Quantum-chemical study of active centers of cationic polymerization of olefins in the presence of aluminum halide complexes with proton-donors

1992 ◽  
Vol 28 (1) ◽  
pp. 11-18
Author(s):  
K. S. Minsker ◽  
V. A. Babkin
Keyword(s):  
Cationic Polymerization ◽  
Quantum Chemical ◽  
Quantum Chemical Study ◽  
Chemical Study ◽  
Active Centers ◽  
Proton Donors ◽  
Aluminum Halide ◽  
Halide Complexes

A quantum chemical study of butene reactions on molybdate catalysts

1980 ◽  
Vol 45 (10) ◽  
pp. 2589-2604 ◽  
Author(s):  
Stanislav Beran ◽  
Pavel Jírů ◽  
Blanka Wichterlová
Keyword(s):  
Double Bond ◽  
Oxidation State ◽  
Metal Atom ◽  
Electron Acceptor ◽  
Quantum Chemical ◽  
Quantum Chemical Study ◽  
Chemical Study ◽  
Active Centers ◽  
Double Bond Isomerization ◽  
Adsorption Complexes

Both the EHT and IEHT methods were used in the study of interaction of various butene forms with models of catalytic active centers (Mo-O-metal), in which the Mo atom is in its +4 or +6 oxidation state and is tetrahedrally or octahedrally coordinated. The influence of an additional metal atom incorporated in the molybdate lattice was also studied. The results suggest that the interaction of all butene forms with the studied models of catalytic surface centers leads to the formation of stable adsorption complexes and that the butene molecule thus chemisorbed can undergo a direct cis-trans or a double-bond isomerization. It is shown that the probability of occurrence of both these reactions depends strongly on the symmetry of the surface center of the catalyst, on the valence of the Mo atom, and increases with the electron acceptor capability of the additional metal.

Quantum-chemical study of N-methylacetamide and N,N-dimethylacetamide as models for peptidic bond in hydrogen-bond interaction with water, methanol and phenol

1983 ◽  
Vol 48 (11) ◽  
pp. 3214-3222 ◽  
Author(s):  
Milan Remko ◽  
Ivan Sekerka ◽  
Vladimír Frecer
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Quantum Chemical ◽  
Quantum Chemical Study ◽  
Geometry Optimization ◽  
Chemical Study ◽  
Hydrogen Bond Interaction ◽  
Proton Donors ◽  
Pcilo Method ◽  
Peptide Hydrogen

The PCILO quantum-chemical method with geometry optimization has been used to study rotation barriers of methyl groups in N-methylacetamide and N,N-dimethylacetamide. In all the cases studied, the eclipsed conformation have been found to be the most stable. Cis form of N-methylacetamide is less stable than the corresponding trans form by 2.0 kJ mol-1. Moreover, the PCILO method has been used to study linear n-mers (n = 4) of N-methylacetamide. On going from the dimer to tri- and tetramers, the hydrogen-bond energies have been found non-additive, and positive cooperativity has been observed. Finally, hydrogen-bond complexes have been studied which were formed by C=O groups of N-methylacetamide and N,N-dimethylacetamide with water, methanol or phenol as proton-donors. The said proton-donors have been found to act as breakers of inter-peptide hydrogen bonds N-H...O=C. The hydrogen bonds formed by methanol are somewhat stronger than those formed by water. In accordance with experiment, the strongest hydrogen bonds with the studied proton-acceptors are formed by phenol.

A quantum chemical study of the acidity of acetylene and 1,2-dihydrobuckminsterfullerene de-rivatives

2018 ◽  
Vol 59 (1) ◽  
pp. 51-53
Author(s):  
M. V. Makarova ◽  
◽  
S. G. Semenov ◽  
R. R. Kostikov ◽  
◽  
...  
Keyword(s):  
Quantum Chemical ◽  
Quantum Chemical Study ◽  
Chemical Study
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