Organic molecular entities

Organic Molecular entities Discrete molecular entities... 

Supramolecular chemistry The basis of supramolecular chemistry is the intermolecular interaction between simple molecular entities to form more complex organized molecular entities known as supermolecules and supramolecular assemblies. The focus of supramolecular chemistry is the structural, dynamical, and functional consequences of the organization of such entities. 

Under different types of agreements, short- and long-term projects are undertaken in close alignment to customer needs. Joint projects are meant to discover and synthesize new molecular entities designed for specific functions, discovery new and more efficient approaches to the synthesis of target molecules, and characterization of components of complex organic mixtures. 

Caco-2 cells have been valuable in the estimation of drug absorption potential, transport mechanisms, and effect of permeation enhancers on transepithelial transport.35,39,53,67-69,78-81 Owing to the sensitivity of the cells and the limited solubility of new molecular entities, Caco-2 permeability studies are routinely done with relatively low concentration of compounds. One way to increase the solubility of these compounds is to use organic solvents. The low tolerability of Caco-2 cells to organic solvents limits the use of this approach in permeability studies. 

The final, purified bulk product is thoroughly characterized and compared to reference standards established by the manufacturer for new molecular entities or available from the United States Pharmacopoeia (USP) or the World Health Organization s National Institute of Biological Standards and Control. Characterization tests of proteins may include biologic potency assays, chromatographic assays, gel... 

The materials capable of stimulating the lymphoid tissues to produce antibodies are termed antigens and comprise bacterial and viruses as well as some smaller molecular entities. However, the response is not to the intact organisms but rather to some specific parts which have characteristic three-dimensional structures, the epitopes, and this sensitivity to structure is a characteristic feature of the immune response. Once an animal is in contact with an epitope the response can be in the circulatory or humoral system or directly as a cell-mediated response, but it is exquisitely sensitive to the specific antigen and rarely to any other. 

One point to address concerns the use of the words s pramolecular and supermolecule. The concept of supramolecular chemistry has become a unifying attractor, in which areas that have developed independently have spontaneously found their place. The word supramolecular has been used in particular for large multiprotein architectures and organized molecular assemblies [1.16]. On the other hand, in theoretical chemistry, the computational procedure that treats molecular associations such as the water dimer as a single entity is termed the supermolecule approach [1.34,1.35]. Taking into account the existence and the independent uses of these two words, one may then propose that supramolecular chemistry be the broader term, concerning the chemistry of all types of supramolecular entities from the well-defined supermolecules to extended, more or less organized, polymolecular associations. The term super molecular chemistry would be restricted to the specific chemistry of the supermolecules themselves. 

Endowing these polymolecular entities with recognition units and reactive functional groups may lead to systems performing molecular recognition or supramolecular catalysis on external or internal surfaces of organic (molecular layers, membranes, vesicles, polymers, etc.) [7.1-7.13, A.41] or inorganic (zeolites, clays, sol-gel preparations, etc.) [7.14-7.20] materials. 

This section describes systems which are at the border of what has been defined as being the scope of this review and therefore does not pretend to be comprehensive. Indeed, if there is a wealth of strictly inorganic materials and glasses into which NIR-crnitting lanthanide ions have been incorporated and which are clearly excluded from the review, there also exist a continuum between these materials and molecular entities, for instance coordination polymers and clusters which have been described in the two preceding sections. In continuity with these concepts are micro- and mesoporous materials into which lanthanide salts or complexes can be incorporated or attached. These are essentially zeolites and sol-gel materials, either conventional or the so-called inorganic-organic hybrids, as well as polymers. 

Finally, silica nanoparticles have been used recently as scaffolds to self-organize the sensing units or even their separate components and allow complex functions originating from the spatial organization of different molecular entities in the particle... 

Host — A - molecular entity that forms an -> inclusion complex with organic or inorganic -> guests, or a - chemical species that can accommodate guests within cavities of its crystal structure. Examples include cryptands and crowns (where there are -> ion-dipole interactions between heteroatoms and positive ions), hydrogen-bonded molecules that form clathrates (e.g., hydroquinone and water), and host molecules of inclusion compounds (e.g., urea or thiourea). The - van der Waals forces and hydrophobic interactions (- hydrophobic effect) bind the guest to the host molecule in clathrates and inclusion compounds. 

A. Candidate New chemical entity (small organic molecular)... 

A great variety of (functional) supramolecular architectures has been generated by complex self-assembly procedures, of purely organic as well as of inorganic natures [3-5, 12-17, 26-30]. The latter have led to a range of metallosupra-molecular entities presenting original structural, physical, and chemical properties. 

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