Wyniki wyszukiwania - BazTech

1

Izomery a zapach czyli nos jako stereochemik

Wińska K., Potaniec B., Mączka W., Grabarczyk M., Anioł M., Wawrzeńczyk Cz.

Chemik

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2014

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Vol. 68, nr 2

83--90

PL

Nasz zmysł powonienia jest w stanie rozpoznać wiele zapachów, które pozornie są bardzo do siebie podobne. Dzięki temu, że receptory węchowe są w pewien sposób selektywne możliwe jest ozróżnienie zapachów zarówno enancjomerycznych par lotnych substancji jak i innych stereoizomerów. W niniejszej pracy przedstawione zostały różnice i podobieństwa właściwości pachowych izomerów przestrzennych. Przedstawione związki charakteryzują się odmiennym zapachem oraz intensywnością ale są również takie, gdzie zmiana dotyczy tylko jednej z tych cech.

EN

Our sense of smell is able to recognize a variety of scents, which apparently are very similar. Thus olfactory receptors that are in some way it is possible to distinguish selective enantiomeric pairs fragrances and other volatile substances stereoisomers. This paper presents the differences and similarities odor characteristics of spatial isomers. The compounds are characterized by a different odor and intensity but also those where the change affects only one feature.

2

Wyznaczanie liczby izomerów: od Cayleya do nanorurek

Dobrowolski J.Cz.

Wiadomości Chemiczne

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2006

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[Z] 60, 3-4

171-190

EN

Chemical graph theory is a dynamically developing area of mathematical chemistry which is taught at Chemistry Departments of Polish Universities only seldomly. Especially, molecular graph enumeration, which is one of the oldest branch of chemical graph theory, begun by English mathematician Arthur Cayley's work On the Mathematical Theory ofisomers published in 1874, will always support and stimulate progress of chemistry. In this review, the most important theorem for graph enumeration, known as Pólya Hauptsatz, proven in 1930s by Hungarian and American mathematician George Pólya (1887-1985), is only illustrated. The review remainds early Henze i Blair results of alkanes enumerations as well as quite modern Robinson, Harary, and Balaban enumeration of chiral alkanes. Selected results found for benzenoid hydrocarbons are presented and through the famous Euler polyhedron rule a connection with enumeration of fullerenes and nanotubes is shown.

3

The existence of two isomeric forms of monofluorinated hydrogen sulfide: a new theoretical rationale for experimentally observed infrared spectrum

Babinec P., Leszczyński J.

Polish Journal of Chemistry

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1998

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Vol. 72, nr 7S

1630-1634

EN

In order to explain the discrepancies between the matrix isolated IR spectra of the products of the H2S + F2 reaction and recent computational studies of this system, we have analyzed the potential energy surface of monofluorinated hydrogen sulfide using high level post-Hartree-Fock methods. The molecular geometric and harmonic vibrational frequencies were calculated at the DFT, MP2, and CCSD levels conjunction with the 6-311++G(d,p) basis set. Besides the already proposed HSF isomer which corresponds to the global energetic minimum, a local minimum corresponding to the HFS isomer as well as a transition state structure between these minima have been also characterized. The calculated vibrational frequencies fit well with the experimental IR spectra and also complement previous ab initio calculations on the HSF isomer.

4

Carbyne trefoil knots - are they stable enough to exist?

Dobrowolski J.Cz., Mazurek A.P.

Polish Journal of Chemistry

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1998

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Vol. 72, nr 7S

1593-1603

EN

The structure and stability of non-linear carbon clusters of carbyne type was estimated based on ab initio quantum mechanical calculations. Both the cyclic (cacarbynes) and knotted (knocarbynes) trefoil structure of closed polycarbon chains, containing up to 84 carbon atoms, were considered. Comparison of the calculated spectral properties (IR, (13)C NMR) with those of C60 fullerene provide the basis for experimental identification of Cn cyclic and knotted structures as may have implication for interstellar dust spectroscopy.