Maximal orbital analysis of molecular wavefunctions

2018 ◽  
Vol 40 (1) ◽  
pp. 39-50
Author(s):  
Michel Dupuis ◽  
Meghana Nallapu
Keyword(s):  
Molecular Wavefunctions ◽  
Orbital Analysis

Effect of the intramolecular hydrogen bond in the active metabolite analogs of leflunomide for blocking the Plasmodium falciparum dihydroorotate dehydrogenase enzyme: QTAIM, NBO, and docking study

2020 ◽  
Vol 16 ◽  
Author(s):  
Reihaneh Heidarian ◽  
Mansoureh Zahedi-Tabrizi
Keyword(s):  
Hydrogen Bond ◽  
Plasmodium Falciparum ◽  
Molecular Orbital ◽  
Intramolecular Hydrogen Bond ◽  
Active Metabolite ◽  
Chemical Hardness ◽  
Dihydroorotate Dehydrogenase ◽  
Molecular Orbital Analysis ◽  
Intramolecular Hydrogen ◽  
Orbital Analysis

: Leflunomide (LFM) and its active metabolite, teriflunomide (TFM), have drawn a lot of attention for their anticancer activities, treatment of rheumatoid arthritis and malaria due to their capability to inhibit dihydroorotate dehydrogenase (DHODH) and Plasmodium falciparum dihydroorotate dehydrogenase (PfDHODH) enzyme. In this investigation, the strength of intramolecular hydrogen bond (IHB) in five analogs of TFM (ATFM) has been analyzed employing density functional theory (DFT) using B3LYP/6-311++G (d, p) level and molecular orbital analysis in the gas phase and water solution. A detailed electronic structure study has been performed using the quantum theory of atoms in molecules (QTAIM) and the hydrogen bond energies (EHB) of stable conformer obtained in the range of 76-97 kJ/mol, as a medium hydrogen bond. The effect of substitution on the IHB nature has been studied by natural bond orbital analysis (NBO). 1H NMR calculations show an upward trend in the proton chemical shift of the enolic proton in the chelated ring (14.5 to 15.7ppm) by increasing the IHB strength. All the calculations confirmed the strongest IHB in 5-F-ATFM and the weakest IHB in 2-F-ATFM. Molecular orbital analysis, including the HOMO-LUMO gap and chemical hardness, was performed to compare the reactivity of inhibitors. Finally, molecular docking analysis was carried out to identify the potency of inhibition of these compounds against PfDHODH enzyme.

Frozen-Orbital Analysis of the Excited States of Metal Complexes in High Symmetry: OhCase

1996 ◽  
Vol 100 (39) ◽  
pp. 15753-15759 ◽  
Author(s):  
Hiromi Nakai ◽  
Hiroshi Morita ◽  
Hiroshi Nakatsuji
Keyword(s):  
Metal Complexes ◽  
Excited States ◽  
High Symmetry ◽  
Orbital Analysis

Magnetism and structure of a novel trinuclear cluster compound of divalent copper

1969 ◽  
Vol 22 (12) ◽  
pp. 2527 ◽  
Author(s):  
R Beckett ◽  
R Colton ◽  
BF Hoskins ◽  
RL Martin ◽  
DG Vince
Keyword(s):  
Structural Data ◽  
Hydroxyl Group ◽  
Cluster Compound ◽  
X Ray Diffraction ◽  
Trinuclear Cluster ◽  
Metal Atoms ◽  
Doublet Ground State ◽  
Molecular Orbital Analysis ◽  
Orbital Analysis ◽  
Unusual Type

The magnetic properties of a series of salts of the type [Cu3L3OH]2+ (where HL is pyridine-2-aldehyde oxime and L is the deprotonated ligand) have been examined. All of the compounds showed a magnetic moment of 1.00 B.M. per copper atom over a wide temperature range which suggests that the cation contains a trinuclear cluster of interacting copper atoms. The crystal structure of Cu3L3OH(SO4),xH2O has been determined by single- crystal X-ray diffraction techniques and confirms that the complex does indeed contain an unusual type of trinuclear cluster of metal atoms. The three copper atoms form an equilateral triangle and the sulphato group exhibits a highly novel ?tripod? bridging function to the Cu3 triangle. On the other side of the triangle, the hydroxyl group also bridges to all the metal atoms. A qualitative molecular orbital analysis not only suggests that the hydroxyl group is involved in four-centre bonding with the Cu3 triads, but also highlights its role in reducing the spin of the trimer so that only a doublet ground state is populated between 80-300�K. However, the alternative super-exchange mechanism cannot be ruled out by the magnetic and structural data.

Substituent effect on N–H bond dissociation enthalpies of carbamates: a theoretical study

2015 ◽  
Vol 93 (3) ◽  
pp. 279-288 ◽  
Author(s):  
Rupinder preet Kaur ◽  
Damanjit Kaur ◽  
Ritika Sharma
Keyword(s):  
Substituent Effect ◽  
Density Functional ◽  
Theoretical Study ◽  
Natural Bond Orbital ◽  
Stabilization Energy ◽  
Isodesmic Reactions ◽  
Bond Dissociation ◽  
Density Functional Methods ◽  
Functional Methods ◽  
Orbital Analysis

The present investigation deals with the study of the N–H bond dissociation enthalpies (BDEs) of the Y-substituted (NH2-C(=X)Y-R) and N-substituted ((R)(H)NC(=X)YH) carbamates (X, Y = O, S, Se; R = H, CH3, F, Cl, NH2), which have been evaluated using ab initio and density functional methods. The variations in N−H BDEs of these Y-substituted and N-substituted carbamates as the effect of substituent have been understood in terms of molecule stabilization energy (ME) and radical stabilization energy (RE), which have been calculated using the isodesmic reactions. The natural bond orbital analysis indicated that the electrodelocalization of the lone pairs of heteroatoms in the molecules and radicals affect the ME and RE values depending upon the type and site of substitution (whether N- or Y-). The variations in N−H BDEs depend upon the combined effect of molecule stabilization and radical stabilization by the various substituents.

UPS Study of [2,2] (2,5)Furanophane and [2,2] (2,5)Thiophenophane Evidence Regarding the Importance of Through Bond and Through Space Interactions

1978 ◽  
Vol 33 (8) ◽  
pp. 959-963 ◽  
Author(s):  
Fernando Bernardi ◽  
Andrea Bottoni ◽  
Francesco Paolo Colonna ◽  
Giuseppe Distefano ◽  
Ugo Folli ◽  
...  
Keyword(s):  
Molecular Orbital ◽  
Photoelectron Spectra ◽  
Molecular Orbital Analysis ◽  
Orbital Analysis

The ultraviolet photoelectron spectra of [2,2](2,5)furanophane (FUPH) and [2,2](2,5)thiophenophane (THPH) have been analyzed on the basis of a perturbational molecular orbital analysis, by comparison with CNDO/2 computations and by correlating them with the spectra of related molecules. Through space and through bond interactions between the two heteroaromatic rings are shown to be important in determining the ordering of the outermost MO’s in this class of compounds.

A discussion on orbital analysis - Determination of the Earth’s gravitational field from satellite orbits: methods and results

1967 ◽  
Vol 262 (1124) ◽  
pp. 119-134 ◽  
Keyword(s):  
Gravitational Field ◽  
Artificial Satellites ◽  
Satellite Orbits ◽  
Estimation Of Parameters ◽  
Earth’S Gravitational Field ◽  
Keplerian Ellipse ◽  
Orbital Data ◽  
Analysis Determination ◽  
Orbital Analysis

The structure of theories used in determining the gravitational field from the perturbations of orbits of artificial satellites is discussed and it is shown how it corresponds to the fact that small departures from a Keplerian ellipse are readily observed. Some current problems are mentioned. Statistical problems in the estimation of parameters of the field from orbital data are considered and recent estimates are summarized

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