-4-one Moieties

The π‐Tetrel Bond and its Influence on Hydrogen Bonding and Proton Transfer

Contact Info

Product

Resources

About