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Structural and spectroscopic studies on the formation of lipoplexes between DNA and cationic gemini surfactants

Andrzejewska W., Pietralik Z., Taube M., Skrzypczak A., Kozak M.

Polimery

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2014

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T. 59, nr 7-8

569--574

EN

The process of complex formation between cationic gemini surfactants, 3,3'-[a,w-(dioxaalkane)]bis(1-dodecylimidazolium) dichloride, with deoxyribonucleic acid (DNA) was studied. The study was performed for ten surfactants having spacer groups of different lengths used in 6 concentrations (5 mM, 2 mM, 1 mM, 0.5 mM, 0.2 mM, 0.1 mM) and a 6.5 µM DNA solution. The complex formation was verified by circular dichroism spectroscopy and gel electrophoresis. The complexes were found to be stable and the process of complex formation was reproducible, efficient and immediate.

PL

Zbadano proces kompleksowania kationowych surfaktantów typu gemini — dichlorków 3,3'-[a,w-(dioxaalkane)]bis(1-dodecyloimidazoliowych) z kwasem deoksyrybonukleinowym (DNA). Wykorzystano dziesięć surfaktantów różniących się długością grupy łącznikowej, w postaci roztworów o 6 różnych stężeniach (5 mM, 2 mM, 1 mM, 0,5 mM, 0,2 mM, 0,1 mM), oraz 6,5 µM roztwór DNA. Za pomocą spektroskopii dichroizmu kołowego oraz elektroforezy żelowej wykazano, iż zachodzi proces kompleksowania tych cząsteczek. Stwierdzono, że otrzymane kompleksy są stabilne a proces ich powstawania — natychmiastowy, wydajny i powtarzalny.

2

Ultrafast all-optical switch in Bragg-spaced quantum well contained uniform quantum dots

Yu C, Wang T

Optica Applicata

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2012

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Vol. 42, nr 4

821--828

EN

All-optical switching in Bragg-spaced quantum well contained uniform quantum dots (QDs) is investigated in theory. With our design, it is nonresonant excitation for pumping a few meV below the photonic band-gap. The active photonic band-gap structure is shifted by the optical Stark effect, and the circular dichroism and birefringence are induced by the circular polarized pump light. Thus, the optical switching can be realized based on the ultrafast nonlinear effect. The switch, with great advantages of lower requirement of pump light intensity and high contrast ratio, is a promising candidate for the ultrafast all-optical switching devices in future.

3

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.

4

Tartaronitriles – the Derivatives of Tartaric Acid with a Bent Conformation

Gawroński J., Gawrońska K., Waścinska N., Plutecka A., Rychlewska U.

Polish Journal of Chemistry

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2007

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Vol. 81, nr 11

1917-1925

EN

Conformational preferences of dinitrile derivatives of (R,R)-tartaric acid were studied by means of NMR, CD and X-ray diffraction techniques. Where as other derivatives of (R,R)-tartaric acid exist predom i nantly in an extended (T) or bent (G–) conformation, (R,R)-tartarodinitriles show pronounced tendency to ward bent G+ conformation. This is rationalized by the presence of the “gauche effect” in volving maximum number of stabilizing in teractions between the polar groups within the tartarodinitrile molecule.

5

Dimolybdenum Method for Determination of the Absolute Configuration of vic-Diols - Foundations and Developments

Górecki M., Kamińska A., Ruśkowska P., Suszczyńska A., Frelek J.

Polish Journal of Chemistry

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2006

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Vol. 80, nr 4

523-534

EN

A straightforward and versatile method for the determination of the absolute configuration of vic-diols is presented. The proposed method involves the in situ formation of chiral complexes of optically active vic-diols with the achiral dimolybdenum tetraacetate [Mo2(OAc)4] acting as an auxiliary chromophore. The resulting CD spectra are suitable for the assignment of absolute configuration, since the observed sign of Cotton effects arising within the d-d absorption bands of the metal cluster depends solely upon the chirality of the 1,2-diol ligands.An empirically based rule correlating a positive/negative helicity expressed by the O-C-C-O torsional angle with the sign of Cotton effects occurring in the 400-280 nm spectral range has been presented. The applicability of the rule is extended to sterically hindered sec/tert vic-diols.

6

Chrality Probing of Chlorotetrabutyratodiruthenium (II,III) Complexes with vic-amino Alcohols by Circular Dichroism Spectroscopy

Frelek J., Kamińska A., Pakulski Z., Szmigielski R., Priebe W.

Polish Journal of Chemistry

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2005

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Vol. 79 / nr 2

387-399

EN

The circular dichroism (CD) spectra of a variety of vic-amino alcohols in the presence of chlorotetrabutyratodiruthenium(II,III) as an auxiliary chromophore were measured in acetonitrile and chloroform. The method was tested in several model compounds containing acyclic and cyclic amino alcohols, and among them biologically important adrenergic drugs and amino sugars. The study demonstrated that the sign of the Cotton effects obtained is determined by the preferred helicity of the O-C-C-N unit in the chiral complex formed in situ. On this basis, a rule was formulated that correlates a positive (negative) sign of the O-C-C-N torsional angle with a positive (negative) Cotton effect arising around 350 nm and/or with negative (positive) signs of CD spectra bands occurring around 300 and 400 nm.

7

Chiroptical Properties of the Guanidine Chromophore

Siemion I., Ślepokura K., Gawłowska M., Biernat M.

Polish Journal of Chemistry

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2005

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Vol. 79 / nr 2

401-412

EN

The CD spectra of 15 alfa-guanidino-acids, derived from 15 proteinaceous amino acids were measured and analysed. Using L-amidino-proline, L-amidino-prolinol, and L-amidino- 4-hydroxyproline as standards the sector rule for prediction of the sign of the Cotton effect at 190-195 nm, attributed to the guanidine chromophore, was constructed. X-ray analysis of crystal structures of L-amidino-4-hydroxyproline and L-amidinomethionine was also performed.

8

Transient Permeability Induced by Cationic Derivatives of Amphotericin B in Lipid Membranes

Kasumov K., Bolard J.

Polish Journal of Chemistry

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2004

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Vol. 78 / nr 8

1057-1065

EN

Individual ionic channels were shown to be formed through brain phospholipid membranes containing cholesterol, by two-sided addition of cationic derivatives of amphotericin B. At concentrations between 10-8 and 10-7 M, the resulting conductance appeared to be transient. Equilibrium between different antibiotic assemblies inside the membrane was demonstrated by the kinetics of conductance decrease following washing out the antibiotic. To explain the transient characteristics of the induced conductance, it is proposed that the antibiotic, present in solution under self-associated form, binds the membrane and forms pores, then dissociates in the bilayer in a non active monomeric form. This observation may be of importance to explain the delivery of oligonucleotides into mammalian cells, by cationic derivatives of amphotericin B.

9

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 .

10

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.

11

Further Investigations on the Optical Activity of Aromatic Residues in Cyclolinopeptide A Analogues

Siemion I., Cebrat M., Lisowski M.

Polish Journal of Chemistry

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2000

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Vol. 74, nr 7

955-964

EN

CD spectra of a series in methanol solution were analyzed. It was conformed that the aromatic residue in position 9 contribues to a low extent only to the optical activity of the peptide. However, this phenomenon is not a result of the "edge-to-face" interaction of aromatic side chains but rather of the conformation of the aromatic side chain in position 9.

12

Helical Twisting Power and Circular Dichroism as Chirality Observations : development of a sector rule for the intermolecular chirality transfer in a liquid crystal phase

Kubal H., Turk O.

Polish Journal of Chemistry

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1999

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vol. 73 nr 1

209-228

EN

Any chirality measurements, e.g. circular dichroism (CD) or helical twisting power (UTP), should offer a possibility to develop a method for the determination of the absolute configuration. Measurements of CD and optical rotary dispersion (ORD) have been used as standard methods for decades. Since the HTP is very sensitive to variations in the molecular structure, the question of the conditions under which determination of HTP can also be used as a method for the determination of the absolute configuration has been analyzed. It has been found, that a sector rule can be developed for a specific class of compounds. A quadrant or octant rule can be applied successfully for mono- and bis-aminoanthraquinones, as has been shown by a correlation of HTP with the CD of the long-vawelenght charge transfer band. However, a rule of this type breaks down for compounds with low HTP and CD values.

13

Assignment of the absolute configuration of hydroxy and amino carboxylic acids by circular dichroism of their transition metal complexes

Frelek J.

Polish Journal of Chemistry

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1999

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vol. 73 nr 1

229-239

EN

Optically active carboxylic acids can act as uni- or bidentante ligands in complexes of general formula [M2(O2CR)4] +k X-k (M = Mo, Rh or Ru). An in situ exchange of ligand(s) gives rise to several Cotton effects in the spectral range from 800 to 200 nm. In the case of molybdenum complexes with optically active hydroxy and amino acids a hexadecant rule is valid for the two Cotton effects between 400 and 300 nm. For rhodium and ruthenium complexes it was found that the sign of Cotton effects at around 600 nm can be correlated with the structure of investigated acids.