N,N-Linked biazoles. III. MNDO calculations on the conformation of N,N-linked biazoles and their quaternary salts

1984 ◽  
Vol 62 (4) ◽  
pp. 687-695 ◽  
Author(s):  
Maria Luisa Castellanos ◽  
Santiago Olivella ◽  
Nuria Roca ◽  
Javier De Mendoza ◽  
José Elguero
Keyword(s):  
Electronic Properties ◽  
Excellent Agreement ◽  
Theoretical Study ◽  
Dipole Moments ◽  
Mndo Method ◽  
Quaternary Salts ◽  
Mndo Calculations ◽  
Full Optimization ◽  
Experimental Values ◽  
Orthogonal Form

A theoretical study of fourteen N,N-linked biazoles has been carried out using the MNDO method with full optimization of the geometries. The variation of energy as a function of the conformation around the central N—N bond shows in all cases the higher stability of the orthogonal or near-orthogonal form. The contribution of the three main types of "ortho" interactions [Formula: see text] and the effect of quaternization have been evaluated. Of the electronic properties calculated, one must emphasize the excellent agreement of dipole moments with experimental values.

A study of structure of meta and para substituted phenyl and benzoyl isothiocyanates by the MNDO method

1987 ◽  
Vol 52 (9) ◽  
pp. 2115-2124 ◽  
Author(s):  
Ivan Danihel ◽  
Pavol Kristian ◽  
Stanislav Böhm ◽  
Josef Kuthan
Keyword(s):  
Electron Distribution ◽  
Dipole Moments ◽  
Point Of View ◽  
Mndo Method ◽  
Mndo Calculations ◽  
Non Linear ◽  
Benzoyl Isothiocyanates

On the basis of the optimized MNDO calculations of a selected series of meta and para substituted phenyl and benzoyl isothiocyanates it has been found that the –NCS group is non-linear in both the cases (the deviation from linearity is about 9°). For the phenyl isothiocyanates the values of CNC angles are in the region of 146.1° - 149.0°, and for the benzoyl isothiocyanates the respective regions for the CNC and OCN angles are 146.4° - 152.1° and 117.1° - 118.5°. In the meta substituted benzoyl isothiocyanates the –CONCS group is perpendicular to the phenyl residue. The results are discussed from the point of view of the electron distribution and dipole moments of the compounds studied.

scholarly journals A combined experimental and theoretical study on vibrational and electronic properties of (5-methoxy-1H-indol-1-yl)(5-methoxy-1H-indol-2-yl)methanone

2017 ◽  
Vol 15 (1) ◽  
pp. 238-246 ◽  
Author(s):  
Reem I. Al-Wabli ◽  
Munusamy Govindarajan ◽  
Maha S. Almutairi ◽  
Mohamed I. Attia
Keyword(s):  
Electronic Properties ◽  
Experimental Approach ◽  
Theoretical Study ◽  
Receptor Ligands ◽  
Mulliken Population ◽  
H Nmr ◽  
Experimental Values ◽  
Orbital Analysis ◽  
Good Agreement ◽  
C Nmr

Abstract(5-Methoxy-1H-indol-1-yl)(5-methoxy-1H-indol-2-yl)methanone (MIMIM) is a bis-indolic derivative that can be used as a precursor to a variety of melatonin receptor ligands. In this work, the energetic and spectroscopic profiles of MIMIM were studied by a combined DFT and experimental approach. The IR, Raman, UV-Vis, 1H NMR and 13C NMR spectra were calculated by PBEPBE and B3LYP methods, and compared with experimental ones. Results showed good agreement between theoretical and experimental values. Mulliken population and natural bond orbital analysis were also performed by time-dependent DFT approach to evaluate the electronic properties of the title molecule.

Structural, vibrational and electronic properties of α′-Ga2S3 under compression

2021 ◽  
Author(s):  
S. Gallego-Parra ◽  
R. Vilaplana ◽  
O. Gomis ◽  
E. Lora da Silva ◽  
A. Otero-de-la-Roza ◽  
...  
Keyword(s):  
Electronic Properties ◽  
Theoretical Study ◽  
Low Pressure ◽  
Electron Pairs ◽  
System P ◽  
Pressure Phase

We report a joint experimental and theoretical study of the low-pressure phase of α′-Ga2S3 under compression. The structural, vibrational, topological and electronic properties have been evaluated to reveal the relevance of the vacancy channels and the single and double lone electron pairs in the pressure behaviour of this system.

A Theoretical Study of Substituted Stepwise Fluorinated Cyclopropanone Keto-Enol System

2003 ◽  
Vol 58 (12) ◽  
pp. 749-755
Author(s):  
Abdullah El-Alali ◽  
Ali A. Marashdeh ◽  
Salim M. Khalil
Keyword(s):  
Theoretical Study ◽  
Dipole Moments ◽  
Heats Of Formation ◽  
Geometrical Parameters ◽  
Free Energies ◽  
Isodesmic Reactions ◽  
Orbital Energies ◽  
Substantial Concentration ◽  
Homo Lumo ◽  
Complete Optimization

MINDO-Forces calculations have been performed with complete optimization of the geometries on stepwise fluorinated cyclopropanones and their enols. Increase in the number of fluorine atoms causes destabilization of cyclopropanone. Perfluorinated enol was found to be present in substantial concentration, as was mentioned in previous work. This is supported by calculations of Gibbs free energies and isodesmic reactions. Geometrical parameters, heats of formation, electron densities, dipole moments and orbital energies (HOMO-LUMO) are reported.

Experimental and computed dipole moments in donor–bridge–acceptor systems with p-phenylene and p-carboranediyl bridges

2009 ◽  
Vol 74 (1) ◽  
pp. 131-146 ◽  
Author(s):  
Ladislav Drož ◽  
Mark A. Fox ◽  
Drahomír Hnyk ◽  
Paul J. Low ◽  
J. A. Hugh MacBride ◽  
...  
Keyword(s):  
Dipole Moment ◽  
Dipole Moments ◽  
Electronic Effects ◽  
Electronic Interactions ◽  
Donor And Acceptor ◽  
Homo And Lumo ◽  
Pull Systems ◽  
The Difference ◽  
Experimental Values ◽  
2D And 3D

Dipole moments were measured for a series of substituted benzenes, biphenyls, terphenyls, C-monoaryl- and C,C′-diaryl-p-carboranes. For the donor–bridge–acceptor systems, Me2N–X–NO2, where X is 1,4-phenylene, biphenyl-4,4′-diyl, terphenyl and 1,4-C6H4-p-CB10H10C-1,4-C6H4, the measured interaction dipole moments are 1.36, 0.74, 0.51 and 0.00 D, respectively. The magnitude of the dipole moment reflects the ability of the bridge to transmit electronic effects between donor and acceptor groups. Thus, whilst the 1,4-phenylene bridges allow moderate electronic interactions between the remote groups, the p-carboranediyl unit is less efficient as a conduit for electronic effects. Averaged dipole moments computed at the DFT (B3LYP/6-31G*) level of theory from two distinct molecular conformers are in good agreement with the experimental values. Examination of the calculated electronic structures provides insight into the nature of the interactions between the donor and acceptor moieties through these 2D and 3D aromatic bridges. The most significant cooperative effect of the bridge on the dipole moment occurs in systems where there is some overlap between the HOMO and LUMO orbitals. This orbital overlap criterion may help to define the difference between “push-pull” systems in which electronic effects are mediated by the bridging moiety, and simpler systems in which the bridge acts as an electronically innocent spacer unit and through-space charge transfer/separation is dominant.

The diverse electronic properties of C4N3monolayer under biaxial compressive strain: a theoretical study

2016 ◽  
Vol 49 (29) ◽  
pp. 295301 ◽  
Author(s):  
Haiping Wu ◽  
Yuzhen Liu ◽  
Erjun Kan ◽  
Yanming Ma ◽  
Wenjie Xu ◽  
...  
Keyword(s):  
Electronic Properties ◽  
Theoretical Study ◽  
Compressive Strain
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