A Theoretical Study of the Site of Protonation of Formamide Using Non-empirical LCAO-MO-SCF Calculations

1973 ◽  
Vol 51 (9) ◽  
pp. 1432-1434 ◽  
Author(s):  
Alan C. Hopkinson ◽  
Imre G. Csizmadia
Keyword(s):  
Proton Affinity ◽  
Molecular Orbital ◽  
Theoretical Study ◽  
Molecular Orbital Calculations ◽  
Scf Calculations ◽  
Lcao Mo

Molecular orbital calculations are used to show that O-protonated formamide is more stable than its N-protonated tautomer by 6.2 kcal/mol. The computed proton affinity of formamide (assuming O-protonation) is computed to be 254.8 kcal/mol.

Molecular orbital calculations for sulphur-nitrogen heterocycles. I. The 3-hydroxyisothiazole system

1968 ◽  
Vol 21 (5) ◽  
pp. 1113 ◽  
Author(s):  
JR Christie ◽  
B Selinger
Keyword(s):  
Molecular Orbital ◽  
Perturbation Analysis ◽  
Related Species ◽  
Nitrogen Heterocycles ◽  
Chemical Properties ◽  
Molecular Orbital Calculations ◽  
Semi Empirical ◽  
Scf Calculations

LCAO-SCF calculations of various types have been performed for 3-hydroxy-isothiazole and related species. A perturbation analysis has shown that the values assigned to some of the semi-empirical parameters affect the results to a greater extent than has been supposed. Some of the chemical properties can be rationalized on the basis of these calculations.

A theoretical study of the structures and stabilities of C2H3S+ ions

1987 ◽  
Vol 65 (6) ◽  
pp. 1209-1213 ◽  
Author(s):  
Christopher F. Rodriquez ◽  
Alan C. Hopkinson
Keyword(s):  
Experimental Observation ◽  
Molecular Orbital ◽  
Global Minimum ◽  
Theoretical Study ◽  
Saddle Points ◽  
Intramolecular Rearrangement ◽  
Molecular Orbital Calculations ◽  
Dissociation Channel ◽  
Transition Structures

Abinitio molecular orbital calculations at the 6-31G* level have been used to locate eight minima and five saddle points on the C2H3S+ hypersurface. The thioacetyl ion, H3CCS+ (1), is the global minimum and the 1-thiovinyl cation (4), 106 kJ mol−1 higher, is the next lowest. Interconversion of 1 and 4 has the highest barrier calculated for this surface (250 kJ mol−1 above 4) but all transition structures to intramolecular rearrangement are lower than the energies of the dissociation products. These results are consistent with the experimental observation that there is only one dissociation channel for ions C2H3S+, regardless of the structure of organosulphur compound from which C2H3S+ was produced. Comparisons are made with the C2H3O+ hypersurface.

A theoretical study on storage states of Li ions in carbon anodes of Li ion batteries using molecular orbital calculations

Carbon ◽  
2003 ◽  
Vol 41 (10) ◽  
pp. 1933-1939 ◽  
Author(s):  
Tetsuo Suzuki ◽  
Takahiro Hasegawa ◽  
Shin R. Mukai ◽  
Hajime Tamon
Keyword(s):  
Molecular Orbital ◽  
Theoretical Study ◽  
Molecular Orbital Calculations ◽  
Li Ion Batteries ◽  
Li Ion ◽  
Carbon Anodes

Theoretical Study on the Proton Affinity of Small Molecules Using Gaussian Basis Sets in the LCAO–MO–SCF Framework

1968 ◽  
Vol 49 (8) ◽  
pp. 3596-3601 ◽  
Author(s):  
A. C. Hopkinson ◽  
N. K. Holbrook ◽  
K. Yates ◽  
I. G. Csizmadia
Keyword(s):  
Small Molecules ◽  
Proton Affinity ◽  
Theoretical Study ◽  
Basis Sets ◽  
Gaussian Basis Sets ◽  
Lcao Mo

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).

Understanding Metal-Free Catalytic Hydrogenation: A Systematic Theoretical Study of the Hydrogenation of Ethene

2004 ◽  
Vol 57 (7) ◽  
pp. 659 ◽  
Author(s):  
Bun Chan ◽  
Leo Radom
Keyword(s):  
Catalytic Activity ◽  
Ab Initio ◽  
Proton Affinity ◽  
Molecular Orbital ◽  
Catalytic Hydrogenation ◽  
Theoretical Study ◽  
Molecular Orbital Theory ◽  
Orbital Theory ◽  
Metal Free ◽  
High Level

Metal-free catalytic hydrogenation of ethene has been examined using high-level [G3(MP2)-RAD] ab initio molecular orbital theory. The dependence of the catalytic activity on the nature of the catalyst Z–X–H has been explored. We find that the catalytic activity is generally greater as Z–X–H becomes more acidic, both for first- and second-row atoms X. Molecules in which X is a second-row atom generally lead to more effective catalysis than the corresponding first-row analogues. The proton affinity at X of Z–X–H also contributes significantly to the catalysis in some cases (e.g. amines).

A theoretical study of the Curtius rearrangement. The electronic structures and interconversions of the CHNO species

1977 ◽  
Vol 55 (9) ◽  
pp. 1498-1510 ◽  
Author(s):  
Arvi Rauk ◽  
Paul F. Alewood
Keyword(s):  
Electronic Structures ◽  
Theoretical Study ◽  
Electronic States ◽  
Decomposition Products ◽  
Curtius Rearrangement ◽  
Nitrile Oxides ◽  
Photochemical Decomposition ◽  
Degenerate States ◽  
Scf Calculations ◽  
Lcao Mo

The thermal and photochemical decomposition of formyl azide in the Curtius rearrangement has been studied by means of RHF–LCAO–MO–SCF calculations augmented by CI. The lower electronic states of carbonyl azides, carbonyl nitrenes, isocyanates, cyanates, oxazirenes, nitrile oxides (fulminates), and isofulminates are discussed on the basis of the results for formyl azide and the corresponding isomers of formula CHNO. The discovery of two nearly degenerate states of A′′ symmetry for formyl azide which may channel decomposition products directly to both isocyanates and carbonyl nitrenes explains some puzzling features of the photolytic Curtius rearrangement. The interconvertibility of the CHNO isomers (and the RCNO isomers) is discussed in terms of the energetics and intended correlations of the accessible electronic states of these species.

Interactions between Methylene Blue and Pullulan According to Molecular Orbital Calculations

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
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