Ab initio molecular orbital calculations of solvent clusters of trans-N-methylacetamide: structure, ring cluster formation and out-of-plane deformation

1996 ◽  
Vol 92 (6) ◽  
pp. 921 ◽  
Author(s):  
Ioannis N. Demetropoulos ◽  
Ioannis P. Gerothanassis ◽  
Constantina Vakka ◽  
Constantinos Kakavas
Keyword(s):  
Ab Initio ◽  
Molecular Orbital ◽  
Plane Deformation ◽  
Cluster Formation ◽  
Molecular Orbital Calculations ◽  
Out Of Plane ◽  
Solvent Clusters

scholarly journals Crystallographic and molecular-orbital studies on the geometry of antifolate drugs

1980 ◽  
Vol 187 (2) ◽  
pp. 533-536 ◽  
Author(s):  
W E Hunt ◽  
C H Schwalbe ◽  
K Bird ◽  
P D Mallinson
Keyword(s):  
Molecular Orbital ◽  
Plane Deformation ◽  
Carbonyl Oxygen ◽  
British Library ◽  
Molecular Orbital Calculations ◽  
Amino Groups ◽  
Binding Studies ◽  
Reductase Inhibitors ◽  
Out Of Plane ◽  
Bonding Properties

In the common dihydrofolate reductase inhibitors an amino substituent replaces the pteridine carbonyl oxygen atom of folates, with altered hydrogen-bonding properties and size. Flexibility in the amino groups could facilitate enzyme binding. Studies of cycloguanil hydrochloride by neutron diffraction show both in-plane and out-of-plane deformation of amino groups. Molecular-orbital calculations ab initio on 2,4-diamino-5-methylpyrimidinium cation confirm that the 4-amino group is readily deformable. The 2,4-diaminoquinazoline structure is reported. Atomic co-ordinates, thermal parameters, bond distances and bond angles for cycloguanil and 2,4-diaminoquinazoline have been deposited as Supplementary Publication SUP 50108 (13 pages) at the British Library Lending Division, Boston Spa. Wetherby, West Yorkshire LS23, 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1978) 169, 5.

A pairwise additivity scheme for conformational energies of substituted ethanes

1975 ◽  
Vol 343 (1632) ◽  
pp. 1-10 ◽  
Keyword(s):  
Large Deviations ◽  
Ab Initio ◽  
Dihedral Angle ◽  
Molecular Orbital ◽  
Methyl Groups ◽  
Molecular Orbital Calculations ◽  
Linear Combinations ◽  
Strongly Interacting ◽  
Conformational Energies

Ab initio molecular orbital calculations are used to explore additivity in the conformational energies of poly-substituted ethanes in terms of conformational energies of ethane and appropriate mono- and 1,2-di-substituted derivatives. Such relations would allow complex calculations for poly-substituted ethanes to be replaced by much simpler ones on a small number of parent molecules. General expressions for the linear combinations are derived from the assumption that interactions between vicinal substituents are pairwise additive and depend only on the vicinal dihedral angle. The additivity scheme is tested for 15 ethanes, di-, tri- or tetrasubstituted by cyano and methyl groups and for a smaller number of fluoroethanes. Additivity applies to within 0.1- 0.3 k J mol -1 in the methylethanes and mostly to within about 0.7- 0.8 kJ mol -1 in cyanoethanes. Large deviations are found among the geminally substituted fluoroethanes. It is suggested that the additivity approximation is most successful in the absence of strongly interacting geminal groups. Predictions are made of conformational energies of ten hexa(cyano- and methyl-) substituted ethanes.

Gas-Phase Tautomerism in the Triazoles and Tetrazoles: A Study by Photoelectron Spectroscopy and ab Initio Molecular Orbital Calculations

1981 ◽  
Vol 36 (11) ◽  
pp. 1246-1252 ◽  
Author(s):  
Michael H. Palmer ◽  
Isobel Simpson ◽  
J. Ross Wheeler
Keyword(s):  
Ab Initio ◽  
Gas Phase ◽  
Molecular Orbital ◽  
Photoelectron Spectroscopy ◽  
Relative Stability ◽  
Photoelectron Spectra ◽  
Equilibrium Geometry ◽  
Molecular Orbital Calculations ◽  
Methyl Derivatives

The photoelectron spectra of the tautomeric 1,2,3,- and 1,2,4-triazole and 1,2,3,4-tetrazole systems have been compared with the corresponding N-methyl derivatives. The dominant tautomers in the gas phase have been identified as 2 H-1,2,3-triazole, 1 H-1,2,4-triazole and 2H-tetrazole.Full optimisation of the equilibrium geometry by ab initio molecular orbital methods leads to the same conclusions, for relative stability of the tautomers in each of the triazoles, but the calculations wrongly predict the tetrazole tautomerism.

Prediction of Charge Transport Properties of Molecular Materials by Ab Initio Molecular Orbital Calculations

2000 ◽  
Vol 660 ◽  
Author(s):  
Wataru Sotoyama ◽  
Tomoaki Hayano ◽  
Hiroyuki Sato ◽  
Azuma Matsuura ◽  
Toshiaki Narusawa
Keyword(s):  
Charge Transport ◽  
Ab Initio ◽  
Molecular Orbital ◽  
Electron Mobility ◽  
Molecular Orbital Calculations ◽  
Molecular Materials ◽  
Structural Reorganization ◽  
Charge Hopping ◽  
Reorganization Energies ◽  
A Charge

ABSTRACTWe developed a method to predict the charge transport (CT) type (hole or electron) in molecular materials that uses molecular orbital calculations. The hole-and-electron-mobility ratios of molecular materials were calculated based on molecular structural reorganization energies in a charge hopping process. The CT types predicted from the calculated mobility ratios agreed with those experimentally obtained in seven of the eight model molecules.

scholarly journals Effect of BrU on the transition between wobble Gua-Thy and tautomeric Gua-Thy base-pairs: ab initio molecular orbital calculations

2013 ◽  
Vol 433 ◽  
pp. 012035
Author(s):  
Kazuya Nomura ◽  
Ryota Hoshino ◽  
Yasuhiro Hoshiba ◽  
Victor I Danilov ◽  
Noriyuki Kurita
Keyword(s):  
Ab Initio ◽  
Molecular Orbital ◽  
Molecular Orbital Calculations ◽  
Base Pairs
Sign in / Sign up

Export Citation Format

Share Document