In the last decade molecular imprinted polymers (MIP) have gained great interest in the area of selective recognition various type substances. Scientific work in this field is carried out very intensively - the methods of synthesis are modified and improved, new types of hydride materials are created, as well as new reagents for synthesis. In this case, cyclodextrins (CD) and their analogues show good molecular recognition ability for its unique physical and chemical properties and suitable cavity structure. As a result, these supramolecular ligands can perform various functions in the MIP technology, and the resulting polymeric materials are characterized by high selectivity and binding specificity (recognition) of analytes structurally matched to the MIP cavity. Of particular importance is the fact that cyclodextrins enable the imprinting not only of low-molecular-weight biologically active compounds, but also of high-molecular molecules (proteins, peptides). The numerous hydroxyl groups available in cyclodextrins are active sites that can form different types of linkages. They can be cross-linked with one another, or they can be derivatized to produce monomers that can form linear or branched networks. This article provides a detailed review of MIPs based on CD and their application in the field of separation science and analytical chemistry in recent years. The discussion is grouped according to the different role of CD in MIPs, that is, functional monomer, carrier modifier, etc.
In pursuit for new chromoionophores, it is important to know their functioning, which depends primarily on theirstructure. The structures of chromoionophores were discussed, highlighting the elements that have a significant impact on their operation, i.e. the binding and visualization of metal ion binding. Chromoionophores are composed of a binding and signaling group. Valinomycin, salinomycin and synthetic crown ethers are presented as ionophores. Using the anthraquinone as an example, the function of the chromophore system was defined and discussed. It has been shown that an element connecting the main components of the chromoionophore may also play an important role. The action of chromoionophores is directly related to their acid-base properties, which can influence both ion binding and the visualization of interactions. The examples of aminoanthraquinone derivatives show the influence of the number of groups, position in the anthraquinone ring and the order of amino groups on the basicity of chromoionophores.
Synthesis and isolation of enantiopure compounds remains an important challenge in medicinal, pharmaceutical, alimentary as well as material chemistry. Amongst many methods leading to enantiopure compounds, formation and fractional crystallization of diastereomeric salts of an enantiopure resolving agent is the most popular one. Since its discovery many years went by, and yet it has been performed by the trial and error method. Selection of the suitable resolving agent is crucial for racemic resolution efficiency. Hence, this review is concerned with common features of crystal structures of salts, in which resolving agents, frequently used for separation of racemic acids, are involved. Among them, there are crystal structures of salts of primary, secondary and tertiary chiral amines (1-arylethylamines, ephedrine, pseudoephedrine, deoxyephedrine, chinine, chinidine, cinchonine, cinchonidine, strychnine and brucine). In most of them, cations and anions are involved in characteristic systems of hydrogen bonds leading to formation of cationic-anionic self-assemblies. In this respect, brucine and strychnine appear as unique, because presence of anions usually does not affect formation of common cationic self-assemblies stabilized by weak hydrophobic interactions. Comparison of the common structural motifs indicates different factors being crucial in molecular recognition and in diastereomeric diversification. Formation of common hydrogen bonded cationic-anionic self-assemblies plays a dominant role in molecular recognition of a given acid by most of the studied amines. In turn, formation of common cationic self-assemblies stabilized by hydrophobic interaction plays a crucial role in molecular recognition of a given acid by brucine or strychnine. Diastereomeric diversification can be realized in various ways. In extreme cases, when molecular recognition in crystals of particular diastereomeric salts is similar, diastereomeric diversification is governed by different factors, depending on factors governing molecular recognition. Hydrophobic interactions play an important role in diastereomeric diversification when molecular recognition is governed by hydrogen bonds. In turn, when molecular recognition is governed by hydrophobic interactions, different hydrogen bond systems in crystals of particular salts are responsible for their diastereomeric deversification.
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.
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A critical assessment of the suitability of molecularly imprinted polymers (MIP) for HPLC and binding assays is presented. The goal of this paper is to draw attention to a few simple facts about MIPs which arc relevant for an analytical chemist but which have apparently not yet been collected in such concise form.
PL
Przedstawiono krytycznąocenę przydatności polimerów molekularnego rozpoznania (MIP) w wysokosprawnej chromatografii cieczowej i oznaczaniu wiązania analitu. Celem pracy jest zwrócenie uwagi na szereg prostych faktów, istotnych dla chemika analityka, które dotychczas nie były prezentowane w takiej zwartej postaci.
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