2 edition of hydrogen bond in crystals with reference to certain carbonylic acids. found in the catalog.
hydrogen bond in crystals with reference to certain carbonylic acids.
John McClelland Pollock
Written in English
Thesis (Ph. D.)--The Queen"s University of Belfast, 1955.
|The Physical Object|
The short hydrogen-bond interactions found in RGAE have equivalents in small-molecule structures. An examination of the short hydrogen bonds in RGAE, the calculated pK a values and solvent-accessibilities identified a buried carboxylic acid carboxylate hydrogen bond between Asp75 and Asp87 as the likely origin of the 18 p.p.m. signal. Similar Cited by: A hydrogen bond is a partially electrostatic attraction between a hydrogen (H) atom which is bound to a more electronegative atom or group, such as nitrogen (N), oxygen (O), or fluorine (F)—the hydrogen bond donor—and another adjacent atom bearing a lone pair of electrons—the hydrogen bond acceptor.. Hydrogen bonds can be intermolecular (occurring between separate molecules) or Author: Sgdfg.
How come carboxylic acids are often found to have double their actual molar mass? “It was recognised some decade ago that under certain conditions an atom of hydrogen is attracted by rather strong forces to two atoms instead of only one so that it may be considered to be acting as a bond between them. This is called the hydrogen bond.” Author: Derek Carr.  Although considerably less acidic than carboxylic acids (pK a =), scientists at Pfizer discovered that 3-hydroxyquinolinone-containing d-amino acid oxidase inhibitors can in fact establish hydrogen-bonding interactions within the enzyme active site, in a very similar fashion as carboxylic acid-containing inhibitors (cf., 64 and 65 Cited by:
1-Hydroxycyclohexanecarboxylic acid. 1-Hydroxy-cyclohexanecarboxylic acid. 1-hydroxycyclohexanecarboxylic acid. Cyclohexanecarboxylic acid, 1-hydroxy-. Because they are both hydrogen-bond acceptors (the carbonyl –C=O) and hydrogen-bond donors (the hydroxyl –OH), they also participate in hydrogen bonding. Together, the hydroxyl and carbonyl group form the functional group carboxyl. Carboxylic acids usually exist as dimers in nonpolar media due to their tendency to "self-associate".
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This special issue presents studies on hydrogen bonds in crystals, and specific compounds and specific H-bonded patterns existing in crystals are analyzed. However, the characteristics of the H-bond interactions are not only analyzed theoretically; this interaction is compared with other ones that steer the arrangement of molecules in crystals, for example halogen, tetrel or pnicogen bonds.
The consequences of the extensive linking of molecules by hydrogen bonds is classified according as to whether hydrogen bonds lead to: closed groups as in monobasic carboxylic acids; indefinite chains as in the dibasic acids; sheet structures as in succinimide; or space filling networks as in resorcinol and other clathrate structures.
bonding when there are available hydrogen-bond donors, and (3) the best hydrogen-bond donor and the best hydrogen-bond acceptor will preferentially form hydrogen bonds to one another.
Pauling, describing the hydrogen bond, refers directly to crystal structures, to ﬂuorine compounds, to. clathrate compounds, and to structures of alcohols or carboxylic acids. He describes the effect of the. hydrogen bond on the physical properties of substances, and in detail, the cooperativity H-bond by: C–HO hydrogen bonding in crystals.
Crystallography Reviews9 (), DOI: / Martin Jetzki, Ruth Signorell. The competition between hydrogen bonding and chemical change in carbohydrate by: Preliminary NMR studies on hydrogen bonding of carboxylic acid−carboxylate systems in an anhydrous, aprotic solvent are presented.
In all cases, a low-field resonance (16−20 ppm) indicative of strong hydrogen bonding was by: In this case the likelihood of forming a hydrogen bond from the carboxylic acid to the carboxamide is roughly the same as that of the carboxylic acid with itself (the homo-interaction).
The crystal structure of Indomethacin was first published by Kistenmacher & Marsh () and this structure has a carboxylic acid dimer interaction around a. This chapter emphases the important role of hydrogen bonding in crystal engineering for preparing fascinating architectures and engineering desired properties.
The relatively high directionality and strength of hydrogen bonds make the prediction and control of molecular orientation in organic solids practical and by: 1. 1. Introduction. According to Allen et al. (), when a 2-aminoheterocyclic ring containing an N sp 2 atom in the 1-position of the ring crystallizes in the presence of a carboxylic acid there is a 76% probability that the two groups will form a hydrogen-bonded graph set (Bernstein et al., ) dimer (as shown in Fig.
1 a).This probability is increased to 82% if proton transfer to the Cited by: The study considered carboxylic acid–imide combinations, of which the majority had hydrogen-bond acceptor groups (fluoro, nitro etc.) on the acid partner. Since the hydrogen-bond demands of the extra imide carbonyl acceptor cannot be complemented by acceptor groups on the partner molecules, co-crystal formation is curtailed due to high-energy Cited by: Is hydrogen bonding primarily electrostatic in nature.
How long are hydrogen bonds. What are the angular requirements on the acceptor and donor. What can computations tell us.
Do formyl hydrogen bonds exist. What is their role in reactivity. - + A H B - donor D acceptor d Selected References 1. "An Introduction to Hydrogen Bonding File Size: 1MB. We added new data for the integral intensities of v(OH) bands in spectra of crystalline acid salts of carboxylic acids with well-known structures and spectra .
As a result, we found that the parameters AA ~/2, Av and A~"2 are related to each other as they are for spectra of solutions with different hydrogen bonds, the latter interrelations Cited by: The X-ray crystal structures of the octa-ester and of the octa-acid were determined.
The three-dimensional conformation of the ester provided an interpenetrated compact packing of the molecular building blocks without any specific supramolecular interaction.
The two-dimensional character of the acid and the directionality of the hydrogen bond Cited by: 8. Five 1,3-alternate thiacalixarene derivatives bearing carboxylic acid and/or ureahydrogen-bonding groups were prepared and their crystal structures were determined by single-crystal X-ray.
Spectroscopic Properties of Alcohols Last updated; Save as PDF Page ID ; Contributors; The hydrogen-oxygen bond of a hydroxyl group gives a characteristic absorption band in the infrared but, as we may expect, this absorption is considerably influenced by hydrogen bonding. For example, in the vapor state (in which there is essentially no hydrogen bonding), ethanol gives an infrared.
A hydrogen bond (often informally abbreviated H-bond) is a partial intermolecular bonding interaction between a lone pair on an electron rich donor atom, particularly the second-row elements nitrogen (N), oxygen (O), or fluorine (F), and the antibonding molecular orbital of a bond between hydrogen (H) and a more electronegative atom or group.
Such an interacting system is generally denoted Dn. Our analysis of these 12 ICCs and the 9 relevant entries (including 4 hydrates) archived in the CSD reveals that charge-assisted hydrogen bonds between phenol moieties and chloride anions persist even in the presence of carboxylic acid moieties, which form carboxylic acid dimers in 11/21 crystal structures.
Carboxylic acidchloride Cited by: Increasing the negative charge of a hydrogen-bond acceptor using electron-donating substituents offers a significant improvement in hydrogen-bond driven synthesis of carboxylic acid⋯N-heterocycle by: Gong, W., Chu, D., Jiang, H. et al. Permanent porous hydrogen-bonded frameworks with two types of Brønsted acid sites for heterogeneous asymmetric catalysis.
Nat Com Cited by: 8. Pharmaceutical salt solvates (dimethyl sulfoxide, DMSO) of the drug triamterene with the coformers acetic, succinic, adipic, pimelic, azelaic and nicotinic acid and ibuprofen are prepared by liquid-assisted grinding and solvent-evaporative crystallization. The modified ΔpKa rule as proposed by Cruz-Cabeza [().
CrystEngComm, 14, –] is in close agreement with the results of this Cited by: 2. Summary. Functional groups related to the carbonyl group include the –CHO group of an aldehyde, the –CO– group of a ketone, the –CO 2 H group of a carboxylic acid, and the –CO 2 R group of an ester.
The carbonyl group, a carbon-oxygen double bond, is the key structure in these classes of organic molecules: Aldehydes contain at least one hydrogen atom attached to the carbonyl carbon. Making alcohols via hydrogen addition to C=O bonds is among the most widely applied reactions in chemistry. The transformation has also garnered renewed interest for generating commodity chemicals from biomass.
Korstanje et al. now show that a cobalt compound can catalyze hydrogenation of the C=O bonds in carboxylic acids. These constitute a particularly challenging substrate class, Cited by: Hydrogen–deuterium exchange (also called H–D or H/D exchange) is a chemical reaction in which a covalently bonded hydrogen atom is replaced by a deuterium atom, or vice versa.
It can be applied most easily to exchangeable protons and deuterons, where such a transformation occurs in the presence of a suitable deuterium source, without any catalyst.