Wyniki wyszukiwania - BazTech

1

Architektury supramolekularne jako wynik samoorganizacji w kompleksach jonów metali d- i f- elektronowych

Patroniak V.

Wiadomości Chemiczne

|

2010

|

[Z] 64, 3-4

285-318

EN

The use of transition metal complexes of bridging multidentate ligands to construct predictable, self-assembled small inorganic systems and multi-dimensional infinite networks is an area of chemistry which has received ever-increasing attention over the recent years. Self-organization occurs usually from a mixture of components (organic ligands, salt crystals, and sometimes solvent molecules). The products exhibit a notable thermodynamic and kinetic stability and their components should contain all the information necessary for a correct assembly to occur [1–6]. Self-assembly has recently been studied in many types of organic and inorganic systems. This latter approach has proven particularly successful for the generation of a wide spectrum of architectural topologies such as for example, helicates [7–11], rotaxanes [12, 13], clusters [14–16], ladders [17–19], cages [20–22], grids [23–25] and molecular wheels [26–28], etc., based on ligand design and an application of suitable coordination geometries for the assembling system. The structure of supramolecular complexes depends strongly on the ligand substituent, the ligand conformation, the metal ion, the counterion, the solvent, and the reaction conditions [29–37]. Such compounds may exhibit novel physical and chemical properties with a potential use in supramolecular engineering, nanotechnology, biomedical inorganic chemistry, biological catalysis, and in the area of sensors [38–46]. The review has been prepared on the results of my own studies in the field [47–59] and focused on structural diversity and characterization of supramolecular complexes. The architectures of these compounds generated by self-assembly of polypirydyl ligands with d-and f-metal ions are fascinating and attractive because of their unusual properties and prospective implementation in many application [60–74].

2

Spectrophotometric study of interaction between selected bile acids and cyclodextrins

Zarzycki P. K., Baran M. J., Harasimiuk F. B.

Pomiary Automatyka Kontrola

|

2010

|

R. 56, nr 4

355-359

EN

The main goal of present work was to explore the host-guest complex formation between selected bile acids (dehydrocholic, cholic, deoxycholic, taurodeoxycholic, glycodeoxycholic, glycocholic and chenodeoxycholic acid) and cyclodextrins (ß-cyclodextrin and its hydroxypropyl derivative) at sub-ambient and elevated temperature, using as a probe the phenolphthalein-cyclodextrin inclusion complex detected via UV-Vis spectrophotometry. In order to explore the general trends in the complexation ability of the bile acids by macrocycles investigated, the quantitative data set containing ?AU values was analyzed by principal component analysis.

PL

W pracy przedstawiono wyniki badań nad oddziaływaniem wybranych kwasów żółciowych (kwas dehydrocholowy, cholowy, deoksycholowy, taurodeoksycholowy, glikodeoksycholowy, glikocholowy oraz chenodeo-ksycholowy; rys. 1) z substancjami makrocyklicznymi (ß-cyklodekstryna i jej hydroksypropylowa pochodna) w różnych temperaturach (0 oraz 30oC), wykorzystując jako detektor kompleks inkluzyjny makrocykli z fenoloftaleiną (rys. 2 i 3). Z punktu widzenia chemii analitycznej i diagnostyki medycznej kwasy żółciowe są grupą związków trudnych w detekcji i analizie ilościowej. Zastosowanie kompleksów supramolekularnych typu gość-gospodarz, w których skład wchodzi substancja barwna np. fenoloftaleina, umożliwia zastosowanie spektroftometrii do detekcji kwasów żółciowych oraz badań ich oddziaływania ze związkami makrocyklicznymi. Jest to istotne z punktu widzenia zastosowań praktycznych np. analizy kwasów żółciowych w materiałach biologicznych rozdzielanych metodami chromatograficznymi. W prezentowanej pracy dane eksperymentalne (?AU) uzyskane za pomocą spektrofotometrii UV-Vis (rys. 4) były analizowane metodą PCA (Principal Component Analysis; rys. 5). Wyniki analizy wskazują na kluczową rolę temperatury oraz podstawnika przy węglu C12 szkieletu sterydów na siłę oddziaływania badanych kwasów żółciowych z cyklodekstrynami (rys. 6). Zaobserwowano, iż w warunkach mikrochromatografii planarnej jest bardzo trudno rozdzielić parę kwasów chenodeoksycholowy/ deoksycholowy (rys. 7). Uzyskane wyniki wskazują na możliwość poprawy rozdzielania chromatograficznego wybranych par kwasów zółciowych przy zastosowaniu faz ruchomych modyfikowanych cyklodekstrynami (rys. 8).

3

Rezorcarenty i ich pochodne. Część 1. Synteza i struktura

Urbaniak M., Iwanek W.

Wiadomości Chemiczne

|

2004

|

[Z] 58, 3-4

203-243

EN

One of the main goals of supramolecular chemistry is to use bowl-shaped molecules to recognize a substrate on the basis of size, shape, functionality and electrostatic profile. Design and investigation of molecules which are capable to form well defined, functional supramolecular structures has attracted considerable interest during the last three decades. This concept was borrowed from biological systems where the process of molecular recognition is central to the chemistry of life. Among the molecules possessing the suitable shape and properties, there is a class of polycyclic mocromolecules-the resorcarenes. They have the cavities, whose geometries depend on the molecular structure, and the walls of these cavities contain active sites, which serve for the substrate binding. Availability of many active sites makes such a molecule a suitable platform for the synthesis of many new types of resorcarenes. The synthesis of compounds of type l, derived from resorcinol and aldehydes, has already been described very carly but the structures of such a compound were confirmed by Erdtman et. al. in 1968 by crystallographic analysis. The non-planar structure of resorcarenes makes it possible for them to exist in several different conformations. Resorcarenes can be prepared in high yield in a one-step procedure with neither template nor high dilution effects. In most cases, the mineral acids are applied as the catalysts for condensation of polyhydroxyphenols (i.e. pyrogallol or resorcinol) or the derivatives thereof with aldehydes. However, preparations of these macrocycles making use of Lewis acids or bases as catalysts are known also. The effective method of controlling the spatial structure and physico-chemical properties of resorcarenes consists in: modification of the aldehyde type used, introduction of the substituent ortho to the hydroxy groups, and functionalization of the OH groups. The electrophilic substituents such as bromo or diazo group can be readily introduced at the ortho position. However, the most freduently employed electrophilic substitution in resorcarenes in the Mannich reaction. Depending on the type and amounts of the reactants, one can obtain the aminomethyl, oxazine or oxazolidine derivatives. In turn, the hydroxy groups of resorcarenes can be functionalized in several ways, by: 1. Modification of all OH groups, e.g. by formation of the ester, ether, alcohol, silicon, phosphorus and bipyridyl derivatives; 2. Selective modification of OH groups by formation of the acetyl derivatives; 3. Covalent linking of the hydroxy groups of the neighbouring phenyl rings with the bridges containing the appropriate number of atoms. The last of the above approaches leads to the synthesis of cavitands which are in turn employed in the synthesis of the double resorcarenes, named carcerands and carcaplexes. The presented paper is a continuation of work published in Wiadomości Chemiczne in 1997. Now, we present the development of methods for the synthesis of different derivatives of resorcarenes described in literature till now. The second part will concetrate on complexation properties of resorcarenes and the third part on their applications.

4

Kompleksy kratkowe

Patroniak V.

Wiadomości Chemiczne

|

2004

|

[Z] 58, 1-2

59--79

EN

The supramolecular chemistry is one of the most intensely developed fields of contemporary chemistry. Supramolecular chemistry may be defined as "chemistry beyond the molccule", bearing on the organized entities of higher complexity that result from association of two or more chemical species hold together by intermolecular forces [1]. Self-assembly involves the direct and spontaneous formation of a closed superstructure or polymer from a mixture of components (organic ligands, salts crystals, and sometimes molecules of solvents). The product exhibits a notable thermodynamic and kinetic stability and its components should contain all the information necessary for a correct assembly to occur. Self-assembly has recently been achieved in many types of organic and inorganic systems [2-I 1]. The inorganic self-assembly involves spontaneous generation of well-defined metallo-supramolecular architectures from mixtures of organic ligands and metal ions. This latter approach has proven particularly successful for the generation of a wide spectrum of architectural topologies such as for example, inorganic double [12-15], triple [16-20] and quadruple [21] helicates [22-25], rotaxanes [26-29], clusters [30-35], racks [36, 37], ladders [38, 39], cages [40-47], wheels [48, 49], grids [50-90] etc., based on ligand design and the application of suitable coordination geometries for the assembling system. Among them, there is an increasing interest in grid-type complexes, based on ligands containing oligopyridine type of sites and a various d-metal ions. The grids are the thermodynamically most stable motif when metal ions of octahedral coordination geometry are combined with a planar ligand containing tridentate binding sites. Such compounds may exhibit novel physical and chemical properties with interesting and useful potential applications in supramolecular engineering, nanotechnology, biomedical inorganic chemistry, biological catalysis, and in the area of sensors. Transistors incorporating complexes containing cobalt ion bonded to polypyridyl ligands have been reported recently, which is expected to be important in molecular electronics and in the study of the physics of nanoscale systems [91] The structure of grid-type complexes depends strongly on the ligand substituent, the ligand conformation, the metal ion, the counterion, the solvent, and the reaction conditions. The paper has been prepared on the basis of literature in the field and results of my own studies. The main contribution is a deseription of synthesis and characterization of the grid-type complexes, taking into regard their untypical properties and structure.

5

Kwasy żółciowe jako komponenty architektoniczne w chemii supramolekularnej

Łotowski Z.

Wiadomości Chemiczne

|

2003

|

[Z] 57, 11-12

1093--1132

EN

One of the most important fields in modern synthetic chemistry is the preparation of molecules which can recognize and bind others and then catalyze transformations of the bound molecules i.e. „artificial enzymes”, and the construction of systems which can reproduce themselves or otherwise store and process information at the molecular level [5 ? 8]. The above mentioned properties of these novel synthetic structures will result not only from the presence therein of the various required elements, but also from their relative arrangements in space and the three-dimensional shape of the overall assembly. In other words, spatially separated elements combine to achieve an overall effect in these structures. Hence, there will be a requirement for molecules with well-defined geometries in which conformational freedom is kept under close control. This criterion can be met by designs based on rigid frameworks. The steroid nucleus is one of the largest rigid units which is readily available. There are many steroidal compounds which might be chosen as starting materials for more elaborate frameworks. However, bile acids are the most valuable group of these compounds due to their chemically different hydroxyl groups, enantiomeric purity, unique amphiphilicity, availability and low cost. Bile acids are natural polyhydroxylated steroidal acids existing in bile as sodium salts of N-acyl derivatives of glycine and taurine. They are synthesized from cholesterol and can solubilize hydrophobic substances by the formation of micellar aggregates and thus help in the digestion of fat lipids. In this review applications of bile acids as building blocks in the synthesis of macrocyclic and also open-chained supramolecular hosts are presented.

6

Od oddziaływań supramolekularnych do molekularnych

Brandt K., Siwy M., Lach D.

Wiadomości Chemiczne

|

2000

|

[Z] 54, 5-6

389-434

EN

The review is focused on the problems of supramolecular assistance to molecular synthesis which means the employment of supramolecular interactions to control the chemical synthesis, i.e. to guide the regio- and/or stereoselective formation of covalent and/or mechanic bonds. Such an approach results from the tendency to mimic processes occurring in natural biological systems. The special attention is focused on the recent achievements in this field, i.e. on the design of so-called intelligent substrates, which contain in their structure the requisite stereoelectronic information needed to self-assemble spontaneously into a supramolecular intermediate, which converts further into a desired final product after the formation of one or more covalent bonds. Among the unusual structures obtained using this synthetic paradigm, mechanically interlocked molecular compounds, i.e. rotaxanes, catenanes and their supramolecular precursors: psedorotaxanes, are described in more detail, as they display features of bistable chemical switches, and therefore evolve currently a great scientific interest due to their prospective applications in nanotechnologies. Several examples have been given of supramolecular assistance to other complex chemical syntheses, in particular of organic compounds, organo(cyclophosphazenes) and oligonucleotides, enabling to perform them quickly and selectively from polyfunctional reagents, without the necessity to use any protecting groups. It has been emphasized that supramolecular interactions play a special role in guiding so-called self-replication processes of the molecules containing in their structure both reactive groups, able to undergo co-condensation, and complementary to those contained in the substrates supramolecular synthons (motifs), capable to form appropriately oriented ternary complexes with these substrates, in which the functional groups are in favourable position to interact towards the desired product. An influence of spontaneous self-assembly of the substrates, preceding their linking via covalent bond(s), on regio- and stereochemistry of the occurring processes has been discussed, with the special attention being paid to the role of so-called templates (previously named matrices), determining the orientation of the substrates due to the stabilization of particular transition states. Several types of templates have been discussed: complementary hydrogen bonding, metal cations (alkali metal, transition metal), p-donor-p-acceptor interactions and various combinations of the above mentioned; the examples of the respective template-driven syntheses have been quoted. The reactions of functional macrocyclic ligands, assisted by supramolecular interactions with the nucleophilic ion-paired co-reagents, have been only briefly mentioned and limited to the examples of the exchange reactions of benzo-crowns with substituents in aromatic rings, and of chlorocyclophosphazene-crowns.

7

Samoorganizacja w kompleksach metali

Radecka-Paryzek Wanda

Wiadomości Chemiczne

|

1999

|

[Z] 53, 11-12

871-885

EN

Inorganic self-organisation involves the spontaneous generation of well-defined supramolecular architectures from metal ions and organic ligands. The basic concept of supramolecular chemistry is a molecular recognition. When the substrate are metal ions, recognition is expressed in the stability and selectivity of metal ion complexation by organic ligands and depends on the geometry of the ligand and on their binding sites that it contains. The combination of the geometric features of the ligand units and of the coordination geometries of the metal ions provides very efficient tool for the synthesis of novel, intriguing and highly sophisticated species such as catenanes, box structures, double and triple helicates with a variety of interesting properties. The article will focus on the examples of inorganic self-organisation involving the templating as a first step for the assembly of supramolecular structures of high complexity.