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1

Optimization of measurement conditions of Kerr constant in optically active liquids on the example of castor oil

Nowakowski K., Perek A., Izdebski M., Ledzion R., Górski P.

Scientific Bulletin. Physics / Lodz University of Technology

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2014

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Vol. 35

51--64

EN

The results of measurements of Kerr constant in castor oil, obtained by dynamic-polarimetric method are presented. Variable optical path length and four measurement setup configurations were used. They differed by the orientation of polarizer and of quarterwave plate and therefore they were non-equivalent when other, unwanted effects occurred. It was shown that the Kerr constant measurement performed with use of only one system configuration and one length of optical path may be strongly affected by other effects, however taking the arithmetic mean of two results obtained from appropriate system configurations significantly reduces this error. Theoretical dependences were fitted to the experimental results, which allowed for approximation of other constants, like dichroism, linear birefringence and optical activity induced by external electric field (electrogyration).

PL

Przedstawiono wyniki pomiarów stałej Kerra w oleju rycynowym metodą polaryzacyjno-optyczną dla różnych długości drogi światła w próbce przy czterech konfiguracjach pomiarowych, nierównoważnych pod względem wpływu innych niepożądanych efektów, które różnią się orientacjami polaryzatora i płytki ćwierćfalowej. Pokazano, że pomiar stałej Kerra przeprowadzony dla tylko jednej konfiguracji pomiarowej przy jednej długości drogi światła w próbce może być obciążony znacznym wkładem kilku innych niepożądanych efektów, jednakże obliczenie średniej arytmetycznej z pomiarów w dwóch odpowiednio dobranych konfiguracjach pomiarowych pozwala na znaczne zredukowanie błędów pomiarowych. Do wyników doświadczalnych dopasowano zależności teoretyczne, co oprócz pomiaru stałej Kerra pozwoliło także na zgrubne oszacowanie innych wielkości takich jak dichroizm, liniowa dwójłomność i aktywność optyczna indukowana polem elektrycznym (elektrożyracja).

2

Analysis of measurement of quadratic electro-optic effect in castor oil

Izdebski M., Ledzion R., Kucharczyk W.

Scientific Bulletin. Physics / Lodz University of Technology

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2013

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Vol. 34

5--17

EN

This works presents an extended theoretical analysis of the response of experimental setup to an applied electric field during measurements of electro-optic coefficients in optically active liquids using an optical polarimetric technique. The analysis includes liquids belonging to ∞ ∞, ∞ 2 and ∞ Curie symmetry groups and the following phenomena were taken into account: natural optical activity, natural linear birefringence, dichroism, and the effects induced by an applied electric field – linear and quadratic electro-optic effects and linear and quadratic electrogyration. The presented example concerns numerical error analysis for measurement of the quadratic electro-optic effect in castor oil, which exhibits the symmetry ∞ 2 between a pair of plane-parallel electrodes.

PL

Przedstawiono rozszerzoną teoretyczną analizę odpowiedzi układu pomiarowego na przyłożone pole elektryczne podczas pomiarów współczynników efektu elektrooptycznego w cieczy aktywnej optycznie metodą polaryzacyjno-optyczną. Analiza obejmuje ciecze o symetriach wewnętrznych opisanych grupami Curie ∞ ∞, ∞ 2 oraz ∞ i uwzględnia następujące zjawiska: naturalna aktywność optyczna, naturalna dwójłomność liniowa, dichroizm oraz efekty indukowane przez przyłożone pole elektryczne – liniowy i kwadratowy efekt elektrooptyczny oraz liniowa i kwadratowa elektrożyracja. Przedstawiony przykład dotyczy numerycznej analizy błędu pomiaru kwadratowego efektu elektrooptycznego w oleju rycynowym, który wykazuje symetrię ∞ 2 po umieszczeniu go pomiędzy płasko-równoległymi elektrodami.

3

Hiperwalentne związki siarki, selenu i telluru. Część 4. Selenurany i tellurany

Zając A.

Wiadomości Chemiczne

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2012

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[Z] 66, 11-12

1119-1144

EN

In this part selenuranes (10-Se-4 and 10-Se-5) and perselenuranes 12-Se-6 as well as telluranes 10-Te-4 and pertelluranes 12-Te-6 will be presented. The main goal is to describe recent reports on the synthesis, chemical, physical, spectral and conformational behavior, stereochemistry, stability and biological activity of these compounds. Their occurrence as reaction intermediates will also be shown.

4

Hiperwalentne związki siarki , selenu i telluru. Część 3. Sulfuran Martina , sulfurany 10-S-5 i 12-S-6

Zając A.

Wiadomości Chemiczne

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2012

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[Z] 66, 9-10

893-907

EN

In this part of the review one of the most famous 10-S-4 sulfurane called Martin sulfurane together with sulfuranes 10-S-5 and persulfuranes 12-S-6 will be presented. Martin sulfurane has been well known for a relatively long time but it is still useful in organic synthesis as a dehydrating, coupling and oxidizing agent. Its use in selected substitution reactions will be also described. Next, synthesis and selected properties of sulfuranes 10-S-5, mainly sulfurane oxides, and persulfuranes 12-S-6, will be shown. Besides synthetic methods, the review is focused on the investigations of the stability and isomerization of these types of compounds, which is particularly interesting for persulfuranes, because of the presence of three 3c-4e bonds.

5

Hiperwalentne związki siarki, selenu i telluru. Część 2. Sulfurany 10-S-3 i 10-S-4

Zając A.

Wiadomości Chemiczne

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2012

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[Z] 66, 7-8

593-622

EN

The compounds presented herein are sulfuranes 10-S-3 and 10-S-4 containing hypervalent sulfur atom. They have been known for a relatively long time. Nevertheless, they, and especially 10-S-4 species, are still of great interest due to their unique properties. The review presents recent approaches to the synthesis of these compounds, their selected structural, physical, chemical, stereochemical and electronic properties and their use as reagents and catalysts in several reaction types. The presence of structures of these types as intermediates, which explains selected reaction mechanisms, will also be shown.

6

Hiperwalentne związki siarki, selenu i telluru. Część 1. Charakterystyka ogólna

Zając A.

Wiadomości Chemiczne

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2012

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[Z] 66, 5-6

529-541

EN

The goal of this four-part review is a presentation of the results of recent studies on the properties and chemistry of hypervalent sulfur, selenium and tellurium compounds. The term “hypervalency” has been known since 1969 when Musher used it to describe molecules bearing heteroatoms which formally did not fulfill the octet rule. This violation was explained by the postulate concerning the existence of a 3-center 4-electron bond between a hypervalent heteroatom and two axial electronegative ligands. The bond is the a combination of two ligand orbitals and a pz orbital of a central heteroatom which results in the formation of three molecular orbitals. The distances between the central atom and these two ligands are longer than the length of the typical sp2 bonds, such as equatorial ones. Moreover, the effective electron density is shifted from the central atom towards the axial ligands what results in the fulfillment of the octet rule of this atom. The geometry of this system is trigonal bipyramid (Fig. 2), except from compounds having three 3-center 4-electron (3c-4e) bonds which have tetragonal bipyramid geometry (Fig. 3). The term “geometry” includes positions of ligands and lone electron pairs. The stability of hypervalent compounds is affected by a few factors: electronegativity of ligands, formation of five-membered cyclic structures involving the central atom and the number of electron shells of the central atom. Martin proposed three-symbol notation N-X-L for these structures, which was further modified (Tab. 1). Hypervalent compounds can isomerize according to various mechanisms: Berry pseudorotation (Scheme 1), turnstile rotation (Scheme 2), cuneal inversion (Scheme 3), lever mechanism (Scheme 4), or Bailar twist (Scheme 5). Furthermore, hypervalent structures of 10-X-4 and 10-X-5 type with trigonal bipyramid geometry, C1 or C2 symmetry and at least three different ligands can exist as optically active species (Tab. 2, Fig. 5–7, Scheme 6), especially the "spiro" ones, which are resistant to isomerization. In 1977 Martin and Balthazor proposed extended Cahn-Ingold-Prelog convention for description of the absolute configuration of chiral hypervalent compounds (Fig. 5).

7

What is the symmetry of castor oil between metal electrodes?

Izdebski M., Ledzion R., Górski P.

Scientific Bulletin. Physics / Lodz University of Technology

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2012

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Vol. 33

39-53

EN

Presented experimental data show that castor oil between metal flat electrodes can not be satisfactorily described as an isotropic liquid of ∞ ∞ symmetry, even in the absence of an electric field between the electrodes. Correct description of optical properties requires the assumption of 2 ∞ symmetry and consideration of circular birefringence, linear birefringence and dichroism occurring at the same time. Disappearance of linear birefringence and dichroism in castor oil has been observed several days after filling cuvette witch metal electrodes, which suggests the usefulness of such measurements to study the aging processes. The results presented are also important for correct interpretation of future measurements of electro-optic and electrogyration effects in liquids.

PL

Przedstawiono wyniki pomiarów wskazujące, że olej rycynowy umieszczony pomiędzy metalowymi płaskimi elektrodami nie może być zadowalająco opisany jako ciecz izotropowa o symetrii ∞ ∞ nawet przy braku pola elektrycznego pomiędzy elektrodami. Poprawny opis właściwości optycznych wymaga założenia symetrii 2 ∞ oraz uwzględnienia jednocześnie dwójłomności kołowej, dwójłomności liniowej i dichroizmu. Zaobserwowano zanikanie dwójłomności liniowej i dichroizmu w oleju rycynowym po kilkunastu dniach od napełnienia kuwety z metalowymi elektrodami, co wskazuje na przydatność pomiarów tych wielkości do badań procesów starzenia. Przedstawione rezultaty mają także znaczenie dla poprawnej interpretacji przyszłych pomiarów efektów elektro-optycznych i elektrożyracji w cieczach.

8

Eksperymentalne i teoretyczne oznaczanie konfiguracji absolutnej związków chiralnych metodami chiralooptycznymi

Kwit M.

Wiadomości Chemiczne

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2011

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[Z] 65, 1-2

33-58

EN

Chirality is of paramount importance in chemistry and life sciences. Electronic circular dichroism (ECD) as well as optical rotation (OR) are fundamental properties of chiral molecules. These chiroptical properties provide rich information about conformation and configuration of the molecules. Although empirical correlations between chiroptical phenomena, mostly ECD, and molecular stereochemistry have existed for some time, the development of new accurate theoretical methods opened new opportunities for correlation of chiroptical properties with structure. Computational chemistry has made an amazing progress during the past two decades, moving this highly specialized discipline into the mainstream, and making a renaissance in chiroptical methods. This short review is meant as an introduction to the modern approach to optical activity of chiral molecules. Some illustrative applications will put the emphasis on practical applications of the theoretical/experimental analysis of complex molecules including highly flexible bistramide C and noncovalently bonded donor-acceptor dyad. The importance of the solvent effect is briefly discussed and a typical methodology is described and its strengths and weak points are commented.

9

Szkło nieliniowe dla fotoniki. Cz. 1, Nieliniowość elektryczna szkła

Romaniuk R.

Elektronika : konstrukcje, technologie, zastosowania

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2008

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Vol. 49, nr 2

63-68

PL

Szkła, obok półprzewodników i metali, są podstawowym materiałem do budowy elementów w optoelektronice i mikroelektronice. Praktyczna wiedza o szkłach rozszerza się wraz z rozwojem ich zastosowań w telekomunikacji i budowie mikrosystemów. Wiele elementów funkcjonalnych fotoniki budowanych jest ze szkieł nieliniowych. Optyczne zjawiska nieliniowe indukowane w szkle pozwalają na budowę nowych mikroelementów fotonicznych zastępujących złożone rozwiązania klasycznej optyki objętościowej. W artykule, który jest pierwszą częścią cyklu prac o szkłach nieliniowych, dokonano definicji szkła nieliniowego przez porównanie ze szkłem liniowym. Określono obszary nieliniowości szkieł, bazując na wzajemnym oddziaływaniu ośrodka, fali optycznej i innych pól fizycznych. Zebrano tutaj te nieliniowe cechy elektryczne szkieł, które decydują o ich nieliniowych właściwościach optycznych.

EN

Glasses, together with semiconductors and metals, are fundamental materials for building of components for optoelectronics and micro-electronics. Practical knowledge about glasses extends considerably with strong development of their applications in telecommunications and the construction of microsystems. Many functional components of the photonics is manufactured of nonlinear glasses. Nonlinear optical phenomena induced in glasses allow for building of new microcom-ponents, replacing complex solutions of classical volume optics. The paper, which is the first part of a cycle on nonlinear glasses, defines the nonlinear glass by its comparison with a linear one. The areas of glass nonlinearities were defined basing on mutual interaction of medium, optical wave and interacting external physical fields. There were gathered these nonlinear electrical properties of glasses which decide of their nonlinear optical properties.

10

Dichroizm kołowy kwasów nukleinowych. Cz.2. Polimery

Boczkowska M.

Wiadomości Chemiczne

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2002

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[Z] 56, 3-4

203-221

EN

The review presents the theoretical basis for interpretations of CD spectra of polynucleotides. A simplified version of quantum theory of circular dichroism of a polynucleotide by Tinoco and Johnson is presented in details. It is generally assumed that the optical activity of these polymers is dominated by interactions between dipoles of in-plane transitions occuring at neighbouring bases. The interaction of dipoles coming from different bases strictly depends on geometrical arrangement of bases within the helix. As a result information about geometry of the helix can be inferred from the CD spectra. The circular dichroism caused by the disturbance of the electronic system of a base by the presence of a sugar ring is usually omitted in calculations. Such a theoretical approach allows to understand differences between CD spectra of random DNA and RNA. The distance of a base pair from helix axis appeared to be the main factor responsible for these differences]. The approach fails in a case of polymers of non-random sequences, for example containing a repetitive motif of two bases. It is exemplified for the d(CG)n oligomers forming left-handed double helix called Z-DNA, where none of the theoretical calculations is able to predict the inversion of a CD spectrum characteristic for the Z form .

11

Dichroizm kołowy kwasow nukleinowych. Cz.1. Monomery

Boczkowska Małgorzata

Wiadomości Chemiczne

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2002

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[Z] 56, 1-2

39--56

EN

The review presents the theoretical basis for the origin of optical activity of nucleic acids. The optical properties of nucleic bases are discussed in terms of theoretical calculations by Hug and Tinoco. Although nucleic bases are themselves optically inactive, the in-plane (pŽp*) as well as out-of-plane (nŽp*) transition dipoles induced in their rings are responsible for optical activity of nucleosides, nucleotides and polynucleotides. In a case of nucleosides and nucleotides, which are called "monomers", the optical activity originates from the disturbance of the electronic system of a base caused by the presence of a sugar ring. The main factor influencing the character of CD spectra is the torsion angle about the glycosyl bond. The experimental spectra of monomers are dominated by in-plane transitions. In a case of cytidine and guanosine (Rys. 3) the lowering of pH reveals the presence of the out-of-plane transition.