Browse
Submit Data
Databases
API
Help

Dataset Information

14 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

(±)-2-Oxocyclo-penta-neacetic acid: catemeric hydrogen bonding in a ?-keto acid.

ABSTRACT: The title racemate, C(7)H(10)O(3), aggregates in the solid as acid-to-ketone hydrogen-bonding catemers [O?O = 2.7050?(13)?Å and O-H?O = 166.1?(17)°] having glide-related components. Four such heterochiral chains, paired centrosymmetrically about (, , ) in the cell, proceed through the cell in the 010 direction, with alignment with respect to the c axis of ++--.

SUBMITTER: Efthimiopoulos G

PROVIDER: S-EPMC2969029 | biostudies-literature | 2009 Mar

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

(±)-2-Oxocyclo-penta-neacetic acid: catemeric hydrogen bonding in a γ-keto acid.

Efthimiopoulos Georgia G Papadakis Markos M MM Thompson Hugh W HW Lalancette Roger A RA

Acta crystallographica. Section E, Structure reports online 20090331 Pt 4

The title racemate, C(7)H(10)O(3), aggregates in the solid as acid-to-ketone hydrogen-bonding catemers [O⋯O = 2.7050 (13) Å and O-H⋯O = 166.1 (17)°] having glide-related components. Four such heterochiral chains, paired centrosymmetrically about (, , ) in the cell, proceed through the cell in the 010 direction, with alignment with respect to the c axis of ++--. ...[more]

PMID: 21582637

Similar Datasets

3-Oxocyclo-butane-carboxylic acid: hydrogen bonding in a small-ring ?-keto acid.

Project description:The title ketocarboxylic acid, C(5)H(6)O(3), is the smallest carboxy-cyclanone to have its crystal structure determined. It adopts a chiral conformation, by rotation of its carboxyl O atoms away from the plane of skeletal symmetry that passes through the carboxyl carbon and both atoms of the ketone carbonyl. The four-membered ring is non-planar, with a shallow fold of 14.3?(1)° along a line connecting the two ?-carbons of the ketone group. In the crystal, the molecules are linked by centrosymmetric hydrogen-bond pairing of ordered carboxylic acid groups [O?O = 2.6392?(12)?Å and O-H?O = 175.74?(15)°], yielding two different sets of dimers, related by by a 2(1) screw axis in c, in the cell. A C-H?O interaction is also present.

| S-EPMC2968635 | biostudies-literature

4-Oxocyclo-hexa-neacetic acid: catemeric hydrogen bonding and spontaneous resolution of a single conformational enanti-omer in an achiral ∊-keto acid.

Project description:The asymmetric unit of the title compound, C(8)H(12)O(3), consists of a single conformational enanti-omer, which aggregates in the catemeric acid-to-ketone hydrogen-bonding mode [O⋯O = 2.682 (4) Å and O-H⋯O = 172 (6)°]. Four hydrogen-bonding chains of translationally related mol-ecules pass through the cell orthogonal to the 4(3) screw axis along c, alternating in the 110 and the 10 direction, with alignment with respect to this axis of + + - -. Successive chains are rotated by 90° around the c axis. One C-H⋯O=C close contact, involving the carboxyl group, exists.

| S-EPMC2983244 | biostudies-literature

2-(2-Methyl-benzo-yl)benzoic acid: catemeric hydrogen bonding in a ?-keto acid.

Project description:The crystal structure of the title compound, C15H12O3, displays catemeric aggregation involving O-H?O hydrogen bonds progressing from the carboxyl group of one mol-ecule to the ketone O atom of another glide-related neighbor. The mol-ecule is twisted, with the toluene 80.61?(3)° out of plane with respect to the phenyl group of the benzoic acid. The acid group makes a dihedral angle of 13.79?(14)° with the attached phenyl ring. The mol-ecules are achiral, but the space group glide planes create alternating conformational chirality in the chain units. The four hydrogen-bonding chains progress along [001] in an A-A-B-B pattern (right-to-left versus left-to-right), and are related to each other by the center of symmetry at (0.5, 0.5, 0.5) in the chosen cell. There is one close contact (2.54?Å) between a phenyl H atom and the acid carbonyl from a symmetry-related mol-ecule.

| S-EPMC3790413 | biostudies-other

(±)-trans-3-Oxo-1,2,3,4,4a,9,10,10a-octa-hydro-phenanthrene-10a-carboxylic acid: catemeric hydrogen bonding in a ?-keto acid.

Project description:The title compound, C(15)H(16)O(3), aggregates as hydrogen-bonded catemers progressing from each carboxyl to the ketone of a screw-related neighbor [O?O = 2.6675?(14)?Å and O-H?O = 170°]. Two parallel centrosymmetrically related single-strand hydrogen-bonding helices proceed through the cell in the b-axis direction. The packing includes three inter-molecular C-H?O=C close contacts, involving both the ketone and the carboxyl group. The structure is isomorphous with that of the previously described ?(4) ?,?-unsaturated ketone.

| S-EPMC2960539 | biostudies-literature

Intramolecular OH⋅⋅⋅Fluorine Hydrogen Bonding in Saturated, Acyclic Fluorohydrins: The γ-Fluoropropanol Motif.

Project description:Fluorination is commonly exercised in compound property optimization. However, the influence of fluorination on hydrogen-bond (HB) properties of adjacent functional groups, as well as the HB-accepting capacity of fluorine itself, is still not completely understood. Although the formation of OH⋅⋅⋅F intramolecular HBs (IMHBs) has been established for conformationally restricted fluorohydrins, such interaction in flexible compounds remained questionable. Herein is demonstrated for the first time-and in contrast to earlier reports-the occurrence of OH⋅⋅⋅F IMHBs in acyclic saturated γ-fluorohydrins, even for the parent 3-fluoropropan-1-ol. The relative stereochemistry is shown to have a crucial influence on the corresponding (h1) JOH⋅⋅⋅F values, as illustrated by syn- and anti-4-fluoropentan-2-ol (6.6 and 1.9 Hz). The magnitude of OH⋅⋅⋅F IMHBs and their strong dependence on the overall molecular conformational profile, fluorination motif, and alkyl substitution level, is rationalized by quantum chemical calculations. For a given alkyl chain, the "rule of shielding" applies to OH⋅⋅⋅F IMHB energies. Surprisingly, the predicted OH⋅⋅⋅F IMHB energies are only moderately weaker than these of the corresponding OH⋅⋅⋅OMe. These results provide new insights of the impact of fluorination of aliphatic alcohols, with attractive perspectives for rational drug design.

| S-EPMC4676915 | biostudies-literature

Hydrogen Bonding Phase-Transfer Catalysis with Ionic Reactants: Enantioselective Synthesis of γ-Fluoroamines.

Project description:Ammonium salts are used as phase-transfer catalysts for fluorination with alkali metal fluorides. We now demonstrate that these organic salts, specifically azetidinium triflates, are suitable substrates for enantioselective ring opening with CsF and a chiral bis-urea catalyst. This process, which highlights the ability of hydrogen bonding phase-transfer catalysts to couple two ionic reactants, affords enantioenriched γ-fluoroamines in high yields. Mechanistic studies underline the role of the catalyst for phase-transfer, and computed transition state structures account for the enantioconvergence observed for mixtures of achiral azetidinium diastereomers. The N-substituents in the electrophile influence the reactivity, but the configuration at nitrogen is unimportant for the enantioselectivity.

| S-EPMC7441491 | biostudies-literature

Hydrogen Bonding Networks Enable Bronsted Acid-Catalyzed Carbonyl-Olefin Metathesis.

Project description:Synthetic chemists have learned to mimic nature in using hydrogen bonds and other weak interactions to dictate the spatial arrangement of reaction substrates and to stabilize transition states to enable highly efficient and selective reactions. The activation of a catalyst molecule itself by hydrogen-bonding networks, in order to enhance its catalytic activity to achieve a desired reaction outcome, is less explored in organic synthesis, despite being a commonly found phenomenon in nature. Herein, we show our investigation into this underexplored area by studying the promotion of carbonyl-olefin metathesis reactions by hydrogen-bonding-assisted Brønsted acid catalysis, using hexafluoroisopropanol (HFIP) solvent in combination with para-toluenesulfonic acid (pTSA). Our experimental and computational mechanistic studies reveal not only an interesting role of HFIP solvent in assisting pTSA Brønsted acid catalyst, but also insightful knowledge about the current limitations of the carbonyl-olefin metathesis reaction.

| S-EPMC9303705 | biostudies-literature

Tannic Acid as a Natural Crosslinker for Catalyst-Free Silicone Elastomers From Hydrogen Bonding to Covalent Bonding.

Project description:The construction of silicone elastomers crosslinked by a natural crosslinker under a catalyst-free method is highly desirable. Herein we present catalyst-free silicone elastomers (SEs) by simply introducing tannic acid (TA) as a natural crosslinker when using poly (aminopropylmethylsiloxane-co-dimethylsiloxane) (PAPMS) as the base polymer. The crosslinked bonding of these SEs can be easily changed from hydrogen bonding to covalent bonding by altering the curing reaction from room temperature to heating condition. The formability and mechanical properties of the SEs can be tuned by altering various factors, including processing technique, the amount of TA and aminopropyl-terminated polydimethylsiloxane, the molecular weight and -NH2 content of PAPMS, and the amount of reinforcing filler. The hydrogen bonding was proved by the reversible crosslinking of the elastomers, which can be gradually dissolved in tetrahydrofuran and re-formed after removing the solvent. The covalent bonding was proved by a model reaction of catechol and n-decylamine and occurred through a combination of hydroxylamine reaction and Michael addition reaction. These elastomers exhibit good thermal stability and excellent hydrophobic property and can bond iron sheets to hold the weight of 500 g, indicating their promising as adhesives. These results reveal that TA as a natural product is a suitable "green" crosslinker for the construction of catalyst-free silicone elastomers by a simple crosslinking strategy. Under this strategy, TA and more natural polyphenols could be certainly utilized as crosslinkers to fabricate more organic elastomers by selecting amine-containing polymers and further explore their extensive applications in adhesives, sealants, insulators, sensors, and so forth.

| S-EPMC8558560 | biostudies-literature

Composition-Dependent Hydrogen-Bonding Motifs and Dynamics in Bronsted Acid-Base Mixtures.

Project description:In recent years the interaction of organophosphates and imines, which is at the core of Brønsted acid organocatalysis, has been established to be based on strong ionic hydrogen bonds. Yet, besides the formation of homodimers consisting of two acid molecules and heterodimers consisting of one acid and one base, also multimeric molecular aggregates are formed in solution. These multimeric aggregates consist of one base and several acid molecules. The details of the intermolecular bonding in such aggregates, however, have remained elusive. To characterize composition-dependent bonding and bonding dynamics in these aggregates, we use linear and nonlinear infrared (IR) spectroscopy at varying molar ratios of diphenyl phosphoric acid and quinaldine. We identify the individual aggregate species, giving rise to the structured, strong, and very broad infrared absorptions, which span more than 1000 cm-1. Linear infrared spectra and density functional theory calculations of the proton transfer potential show that doubly ionic intermolecular hydrogen bonds between the acid and the base lead to absorptions which peak at ∼2040 cm-1. The contribution of singly ionic hydrogen bonds between an acid anion and an acid molecule is observed at higher frequencies. As common to such strong hydrogen bonds, ultrafast IR spectroscopy reveals rapid, ∼ 100 fs, dissipation of energy from the proton transfer coordinate. Yet, the full dissipation of the excess energy occurs on a ∼0.8-1.1 ps time scale, which becomes longer when multimers dominate. Our results thus demonstrate the coupling and collectivity of the hydrogen bonds within these complexes, which enable efficient energy transfer.

| S-EPMC7443859 | biostudies-literature

Bioactivity of Isostructural Hydrogen Bonding Frameworks Built from Pipemidic Acid Metal Complexes.

Project description:We report herein three novel complexes whose design was based on the approach that consists of combining commercially available antibiotics with metals to attain different physicochemical properties and promote antimicrobial activity. Thus, new isostructural three-dimensional (3D) hydrogen bonding frameworks of pipemidic acid with manganese (II), zinc (II) and calcium (II) have been synthesised by mechanochemistry and are stable under shelf conditions. Notably, the antimicrobial activity of the compounds is maintained or even increased; in particular, the activity of the complexes is augmented against Escherichia coli, a representative of Gram-negative bacteria that have emerged as a major concern in drug resistance. Moreover, the synthesised compounds display similar general toxicity (Artemia salina model) levels to the original antibiotic, pipemidic acid. The increased antibacterial activity of the synthesised compounds, together with their appropriate toxicity levels, are promising outcomes.

| S-EPMC7287797 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data