ChemInform Abstract: INDO MOLECULAR ORBITAL CALCULATIONS OF THE DIPOLE MOMENT AND CONFORMATION OF METHYL FORMATE AND METHYL FLUOROFORMATE

δ-Carboline, together with β-carboline, has been synthesized in reasonably good yield by the Fischer cyclization of cyclohexanone 3-pyridylhydrazone followed by dehydrogenation of the separated tetrahydro derivatives. The isomer ratios of products formed in this and similar reactions are discussed. Nitration of δ-carboline gives a mixture of the 6- and 8-nitro derivatives, the latter being the predominant product. The magnitude of the dipole moment of δ-carboline is appreciably higher than that predicted from molecular orbital calculations (15).

Download Full-text

Long-range proton coupling constants and molecular orbital calculations as indicators of conformational populations of benzene-1,2- and -1,3-dicarbaldehydes

Canadian Journal of Chemistry ◽

10.1139/v86-027 ◽

1986 ◽

Vol 64 (1) ◽

pp. 158-163 ◽

Cited By ~ 5

Author(s):

Ted Schaefer ◽

Glenn H. Penner ◽

Rudy Sebastian ◽

Craig S. Takeuchi

Keyword(s):

Dipole Moment ◽

Carbon Tetrachloride ◽

Molecular Orbital ◽

Long Range ◽

Benzene Solution ◽

Geometry Optimization ◽

Coupling Constants ◽

Molecular Orbital Calculations ◽

Trans Form ◽

Nmr Studies

The 1H nmr spectra of the benzene-1,2- and -1,3-dicarbaldehydes in carbon tetrachloride, benzene-d6, and acetone-d6 solutions at 300 K are analyzed. The stereospecific long-range couplings over five formal bonds between the sidechain and ring protons show that the 1,2 isomer exists as an 87:13 mixture of the cis–trans and trans–trans conformers in carbon tetrachloride. These populations are insensitive to solvent. Molecular orbital calculations utilizing extensive geometry optimization procedures imply that the cis–cis form, with proximate C=O bonds, is indeed of negligible significance as assumed in obtaining the populations of the other forms. Further calculations define a pathway of relatively low energy for interconversion of the two abundant forms, in agreement with dynamic nmr studies. For the 1,3 isomer the long-range couplings provide a check of the conformer populations deduced from dipole moment and 13C nmr studies. For example, if the cis–trans form is 70% abundant, as deduced from the dipole moment in benzene solution, then the long-range couplings imply that the population of the cis–cis conformer is insignificant.

Download Full-text

Interactions between Methylene Blue and Pullulan According to Molecular Orbital Calculations

IEEJ Transactions on Fundamentals and Materials ◽

10.1541/ieejfms.140.529 ◽

2020 ◽

Vol 140 (11) ◽

pp. 529-533

Author(s):

Pasika Temeepresertkij ◽

Saranya Yenchit ◽

Michio Iwaoka ◽

Satoru Iwamori

Keyword(s):

Methylene Blue ◽

Molecular Orbital ◽

Molecular Orbital Calculations

Download Full-text

Electronic Properties for Medicine Inhibiting Cancer Metastasis (2) : Molecular Mechanics and Molecular Orbital Calculations for Urokinase

Journal of Computer Aided Chemistry ◽

10.2751/jcac.5.70 ◽

2004 ◽

Vol 5 ◽

pp. 70-78 ◽

Cited By ~ 3

Author(s):

Naoya Tsumura ◽

Fumitaka Sugiura ◽

Hiroshi Kobayashi ◽

Noriyuki Kurita

Keyword(s):

Electronic Properties ◽

Molecular Mechanics ◽

Molecular Orbital ◽

Cancer Metastasis ◽

Molecular Orbital Calculations

Download Full-text

Atomic and electronic structures of boron nitride nanohorns studied by high-resolution electron microscopy and molecular orbital calculations

Diamond and Related Materials ◽

10.1016/j.diamond.2004.12.050 ◽

2005 ◽

Vol 14 (3-7) ◽

pp. 1183-1189 ◽

Cited By ~ 11

Author(s):

Atsushi Nishiwaki ◽

Takeo Oku

Keyword(s):

Electron Microscopy ◽

High Resolution ◽

Boron Nitride ◽

Molecular Orbital ◽

Electronic Structures ◽

High Resolution Electron Microscopy ◽

Molecular Orbital Calculations ◽

Resolution Electron

Download Full-text

Proposal of novel natural inhibitors of severe acute respiratory syndrome coronavirus 2 main protease: Molecular docking and ab initio fragment molecular orbital calculations

Biophysical Chemistry ◽

10.1016/j.bpc.2021.106608 ◽

2021 ◽

Vol 275 ◽

pp. 106608

Author(s):

Divya Shaji ◽

Shohei Yamamoto ◽

Ryosuke Saito ◽

Ryo Suzuki ◽

Shunya Nakamura ◽

...

Keyword(s):

Molecular Docking ◽

Severe Acute Respiratory Syndrome ◽

Ab Initio ◽

Molecular Orbital ◽

Molecular Orbital Calculations ◽

Fragment Molecular Orbital ◽

Main Protease ◽

Natural Inhibitors

Download Full-text

A pairwise additivity scheme for conformational energies of substituted ethanes

Proceedings of the Royal Society of London Series A - Mathematical and Physical Sciences ◽

10.1098/rspa.1975.0048 ◽

1975 ◽

Vol 343 (1632) ◽

pp. 1-10 ◽

Cited By ~ 9

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.

Download Full-text