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1

Proces samo-dysproporcjowania enancjomerów podczas chromatografii kolumnowej

Wzorek Alicja, Kwiatkowska Magdalena, Urbaniak Mariusz, Gawdzik Barbara

Wiadomości Chemiczne

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2023

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[Z] 77, 5-6

425--448

EN

The review is devoted to self-disproportionation of enantiomers (SDE) phenomenon which has been observed for many different classes of chiral organic compounds. The SDE phenomenon occurs when the fractionation of an enantioenriched sample due the application of a physicochemical process under achiral conditions results in the variation of the proportion of the enantiomers present across the fractions, though the overall composition in terms of the sample ee remains unchanged. The SDE process can be considered in terms of separating the excess enantiomer from the racemate. The basic terminology related to SDE was described. The formation of the SDE under chromatographic conditions is the result of an association process occurring in a solution of a chiral, non-racemic compound. Information on preferred interactions leading to homo-/heterochiral supramolecules can be provided by quantum chemical calculations, NMR spectroscopy and comparison of crystal structures of the racemic and enantiomeric crystals. Several examples of the chromatographic experiments with different classes of compounds were given in two purposes 1) to highlight the possibility of application SDE during column chromatography as the method for enantiopurification of the chiral, non-racemic compounds; 2) to demonstrate that a standard workup (chromatographic purification, evaporation) can alter the stereochemical outcome of asymmetric reactions.

2

Asymetryczne reakcje pericykliczne katalizowane kompleksami magnezu

Czombik Anna

Wiadomości Chemiczne

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2022

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[Z] 76, 9-10

755--788

EN

II Group-metals, like magnesium, are one of the most widespread elements in the environment. The abundance of II-group metals in the Earth’s crust is over 108 times greater than the precious metals. For the industrial applications, the important factors are the low costs of production and higher accessibility of their compounds. This puts the spotlight on alkaline-earth metals competing with transition elements as catalysts in organic synthesis. Features of their derivatives, like mild Lewis acidity and strong Brønsted basicity enabled them to catalyze reactions where Lewis-acidactivation of the substrate is essential. In this review the emphasis was put on magnesium-catalyzed pericyclic reactions, which are recognized as one of the most important methods of new carbon-carbon or carbon-heteroatom bonds formation. Using the catalysts based on II-group metal cations and chiral ligands, a highly stereoselective conversion of achiral substrates into enantioenriched products is possible. The Mg-based catalysts have been used in Diels-Alder, ene and 1,3-dipolar additions. Described synthesis methods were characterized by high efficiency (chemical yields and enantiomeric excesses). Where applicable, the relationships between the structure of catalyst/substrates, conditions and efficiency were discussed. Just now there are a few applications, for example in synthesis of alkaloid (–)-manzacidine or antibiotic of algal origin – (–)-malyngolide.

3

Kompleksy metali dużych makrocykli iminowych i aminowych

Lisowski Jerzy

Wiadomości Chemiczne

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2021

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[Z] 75, 5-6

603--629

EN

Macrocyclic complexes continue to attract considerable attention due to their significance in biological systems, catalysis, medical diagnostics and other fields. While the most intensively studied macrocycles containing donor nitrogen atoms are tetraazamacrocycles such as porphyrins or cyclen derivatives, larger macrocyclic ligands containing up to 18 (or even more) donor atoms are also known. Due to their enlarged size, these macrocycles can bind large metal ions such as lanthanide(III) ions or bind multiple metal ions. In this review a subclass of large macrocycles will be discussed i.e. macrocyclic amines and imines that can be generated in the condensation of diamines with dicarbonyl compounds, in particular with 2,6-diformylpyridine or 2,6-diformylphenols. These macrocycles of various sizes lead to a rich variety of structures of metal complexes, including polynuclear complexes. Moreover, macrocycles derived from enantiopure trans-1,2- diaminocylohexane form chiral metal complexes that exhibit unusual effects such as helicity inversion, enantioselective self-recognition or enantiodiscrimination of organic guest molecules.

4

Chiralne amidki litu : właściwości i wybrane zastosowania syntetyczne

Piwońska Magdalena

Wiadomości Chemiczne

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2021

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[Z] 75, 5-6

771--798

EN

Reactions involving carbonyl groups are one of the most important transformations in organic chemistry. The nucleophilic properties of carbonyl compounds, when they are in the form of enolate ions, offer many possibilities for creating new carbon-carbon bonds in reactions with electrophiles. In the case of cyclic ketones, enolate formation can be stereocontrolled by deprotonation with the use of chiral lithium amides. Stereoselective formation of the chiral lithium enolate determines the stereochemistry of the product of the subsequent reaction with the electrophile. The induction of chirality in the reaction of enolate ions with electrophiles can also be achieved by using metals other than lithium, i.e. magnesium. When other alkali metals are used, an organometallic catalyst containing a chiral ligand must be present in the reaction. The presence of particular structural elements allow distinguishing the chiral lithium amides between eight major classes. Due to the high reactivity of lithium enolates, they are often converted into the silyl enol ether. This is done in two ways: internal quench (in situ reaction with TMSCl) or external quench. Due to aggregation of the chiral lithium amides and, thus, a decrease in asymmetric induction, the addition of LiCl is necessary for reactions run in external quench conditions. Although there are known examples of the use of chiral lithium amides in a catalytic amount in the deprotonation of epoxides, there is only one example of using less than stoichiometric amounts of chiral lithium amides in the deprotonation of ketones. There are many reports in the literature on the use of chiral lithium amides in total syntheses. The chiral lithium amides were used to form chiral enol silyl ether intermediates, e.g. in synthesis of chlortetaine or (+)-ibogamine. They are also used to form chiral lithium enolates which reacts directly with electrophiles, e.g. in synthesis of lasonolide A.

5

Asymetryczna aminokataliza : użyteczne narzędzie w tworzeniu chemicznej różnorodności

Skrzyńska Anna, Przydacz Artur, Dyguda Mateusz, Topolska Aleksandra, Albrecht Łukasz

Wiadomości Chemiczne

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2020

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[Z] 74, 3-4

255--284

EN

Over the last 20 years asymmetric aminocatalysis has emerged as highly useful and reliable method of asymmetric synthesis. It involves the use of primary or secondary amines as catalysts of various stereoselective transformations of carbonyl substrates. Owing to the diverse activation strategies available in asymmetric aminocatalysis, it became a method of choice when the functionalization of prochiral aldehydes and ketones is considered. As a consequence, a direct and straightforward access to various chiral building blocks is possible that is of relevance to modern stereocontrolled organic synthesis. In the manuscript, the development of various aminocatalytic activation concepts is described and recent, selected contributions to this field of chemistry discussed. Main advantages of these strategies are highlighted providing an overview of this fascinating area of research.

6

Influence of chirality on two-dimensional deformations in twisted flexoelectric nematic layers

Buczkowska Mariola

Scientific Bulletin. Physics / Lodz University of Technology

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2019

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Vol. 40

5--12

EN

Two-dimensional deformations induced by electric field in twisted nematic cells filled with liquid crystal possessing flexoelectric properties were simulated numerically. The influence of chiral dopants on the occurrence and structure of the spatially periodic patterns was investigated. It was found that the chirality influences mainly the direction of the periodic patterns whereas the threshold voltage for deformation and the width of the stripes are weakly affected

PL

Dwuwymiarowe deformacje indukowane polem elektrycznym w warstwach ciekłych kryształów nematycznych posiadających właściwości fleksoelektryczne były symulowane numerycznie. Zbadano wpływ chiralnych domieszek na strukturę tych odkształceń i ich rozwój pod wpływem pola elektrycznego. Stwierdzono, że chiralność wpływa głównie na kierunek odkształceń, podczas gdy napięcie progowe na odkształcenie i przestrzenny okres odkształceń słabo zależą od chiralności nematyka. Stwierdzono, że chiralność wpływa głównie na kierunek odkształceń, podczas gdy jej wpływ na napięcie progowe i na przestrzenny okres odkształceń jest nieznaczny.

7

Elastic moduli of carbon nanotubes with new geometry based on FEM

Fereidoon A., Rajabpour M., Hemmatian H.

Journal of Theoretical and Applied Mechanics

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2014

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Vol. 52 nr 1

235--245

EN

In this paper, the elastic moduli of elliptic single walled carbon nanotubes (ESWCNTs) are described. A three-dimensional finite element (FE) model for such carbon nanotubes is proposed. The covalent bonds are simulated by beam elements in the FE model. The elastic moduli of beam elements are ascertained from a linkage between molecular and continuum mechanics. The deformations of the FE model are subsequently used to predict the elastic moduli of ESWCNTs. In order to demonstrate the FE performance, the influence of length, chirality, diameter and cross sectional aspect ratios on the elastic moduli (Young’s modulus and shear modulus) of ESWCNTs is investigated. It is found that the cross sectional aspect ratio of ESWCNTs significantly affects the elastic moduli. With increasing cross sectional aspect ratio, the Young’s modulus and shear modulus decrease. As a result, every change in geometry operates as a defect and decreases the elastic moduli. With increasing the length, Young’s modulus increases and the shear modulus decreases.

8

Synthesis of new chiral inducer and preparation of semi-conducting polymer films showing fingerprint structure

Hayashi H., Kawabata K., Goto H.

International Letters of Chemistry, Physics and Astronomy

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2014

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Vol. 8

6--12

EN

We synthesised a rod like shaped new chiral inducer to construct chiral liquid crystal electrolyte solution. Next, electrochemical polymerisation was carried out in the chiral liquid crystal electrolyte solution. The surface morphology of the polymers were observed with polarising optical microscopy. Synthesis of the new chiral inducer and preparation of semi-conducting thin film in the cholesteric liquid crystal electrolyte solution were performed.

9

Trans-1,2-diaminocykloheksan – niezwykła kariera outsidera

Petryk M., Kwit M.

Wiadomości Chemiczne

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2013

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[Z] 67, 5-6

393--442

EN

An enantiopure trans-1,2-diaminocyclohexane is one of the most widely used chiral diamines in modern organic chemistry. This chiral building block, readily available from waste industrial products, emerges as a major figure in the field of asymmetric synthesis. The unique structural and conformational properties of trans-1,2-diaminocyclohexane make it very useful for the development of new synthetic strategies, taking advantage of its geometrical pre-organization. In this short article, we will highlight the utility of enantiomerically pure trans-1,2-diaminocyclohexane derivatives as broad-range chiral reagents and ligands for catalytic cycles. A brief overview of the aspects of applications in the field of molecular recognition will also be given.

10

Alkaloidy kory chinowej : małe cząsteczki, które wiele mogą

Kacprzak K., Czarnecki P.

Wiadomości Chemiczne

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2013

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[Z] 67, 5-6

443--493

EN

Cinchona alkaloids comprising quinine, quinidine, cinchonidine and cinchonine as the major members constitute a unique class of quinoline alkaloids with tremendous impact on human civilization (Section 1). The odyssey of Cinchona alkaloids began with the discovery of their antimalarial properties followed by antiarrhytmic action of quinidine. Currently medicinal chemistry of Cinchona alkaloids derivatives develops rapidly and many other activities such as cytotoxic, multidrug resistance inhibitory have been demonstrated (Section 5) [5]. Beside medicine Cinchona alkaloids gave also the fundaments of stereochemistry and asymmetric synthesis. An extraordinary catalytic potency of parent and modified Cinchona alkaloids (deserving privileged catalyst classification) include more than 50 types of diverse stereoselective reactions, with few spectacular such as asymmetric dihydroxylation of alkenes or heterogeneous α-ketoesters hydrogenation (Section 3) [3]. Last but not least the portfolio of applications of Cinchona alkaloids includes resolution of racemates by diastereomeric crystallization or by the use of Cinchona- -based chiral stationary phases for ion-exchange enantioselective chromatography and other recognition or sensing systems (Section 4) [166]. Easy transformation of Cinchona alkaloids (for example by click chemistry) into other chiral and modular building blocks together with current pressure on a more intense exploration of sustainable products make cinchona alkaloids of primary importance for modern synthetic, catalytic and medicinal chemistry. The aim of this review which covers over 200 references is to briefly summarize all aspects of Cinchona alkaloid chemistry and biology with the special emphasis on new applications.

11

Wpływ chiralności na aktywność biologiczną cieczy jonowych

Feder-Kubis J.

Przemysł Chemiczny

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2013

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T. 92, nr 9

1598-1601

PL

Przedstawiono syntezę nowych chlorków 1-[(±)-mentoksymetylo]-X-dimetyloamino- pirydyniowych (X=3 lub 4) oraz ich aktywność mikrobiologiczną. Dla otrzymanych racemicznych soli wyznaczono temperatury topnienia, a strukturę soli potwierdzono za pomocą protonowego i węglowego magnetycznego rezonansu jądrowego. Ponadto określono wpływ chiralności cieczy jonowych na ich właściwości przeciwdrobnoustrojowe. Aktywność form optycznie czynnych przewyższa w sile działania nawet stukrotnie aktywność racemicznych odpowiedników.

EN

1-[(±)-Menthoxymethyl]-X-(dimethylamino)pyridinium chlorides (X=3 or 4) were synthetized and studied for microbiol. activity. The resulting salts were analyzed for purity (thin layer chromatog.), content of cationic active substance (titrn.), mp. and chem. structure (NMR). The chirality impact of the ionic liqs. on their antimicrobial activities was obsd. The racemic counterparts were much less effective than the optically active chlorides.

12

Specific mobility of selected phytochemicals in thin-layer chromatographic systems and its possible relevance to pharmacokinetics

Knaś M., Szeremeta D., Polański J., Sajewicz M., Kowalska T.

Acta Chromatographica

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2013

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Vol. 25, no. 4

765--776

EN

In many publications on the thin-layer chromatographic analysis of the medicinal plant extracts, striking skewness of the separated chromatographic bands with many phytochemicals can be seen, although no attention has ever been paid to this odd mass transfer effect. In our earlier studies on the thin-layer chromatographic enantioseparation of certain low molecular weight carboxylic acids, lateral relocation thereof (i.e., the side-wise deviation of their migration route from linearity) was registered. Then we found out that lateral relocation was observed with these analytes only, which structurally resembled molecular rotors. In this study, we investigate the role played by the thin-layer chromatographic stationary phases in lateral relocation of botanically relevant molecular rotors. Thus, three carboxylic acids were selected as the test analytes, all of them resembling molecular rotors and abundantly present in the medicinal plant extracts. We selected two most popular thin-layer chromatographic stationary phases also, i.e., silica gel (characterizing with microcrystalline chirality) and alumina (achiral). Lateral relocation of the test analytes was observed on the silica gel stationary phase only. A conclusion was drawn that the chiral stationary phase makes a complementary contribution to lateral relocation (along with the propeller-like molecular structure of the analytes). In our view, specially devised thin-layer chromatographic systems can prove a convenient nano-platform for future investigation of the drug transport patterns, advantageous in the pharmacokinetic studies.

13

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.

14

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.

15

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.

16

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).

17

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.

18

NMR spectroscopy in studies of new chiral ionic liquids

Feder-Kubis J.

Polimery

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2011

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T. 56, nr 9

676-681

PL

Przedstawione w pracy chiralne ciecze jonowe [CILs, wzory (I)—(IV)] badano by ocenić możliwość ich zastosowania w roli katalizatorów, reagentów oraz rozpuszczalników w syntezie asymetrycznej, jak również w polimeryzacji stereoselektywnej. Omówiono szczegółowo wykorzystanie spektroskopii NMR do badań nowych CILs. Analizując widma NMR czwartorzędowych soli amoniowych z podstawnikiem (1R,2S,5R)-(–)-mentoksymetylowym zwrócono uwagę na charakterystyczne dwa dublety pochodzące od diasteretopowych protonów grupy metylenowej (układ spinowy AB) znajdującej się między czwartorzędowym atomem azotu i tlenem (rys. 1). W celu precyzyjnego określenia położenia każdego protonu i węgla części mentolowej oraz szczegółowego przypisania rodzaju sygnałów wykonano i omówiono widma dwuwymiarowe 2D NMR (rys. 2). Analiza widm 1H NMR i 13C NMR badanych CILs wykazała przesunięcia sygnałów chemicznych, w stosunku do położenia analogicznych sygnałów grup atomów wodoru (widma 1H NMR) oraz grup atomów węgla (widma 13C NMR) w chlorkach. Uszeregowano zarówno aniony, jak i syntezowane związki (w zależności od rodzaju aminy będącej częścią strukturalną czwartorzędowej soli amoniowej), pod względem zdolności ekranujących.

EN

Chiral ionic liquids (CILs) were discussed as new potential media for enantioselective organic synthesis, including enantioselective polymer synthesis. NMR spectra of new CILs, whose structures are shown in formulas (I)—(IV), were investigated in detail. In the case of 1H NMR analysis of those compounds two characteristic doublets were observed — diasterotopic protons (AB spin system). In order to precisely determine the spectral position of each proton and carbon, but also to attribute in a detailed way the type of their signals, two-dimensional spectra were obtained. Additionally, 1H NMR and 13C NMR spectra indicated notable differences in the chemical shifts depending on the anion used. Comparing the differences between values of the chemical shifts, the anions, but also the quaternary ammonium salts, depending on the amine used, were ordered according to their increasing shielding capacities.

19

Circular dichroism and electroluminescence of poly(diacetylene) film with chirality

Kohn H., Fukada M., Ohshima Y., Manaka T., Iwamoto M.

Materials Science Poland

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2009

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Vol. 27, No. 3

727--734

EN

By applying only circularly polarized light (CPL) irradiation to evaporated achiral diacetylene (DA) monomer film during its photopolymerization process, we prepared poly(diacetylene) (PDA) films that show circular dichroism (CD). The left- or right-handed chirality was induced in the polymerized PDA films by the left- and right-CPL irradiation. We studied physical properties of the prepared PDA films, including their electrical and optical properties. The induced chirality in PDA films was not destroyed after annealing at 353 K for 10 min, whilst their blue-phase was changed into a red one. The intensity of the CD signal was dependent on the substrate temperature employed for the monomer deposition. Electroluminescence was found to be enhanced with the polymerized PDA films installed as an active layer of organic field-effect transistors.

20

Chemia i technologia chiralna w środkach ochrony roślin

Połeć I., Komorowska-Kulik J., Legocki J.

Przemysł Chemiczny

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2007

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T. 86, nr 6

530-533