MO study of molecular association of local anaesthetics of carbamate type

1983 ◽  
Vol 48 (2) ◽  
pp. 533-537 ◽  
Author(s):  
Milan Remko ◽  
Vladimír Frecer ◽  
Jozef Čižmárik
Keyword(s):  
Hydrogen Bonds ◽  
Oxygen Atom ◽  
Quantum Chemical ◽  
Local Anaesthetics ◽  
Carbonyl Oxygen ◽  
Molecular Association ◽  
Stable Complex ◽  
Intermolecular Hydrogen Bonds ◽  
Pcilo Method ◽  
Self Association

The quantum-chemical PCILO method has been used to study of molecular association of piperidinoethyl alkoxyphenylcarbamates. The self-association of this type of compounds has been studied with methyl phenylcarbamate as a simple model. The PCILO calculations indicate the open dimer with N-H...O=C hydrogen bond to be the most stable complex. Moreover, the PCILO method has been used fro study of intermolecular hydrogen bonds formed between oxygen and nitrogen atoms of -NH-COO- group of the title compounds and N-methylacetamide, N,N-dimethylacetamide, and phenol. The calculations have shown that the most stable hydrogen bonds are formed by carbonyl oxygen atom. Somewhat weaker hydrogen bonds are formed by N-H group. The weakest hydrogen bonds are formed by methoxyl oxygen atom of the -NH-COO- part of the drug.

PCILO study of hydrogen bond and proton transfer in systems 1-methylthymine-acetamide and 1-methylthymine-acetic acid

1981 ◽  
Vol 46 (4) ◽  
pp. 957-962 ◽  
Author(s):  
Milan Remko
Keyword(s):  
Hydrogen Bond ◽  
Acetic Acid ◽  
Hydrogen Bonds ◽  
Proton Transfer ◽  
Quantum Chemical ◽  
Potential Functions ◽  
Double Proton Transfer ◽  
Proton Potential ◽  
Pcilo Method

Complexes containing two hydrogen bonds of the systems 1-methylthymine-acetamide and 1-methylthymine-acetic acid have been studied by the quantum-chemical PCILO method. In accordance with experiment our PCILO calculations have shown that acetic acid forms stronger hydrogen bonds than acetamide with 1-methylthymine. Further the PCILO method has been used to study of double proton transfer in O-H...O and N-H...O bonds of the complexes 1-methylthymine-acetamide and 1-methylthymine-acetic acid. Using equilibrium O...O and N...O distances, the PCILO calculations have given one-minimum proton potential functions. The proton transfer has not been observed. At somewhat longer N...O and O...O distances (0.30 nm) the PCILO calculations indicate a second minimum as a shoulder.

Hydrogen bonds and proton transfer in imidazole oligomers and (imidazole)2H(+) system: quantum-chemical calculations

1980 ◽  
Vol 45 (12) ◽  
pp. 3482-3487 ◽  
Author(s):  
Milan Remko
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Proton Transfer ◽  
Quantum Chemical ◽  
Equilibrium Distance ◽  
Hydrogen Bond Energy ◽  
Proton Potential ◽  
Pcilo Method ◽  
System Quantum ◽  
Semi Empirical

The semi-empirical PCILO method has been applied to study of hydrogen bonds and proton transfer in linear n-mers of imidazole (n = 3). The calculated hydrogen bond energy in the dimer is 30.64 kJ mol-1. In imidazole trimer interaction energy of the "second" hydrogen bond increased to 32.02 kJ mol-1. One-minimum functions only have been found by calculations of the proton potential functions in imidazole dimer and trimer for the equilibrium distances RN...N. For somewhat longer distances RN...N = 0.30 nm a second minimum was observed as shoulder. On the contrary, for the (imidazole)2H(+) system the proton potential curve has two minima for the equilibrium distance RN...N = 0.252 nm, the second minimum is more stable by 3.97 kJ mol-1.

scholarly journals Orthogonal halogen and hydrogen bonds involving a peptide bond model

CrystEngComm ◽  
2014 ◽  
Vol 16 (35) ◽  
pp. 8102-8105 ◽  
Author(s):  
Vera Vasylyeva ◽  
Susanta K. Nayak ◽  
Giancarlo Terraneo ◽  
Gabriella Cavallo ◽  
Pierangelo Metrangolo ◽  
...  
Keyword(s):  
Hydrogen Bonds ◽  
Oxygen Atom ◽  
Peptide Bond ◽  
Carbonyl Oxygen ◽  
Carbonyl Oxygen Atom ◽  
Halogen Bonds ◽  
Bond Model

N-Methylacetamide, a well-known peptide bond model, and dihalotetrafluorobenzenes form co-crystals and show geometrically orthogonal hydrogen and halogen bonds sharing the same carbonyl oxygen atom.

Copper(II) and cobalt(II) hydroxypyridinecarboxylates: Synthesis, crystal structures, spectral and magnetic properties

2008 ◽  
Vol 62 (5) ◽  
Author(s):  
Jozef Miklovič ◽  
Peter Segľa ◽  
Dušan Mikloš ◽  
Ján Titiš ◽  
Radovan Herchel ◽  
...  
Keyword(s):  
Hydrogen Bonds ◽  
Oxygen Atom ◽  
Crystal Structures ◽  
Magnetic Measurements ◽  
Crystal Structure Analysis ◽  
Amide Group ◽  
Carboxyl Group ◽  
Intermolecular Hydrogen Bonds ◽  
Single Crystal Structure Analysis

AbstractSynthesis and characterization of six copper(II) and cobalt(II) octahedral complexes [M(6-OHpic)2(H2O)2] (6-OHpic is 6-hydroxypicolinato), [M(2-OHnic)2(H2O)2] (2-OHnic is 2-hydroxynicotinato), [Cu(6-OHnic)2(H2O)2] (6-OHnic is 6-hydroxynicotinato) as well as [Co(H2O)6](6-OHnic)2 are reported. Their characterization was carried out using elemental analysis, infrared, and magnetic measurements. Based on IR spectra, N,O-coordination of 6-OHpic (via the oxygen atom of the carboxyl group and the nitrogen atom of the pyridine ring), O,O-asymmetrically chelating coordination of the carboxyl groups as well as ionic coordination of 6-OHnic and chelating O,O-coordination (through the oxygen atom of the carboxyl group and the oxygen atom of the amide group) of keto(amide) tautomer of 2-OHnic were supposed. Moreover, crystal structures of 2-OHnicH and the complex [Co(2-OHnic)2(H2O)2]) were determined by X-ray single crystal structure analysis. The system of hydrogen bonds predominantly stabilizes the keto(amide) tautomer of both 2-hydroxynicotinic acid and 2-OHnic anion in the cobalt(II) complex. Intermolecular hydrogen bonds (between the oxygen atom of the amide group and the hydrogen atom of the NH group) interconnect two neighbouring molecules of 2-OHnicH forming dimers. Cobalt(II) in complex [Co(2-OHnic)2(H2O)2] has nearly a regular compressed tetragonal bipyramidal arrangement.

Comparing the strength of covalent bonds, intermolecular hydrogen bonds and other intermolecular interactions for organic molecules: X-ray diffraction data and quantum chemical calculations

2016 ◽  
Vol 40 (8) ◽  
pp. 6848-6853 ◽  
Author(s):  
Angelo Gavezzotti
Keyword(s):  
Hydrogen Bonds ◽  
Diffraction Data ◽  
Chemical Bonding ◽  
Quantum Chemical ◽  
Organic Molecules ◽  
X Ray Diffraction ◽  
Intermolecular Hydrogen Bonds ◽  
Covalent Bonds ◽  
X Ray ◽  
Different Types

The chemical bonding landscape for organic molecules clearly demonstrates the different ranges of stability and predictability for the different types of interactions.

Structure of the 2-Pyrrolidinone Monohydrate

1999 ◽  
Vol 54 (12) ◽  
pp. 1598-1601 ◽  
Author(s):  
Päivi Pirilä ◽  
Ilpo Mutikainen ◽  
Jouni Pursiainen
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Oxygen Atom ◽  
Water Molecule ◽  
Carbonyl Oxygen ◽  
Carbonyl Oxygen Atom ◽  
Water Molecules ◽  
X Ray

The X-ray crystal structure of the 1:1 adduct shows a complicated network of water and 2-pyrrolidinone molecules where the carbonyl oxygen atom of 2-pyrrolidinone forms hydrogen bonds with protons of two separate water molecules and the NH proton of the 2- pyrrolidinone molecule interacts with the oxygen atom of a third water molecule.

scholarly journals Secondary structure of hyaluronate in solution. A 1H-n.m.r. investigation at 300 and 500 MHz in [2H6]dimethyl sulphoxide solution

1984 ◽  
Vol 220 (1) ◽  
pp. 197-205 ◽  
Author(s):  
J E Scott ◽  
F Heatley ◽  
W E Hull
Keyword(s):  
Secondary Structure ◽  
Hydrogen Bonds ◽  
Oxygen Atom ◽  
Glucuronic Acid ◽  
Chondroitin Sulphate ◽  
Chemical Shifts ◽  
Heparan Sulphate ◽  
Carbonyl Oxygen ◽  
Dimethyl Sulphoxide ◽  
Coupling Constants

The 1H-n.m.r. spectra of solutions in [2H6]dimethyl sulphoxide of the sodium salts of tetra-, hexa- and octa-saccharides prepared from hyaluronate by testicular-hyaluronidase digestion were examined at 300 and 500 MHz. The signals from hydroxy groups at positions 2 and 3 in the glucuronic acid moiety were assigned. Their chemical shifts and associated temperature-dependencies, as well as their coupling constants, depended on whether or not the uronic acid was at the non-reducing end. Deviations from the ‘normal’ pattern of hydroxy-group proton n.m.r. behaviour were attributable to participation in hydrogen bonds, either to the acetamido carbonyl oxygen atom or the pyranose ring oxygen atom of neighbouring N-acetylhexosamine moieties. A secondary structure, containing four different hydrogen bonds per trisaccharide unit of glucuronsyl-hexosaminyl-glucuronic acid, was demonstrated. This is the first complete and detailed secondary structure to be established for hyaluronate in any solvent. Hyaluronate is compared with chondroitin sulphate, dermatan sulphate, heparan sulphate and keratan sulphate in their potential to form secondary structures with features in common. The significance of the details of the structure to its overall stability, and the probability of their persistence into aqueous environments, are discussed. The presence of all or most of the secondary structure in glycosaminoglycuronans is correlated with a space-filling function in the tissue, and with a high carbohydrate content in the parent proteoglycan in the case of the chondroitin sulphates.

A quantum-chemical study of phenol self-association of open and cyclic dimers and trimers

1984 ◽  
Vol 49 (4) ◽  
pp. 759-763 ◽  
Author(s):  
Milan Remko
Keyword(s):  
Hydrogen Bond ◽  
Quantum Chemical ◽  
Quantum Chemical Study ◽  
Chemical Study ◽  
Positive Cooperativity ◽  
Pcilo Method ◽  
Self Association

Itermolecular hydrogen bond in the open/linear and cyclic/closed dimers and trimers of phenol has been studied by means of the quantum-chemical PCILO method. Our calculations have shown that the open /linear associate is more stable in the case of the dimers. On the contrary, the cyclic/closed associate is more stable in the case of the trimers. Positive cooperativity has been observed by formation of both the open/linear and cyclic/closed trimers

Quantum-chemical study of N-methylacetamide and N,N-dimethylacetamide as models for peptidic bond in hydrogen-bond interaction with water, methanol and phenol

1983 ◽  
Vol 48 (11) ◽  
pp. 3214-3222 ◽  
Author(s):  
Milan Remko ◽  
Ivan Sekerka ◽  
Vladimír Frecer
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Quantum Chemical ◽  
Quantum Chemical Study ◽  
Geometry Optimization ◽  
Chemical Study ◽  
Hydrogen Bond Interaction ◽  
Proton Donors ◽  
Pcilo Method ◽  
Peptide Hydrogen

The PCILO quantum-chemical method with geometry optimization has been used to study rotation barriers of methyl groups in N-methylacetamide and N,N-dimethylacetamide. In all the cases studied, the eclipsed conformation have been found to be the most stable. Cis form of N-methylacetamide is less stable than the corresponding trans form by 2.0 kJ mol-1. Moreover, the PCILO method has been used to study linear n-mers (n = 4) of N-methylacetamide. On going from the dimer to tri- and tetramers, the hydrogen-bond energies have been found non-additive, and positive cooperativity has been observed. Finally, hydrogen-bond complexes have been studied which were formed by C=O groups of N-methylacetamide and N,N-dimethylacetamide with water, methanol or phenol as proton-donors. The said proton-donors have been found to act as breakers of inter-peptide hydrogen bonds N-H...O=C. The hydrogen bonds formed by methanol are somewhat stronger than those formed by water. In accordance with experiment, the strongest hydrogen bonds with the studied proton-acceptors are formed by phenol.

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