A comprehensive description of the free energy of an intramolecular hydrogen bond as a function of solvation: NMR study

Beeson, Craig C.; Phạm, Ngọc Hiếu; Shipps, Gerald W.; Dix, Thomas A.

doi:10.1021/ja00068a043

Cited by 38 publications

(37 citation statements)

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“…Carefully applied, the technique may also be used to determine the extent and relative energy of intramolecular H bonds. [42] [59] FT-IR spectra were recorded for compounds 1؊16 in dry CH 2 Cl 2 at concentrations at which the intermolecular association was reduced to a minimum, taking into account the dissolution limits of the compounds. The frequencies of the OϪH bond stretching vibrations of the free [ν(ΟΗ) free ] and intramolecular Hbonded [ν(ΟΗ) intra ] hydroxy groups are given in Table 3.…”

Section: H Nmr and Ft-ir Datamentioning

confidence: 99%

“…[42,60,65] A series of 1,3-diols (12؊16) was chosen in order to evaluate the influence of conformational flexibility on the H-bonding network (see Figure 1). By this criterion, these compounds can be classified into two groups.…”

Section: Intramolecular Hydrogen Bonds In the 13-diols 12؊16mentioning

confidence: 99%

“…Work related to the factors underlying the intramolecular H-bond strength in hydroxylated compounds simpler than carbohydrates, [39Ϫ41] as well as in hydroxy ethers, [42] has been reported. These studies examined how intramolecular OH···OH H bonds affect the formation of intermolecular H bonds in simple aliphatic diols.…”

Section: Introductionmentioning

confidence: 99%

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Carbohydrate Hydrogen-Bonding Cooperativity − Intramolecular Hydrogen Bonds and Their Cooperative Effect on Intermolecular Processes − Binding to a Hydrogen-Bond Acceptor Molecule

et al. 2002

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The high hydroxy (OH) group content in carbohydrates makes the study of carbohydrate OH···XH and OH···X Hbond energetics fundamental to understanding of carbohydrate recognition. There is, however, a relative lack of knowledge concerning the factors that allow a carbohydrate to participate in recognition events stabilised by intermolecular H bonds. We therefore present here a systematic study on the factors that determine the formation of a well-defined intramolecular H-bonding network between carbohydrate hydroxy groups, and its cooperative or anti-cooperative influence on selected intermolecular processes mediated by H bonds. With this in mind, we first determined the H-bonding networks of a series of carbohydrate derivatives − monoalcohols, 1,2-and 1,3-diols and amidoalcohols − by 1 H NMR and FT-IR spectroscopy. The hydroxy groups of these compounds showed different abilities to form intramolecular H bonds, depending on their relative positions and configurations on

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Section: H Nmr and Ft-ir Datamentioning

confidence: 99%

Section: Intramolecular Hydrogen Bonds In the 13-diols 12؊16mentioning

confidence: 99%

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Carbohydrate Hydrogen-Bonding Cooperativity − Intramolecular Hydrogen Bonds and Their Cooperative Effect on Intermolecular Processes − Binding to a Hydrogen-Bond Acceptor Molecule

et al. 2002

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“…The effective dielectric is used as a simplified parameter to describe the ability of the environment to stabilize isolated charges and dipoles: the better this stabilization is accomplished, the less the energetic consequences of charge development. The effective dielectric is distinct from the bulk dielectric constant; it can account for the impact of the molecular properties of the local environment on interactions between adjacent groups, such as H bonds (41)(42)(43)(44)(45).…”

Section: Origins Of the Larger Brønsted Slopes Of H Bonding Inmentioning

confidence: 99%

The change in hydrogen bond strength accompanying charge rearrangement: Implications for enzymatic catalysis

Shan

Herschlag²

1996

Proc. Natl. Acad. Sci. U.S.A.

186

197

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The equilibrium for formation of the intramolecular hydrogen bond (K HB ) in a series of substituted salicylate monoanions was investigated as a function of ⌬pK a , the difference between the pK a values of the hydrogen bond donor and acceptor, in both water and dimethyl sulfoxide. The dependence of log K HB upon ⌬pK a is linear in both solvents, but is steeper in dimethyl sulfoxide (slope ‫؍‬ 0.73) than in water (slope ‫؍‬ 0.05). Thus, hydrogen bond strength can undergo substantially larger increases in nonaqueous media than aqueous solutions as the charge density on the donor or acceptor atom increases. These results support a general mechanism for enzymatic catalysis, in which hydrogen bonding to a substrate is strengthened as charge rearranges in going from the ground state to the transition state; the strengthening of the hydrogen bond would be greater in a nonaqueous enzymatic active site than in water, thus providing a rate enhancement for an enzymatic reaction relative to the solution reaction. We suggest that binding energy of an enzyme is used to fix the substrate in the low-dielectric active site, where the strengthening of the hydrogen bond in the course of a reaction is increased.Electronic rearrangement typically occurs in the course of a reaction, resulting in changes in the charge density of functional groups on the reactant. This is shown in Scheme I for the example of the triosephosphate isomerase (TIM) reaction.As the reaction proceeds from the ground state to the transition state, negative charge accumulates on the carbonyl oxygen, as reflected by the Ϸ10-unit increase in the pK a of this group. [The pK a of the carbonyl oxygen in the ground state is estimated to be Ϫ2 to 0; the pK a of the enol hydroxyl in a fully enolic transition state is estimated to be Ϸ10 (1).] The hydrogen bond (H bond) from a histidine residue of TIM to the carbonyl oxygen can be strengthened by this charge buildup (depicted by the darker dots in Scheme I). However, to obtain a rate enhancement relative to the solution reaction, the strengthening of an H bond to an enzymatic group in the course of a reaction must be greater than the strengthening of the corresponding H bond to water.Could the environment of the enzyme active site increase the change in H bond strength accompanying charge rearrangements relative to that in water? To address this question, we used the aprotic organic solvent dimethyl sulfoxide (DMSO) as a crude mimic of the active site environment and investigated the energetics of the intramolecular H bond in a series of substituted salicylate monoanions in both DMSO and water. There is a larger increase in H bond strength in DMSO than in water as the pK a values of the H bonding groups are varied. We suggest that a substantial amount of catalysis can be obtained by enzymes from the greater strengthening of H bonds accompanying charge rearrangements in nonaqueous environments than in aqueous solutions. MATERIALS AND METHODS Materials.The indicators 2,6-di-tert-butyl-4-nitrophenol and 9-carboxym...

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“…124,132,133,135,137 Electrostatic effects: Electrostatic effects, mainly intramolecular hydrogen-bonding, are strongly sensitive to the nature and polarity of the solvent. Experimentally, intramolecular hydrogen-bonds in an aqueous environment can be detected only indirectly, for example, via NMR 37,[109][110][111][112]115,[124][125][126][138][139][140][141][142][143][144][145][146][147][148][149] or IR 110,[113][114][115]144,[149][150][151][152][153] spectroscopy. However, most studies to date have investigated model compounds (e.g., monosaccharide analogs) and only provided qualitative information on the existence or absence of a hydrogen-bond.…”

Section: Introductionmentioning

confidence: 99%

Conformation, dynamics, solvation and relative stabilities of selected β-hexopyranoses in water: a molecular dynamics study with the gromos 45A4 force field

Kräutler

Müller

Hünenberger

2007

Carbohydrate Research

139

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A comprehensive description of the free energy of an intramolecular hydrogen bond as a function of solvation: NMR study

Cited by 38 publications

References 1 publication

Carbohydrate Hydrogen-Bonding Cooperativity − Intramolecular Hydrogen Bonds and Their Cooperative Effect on Intermolecular Processes − Binding to a Hydrogen-Bond Acceptor Molecule

Carbohydrate Hydrogen-Bonding Cooperativity − Intramolecular Hydrogen Bonds and Their Cooperative Effect on Intermolecular Processes − Binding to a Hydrogen-Bond Acceptor Molecule

The change in hydrogen bond strength accompanying charge rearrangement: Implications for enzymatic catalysis

Conformation, dynamics, solvation and relative stabilities of selected β-hexopyranoses in water: a molecular dynamics study with the gromos 45A4 force field

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