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20 Years Anniversary of Molecular Topology at Cluj
September 25 - 30, 2006
Chemical Graph Theory | QSAR/QSPR | Nanoscience and Nanotechnology
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Contact us
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| Address: |
“Babes-Bolyai” University Faculty of Chemistry and Chemical Engineering Arany Janos Str. no. 11 RO-400028, Cluj Napoca
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| Phone: |
40-264-591998 40-264-593833 40-264-593877 40-264-593844
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| Fax: |
40-264-590818
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| E-mail: |
diudea@chem.ubbcluj.ro
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| Web: | TOPMOL 2006 |
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Webstats:
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Posters and Abstracts
Theoretical Study of Methyl Orange Structure by the PM3 Semiempirical Quantum Chemical Method
Methyl orange is known as pH indicator, being employed for titrating most mineral acids, strong bases and estimating alkalinity of waters.
In this study the structure of methyl orange was modelled by molecular mechanics using the MM2 force field and the PM3 quantum chemical method and compared to X-ray crystallographic data.
Several conformations were generated by molecular mechanics calculations and the low energy conformations thus obtained were further minimized by the semiempirical PM3 approach.
Bond lengths and angles of the minimum energy structures were then compared to the experimental X-ray crystallography structural data by statistical analysis.
Methyl orange structure obtained by the molecular mechanics calculations is in good agreement with the crystallographic data.
New method of finding the analytical solutions directly on the base on the reaction mechanism
An alternative method for solving homogenous and non-homogenous linear differential equation systems used in chemical kinetics and pharmacokinetics on the basis of flow graph principles has been proposed.
Classical method of solving these systems with flow graphs involves the employment of Laplace transform before depicting a flow graph and the inverse Laplace transform after using the Mason's rules. A short description of flow graph algebra has been presented. One model very often encountered in pharmacokinetics was solved. Our proposed method is simpler and more direct, eliminating the Laplace transforms. The calculus is made directly on the base of the flow graph representing the image of reaction scheme (pharmacokinetic model).
LOCALIZED VERSUS DELOCALIZED SURFACE ELECTRONS IN
BORANE / GERMANIUM CLUSTERS
An alternative method for solving homogenous and non-homogenous linear differential equation systems used in chemical kinetics and pharmacokinetics on the basis of flow graph principles has been proposed.
Classical method of solving these systems with flow graphs involves the employment of Laplace transform before depicting a flow graph and the inverse Laplace transform after using the Mason's rules. A short description of flow graph algebra has been presented. One model very often encountered in pharmacokinetics was solved. Our proposed method is simpler and more direct, eliminating the Laplace transforms. The calculus is made directly on the base of the flow graph representing the image of reaction scheme (pharmacokinetic model).
C-H AGOSTIC INTERACTION IN TUNGSTEN COMPLEXES
The ‘agostic’ interaction between transition metal centres and a C–H bond1remains a topic of enduring interest,
and current research ranges from fundamental studies into the nature of the chemical bond to highly applied work examining the role of agostic bonds in catalysis.
The [W(TpMe2)(CO)2{η2-B(Et)CH2Me}] was studied by X-ray diffraction, Wadepohl et. al.2 observed that in this complex
a β-agostic interaction is present. The same complex was studied using computational techniques. All calculations were carried out with the ONIOM method3,
4 as implemented in the Gaussian98 package. The method applied for the QM region was Becke3LYP. Two minima and a transition state were localised by QM/MM calculations.
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