Energy parameters in polypeptides. V. Empirical hydrogen bond potential function based on molecular orbital calculations

1972 ◽  
Vol 76 (3) ◽  
pp. 375-393 ◽  
Author(s):  
R. F. McGuire ◽  
F. A. Momany ◽  
H. A. Scheraga
Keyword(s):  
Hydrogen Bond ◽  
Potential Function ◽  
Molecular Orbital ◽  
Molecular Orbital Calculations ◽  
Energy Parameters

Hydrogen-Bond-Like Nature of the CH/π Interaction as Evidenced by Crystallographic Database Analyses and Ab Initio Molecular Orbital Calculations

2001 ◽  
Vol 74 (12) ◽  
pp. 2421-2430 ◽  
Author(s):  
Osamu Takahashi ◽  
Yuji Kohno ◽  
Sachiyo Iwasaki ◽  
Ko Saito ◽  
Michio Iwaoka ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Ab Initio ◽  
Molecular Orbital ◽  
Molecular Orbital Calculations

Effect of Intermolecular Hydrogen Bonding on the Nuclear Quadrupole Interaction in Imidazole and its Derivatives as Studied by ab initio Molecular Orbital Calculations

2000 ◽  
Vol 55 (1-2) ◽  
pp. 315-322
Author(s):  
Nobuo Nakamura ◽  
Hirotsugo Masui ◽  
Takahiro Ueda
Keyword(s):  
Hydrogen Bond ◽  
Ab Initio ◽  
Molecular Orbital ◽  
Quadrupole Interaction ◽  
Bond Distance ◽  
Nuclear Quadrupole Interaction ◽  
Basis Sets ◽  
Molecular Orbital Calculations ◽  
Imidazole Derivatives ◽  
Nuclear Quadrupole

Ab initio Hartree-Fock molecular orbital calculations were applied to the crystalline imidazole and its derivatives in order to examine systematically the effect of possible N-H---N type hydrogen bond-ing on the nuclear quadrupole interaction parameters in these materials. The nitrogen quadrupole coupling constant (QCC) and the asymmetry parameter (η) of the electric field gradient (EFG) were found to depend strongly on the size of the molecular clusters, from single molecule, to dimer, trimer and to the infinite molecular chain, i.e., crystalline state, implying that the intermolecular N-H -N hydrogen bond affects significantly the electronic structure of imidazole molecule. A certain correla-tion between the QCC of 14N and the N-H bond distance R was also found and interpreted on the basis of the molecular orbital theory. However, we found that the value of the calculated EFG at the hy-drogen position of the N-H group, or the corresponding QCC value of 2 H, increases drastically as R-3 when R is shorter than about 0.1 nm, due probably to the inapplicability of the Gaussian basis sets to the very short chemical bond as revealed in the actual imidazole derivatives. We suggested that the ob-served N-H distances in imidazole derivatives should be re-examined.

A theoretical study of adduct formation between methanolate and Propan-2-one

1981 ◽  
Vol 34 (6) ◽  
pp. 1189 ◽  
Author(s):  
JC Sheldon
Keyword(s):  
Hydrogen Bond ◽  
Oxygen Atom ◽  
Ab Initio ◽  
Molecular Orbital ◽  
Theoretical Study ◽  
Adduct Formation ◽  
Molecular Orbital Calculations ◽  
Carbonyl Carbon ◽  
Methyl Group ◽  
Methoxide Anion

Ab initio molecular orbital calculations at the STO-3G level of approximation predict that the methoxide anion bonds through its oxygen atom to form complexes with acetone in at least three different ways: (i) A tetrahedral adduct at the carbonyl carbon (ΔE -262 kJ mol-1). (ii) A hydrogen-bond complex with a single hydrogen of one methyl group (- 100 kJ mol-1). (iii) A symmetrical bidentate hydrogen-bond complex with a hydrogen from each acetone methyl group (- 143 kJ mol-1).

The Interaction of Magnesium Cyclen Complex with Water

1987 ◽  
Vol 42 (8) ◽  
pp. 871-874 ◽  
Author(s):  
Vithaya W. Ruangpornvisuti ◽  
Michael M. Probst ◽  
Bernd M. Rode
Keyword(s):  
Ab Initio ◽  
Potential Function ◽  
Molecular Orbital ◽  
Energy Surface ◽  
Intermolecular Potential ◽  
Molecular Orbital Calculations ◽  
Interaction Function ◽  
Calculated Energy

An intermolecular potential function for the magnesium complex of 1,4,7,10-tetraazacyclododecane (cyclen) and water has been derived from ab initio molecular orbital calculations. The form of this interaction function is obtained by fitting 250 points of the calculated energy surface.

The Conformation of β-Pseudouridine about the Glycosidic Bond as Studied by 1H Homonuclear Overhauser Measurements and Molecular Orbital Calculations

1974 ◽  
Vol 52 (3) ◽  
pp. 371-375 ◽  
Author(s):  
R. K. Nanda ◽  
R. Tewari ◽  
G. Govil ◽  
Ian C. P. Smith
Keyword(s):  
Hydrogen Bond ◽  
Molecular Orbital ◽  
Nuclear Overhauser Effect ◽  
Glycosidic Bond ◽  
Molecular Orbital Calculations ◽  
Overhauser Effect ◽  
Rapid Equilibrium ◽  
Nuclear Overhauser ◽  
Cndo Calculations

The conformation of β-pseudouridine about the glycosidic bond has been studied by both the internal nuclear Overhauser effect and CNDO molecular orbital calculations. Both syn and anti conformations are found to exist in rapid equilibrium, with roughly equal populations of each. The proportion of syn to anti conformations does not change significantly with pD over the range 7.1 to 11.6. The CNDO calculations suggest that the syn conformation is stabilized by formation of a hydrogen bond, C4=O … O—H5′, but the n.m.r. data indicate that if such a bond exists its probability is the same at pD 7.1 and 11.6. Major contributions to n.O.e. may occur through conformations other than those which are most stable.

Amino and cyano N atoms in competitive situations: which is the best hydrogen-bond acceptor? A crystallographic database investigation

2001 ◽  
Vol 57 (6) ◽  
pp. 850-858 ◽  
Author(s):  
Nahossé Ziao ◽  
Jérôme Graton ◽  
Christian Laurence ◽  
Jean-Yves Le Questel
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Ab Initio ◽  
Molecular Orbital ◽  
Amino Nitrogen ◽  
Lone Pair ◽  
Molecular Surface ◽  
Molecular Orbital Calculations ◽  
Hydrogen Bond Acceptor

The relative hydrogen-bond acceptor abilities of amino and cyano N atoms have been investigated using data retrieved from the Cambridge Structural Database and via ab initio molecular orbital calculations. Surveys of the CSD for hydrogen bonds between HX (X = N, O) donors, N—T—C≡N (push–pull nitriles) and N—(Csp 3) n —C≡N molecular fragments  show that the hydrogen bonds are more abundant on the nitrile than on the amino nitrogen. In the push–pull family, in which T is a transmitter of resonance effects, the hydrogen-bonding ability of the cyano nitrogen is increased by conjugative interactions between the lone pair of the amino substituent and the C≡N group: a clear example of resonance-assisted hydrogen bonding. The strength of the hydrogen-bonds on the cyano nitrogen in this family follows the experimental order of hydrogen-bond basicity, as observed in solution through the pK HB scale. The number of hydrogen bonds established on the amino nitrogen is greater for aliphatic aminonitriles N—(Csp 3) n —C≡N, but remains low. This behaviour reflects the greater sensitivity of the amino nitrogen to steric hindrance and the electron-withdrawing inductive effect compared with the cyano nitrogen. Ab initio molecular orbital calculations (B3LYP/6-31+G** level) of electrostatic potentials on the molecular surface around each nitrogen confirm the experimental observations.

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