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Metallaprism
Coordination cages are three-dimensional ordered structures in solution that act as hosts in host–guest chemistry. They are self-assembled in solution from organometallic precursors, and often rely solely on noncovalent interactions rather than covalent bonds. Coordinate bonds are useful in such supramolecular self-assembly because of their versatile geometries. However, there is controversy over calling coordinate bonds noncovalent, as they are typically strong bonds and have covalent character. The combination of a coordination cage and a guest is a type of inclusion compound. Coordination complexes can be used as "nano-laboratories" for synthesis, and to isolate interesting intermediates. The inclusion complexes of a guest inside a coordination cage show intriguing chemistry as well; often, the properties of the cage will change depending on the guest. Coordination complexes are molecular moieties, so they are distinct from clathrates and metal-organic frameworks. History Chemis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Host–guest Chemistry
In supramolecular chemistry, host–guest chemistry describes inclusion compound, complexes that are composed of two or more molecules or ions that are held together in unique structural relationships by forces other than those of full covalent bonds. Host–guest chemistry encompasses the idea of molecular recognition and interactions through non-covalent bonding. Non-covalent bonding is critical in maintaining the 3D structure of large molecules, such as proteins, and is involved in many biological processes in which large molecules bind specifically but transiently to one another. Although non-covalent interactions could be roughly divided into those with more electrostatic or dispersive contributions, there are few commonly mentioned types of non-covalent interactions: ionic bonding, hydrogen bonding, van der Waals forces and hydrophobic effect, hydrophobic interactions. Host-guest interaction has raised significant attention since it was discovered. It is an important field b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyridine
Pyridine is a basic (chemistry), basic heterocyclic compound, heterocyclic organic compound with the chemical formula . It is structurally related to benzene, with one methine group replaced by a nitrogen atom . It is a highly flammable, weakly alkaline, water-miscible liquid with a distinctive, unpleasant fish-like smell. Pyridine is colorless, but older or impure samples can appear yellow, due to the formation of extended, unsaturated Polymer, polymeric chains, which show significant electrical conductivity. The pyridine ring occurs in many important compounds, including agrochemicals, pharmaceuticals, and vitamins. Historically, pyridine was produced from coal tar. As of 2016, it is synthesized on the scale of about 20,000 tons per year worldwide. Properties Physical properties Pyridine is diamagnetism, diamagnetic. Its critical point (thermodynamics), critical parameters are: pressure 5.63 MPa, temperature 619 K and volume 248 cm3/mol. In the temperatur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metal Complexes
A coordination complex is a chemical compound consisting of a central atom or ion, which is usually metallic and is called the ''coordination centre'', and a surrounding array of bound molecules or ions, that are in turn known as ''ligands'' or complexing agents. Many metal-containing compounds, especially those that include transition metals (elements like titanium that belong to the periodic table's d-block), are coordination complexes. Nomenclature and terminology Coordination complexes are so pervasive that their structures and reactions are described in many ways, sometimes confusingly. The atom within a ligand that is bonded to the central metal atom or ion is called the donor atom. In a typical complex, a metal ion is bonded to several donor atoms, which can be the same or different. A polydentate (multiple bonded) ligand is a molecule or ion that bonds to the central atom through several of the ligand's atoms; ligands with 2, 3, 4 or even 6 bonds to the central ato ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Derivative (chemistry)
In chemistry, a derivative is a compound that is derived from a similar compound by a chemical reaction. In the past, derivative also meant a compound that ''can be imagined to'' arise from another compound, if one atom or group of atoms is replaced with another atom or group of atoms, but modern chemical language now uses the term structural analog for this meaning, thus eliminating ambiguity. The term "structural analogue" is common in organic chemistry. In biochemistry, the word is used for compounds that at least theoretically can be formed from the precursor compound. Chemical derivatives may be used to facilitate analysis. For example, melting point (MP) analysis can assist in identification of many organic compounds. A crystalline derivative may be prepared, such as a semicarbazone or 2,4-dinitrophenylhydrazone (derived from aldehydes or ketones), as a simple way of verifying the identity of the original compound, assuming that a table of derivative MP values is avai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bioconjugate
Bioconjugation is a chemical strategy to form a stable covalent link between two molecules, at least one of which is a biomolecule. Methods to conjugate biomolecules are applied in various field, including medicine, diagnostics, biocatalysis and materials. Synthetically modified biomolecules can have diverse functionalities, such as tracking cellular events, revealing enzyme function, determining protein biodistribution, imaging specific biomarkers, and delivering drugs to targeted cells. Bioconjugation is a crucial strategy that links these modified biomolecules with different substrates. Besides applications in biomedical research, bioconjugation has recently also gained importance in nanotechnology such as bioconjugated quantum dots. The most common types of bioconjugation include coupling of a small molecule (such as biotin or a fluorescent dye) to a protein. Antibody-drug conjugates such as Brentuximab vedotin and Gemtuzumab ozogamicin are examples falling into this ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triazine
Triazines are a class of nitrogen-containing heterocycles. The parent molecules' molecular formula is . They exist in three isomeric forms, 1,3,5-triazines being common. Structure The triazines have planar six-membered benzene-like ring but with three carbons replaced by nitrogens. The three isomers of triazine are distinguished by the positions of their nitrogen atoms, and are referred to as 1,2,3-triazine, 1,2,4-triazine, and 1,3,5-triazine. Other aromatic nitrogen heterocycles are pyridines with one ring nitrogen atom, diazines with 2 nitrogen atoms in the ring, triazoles with 3 nitrogens in a 5-membered ring, and tetrazines with 4 ring nitrogen atoms. Uses Melamine A well known triazine is melamine (2,4,6-triamino-1,3,5-triazine). With three amino substituents, melamine is a precursor to commercial resins. Guanamines are closely related to melamine, except with one amino substituent replaced by an organic group. This difference is exploited in the use of guanamine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molecular Self-assembly
In chemistry and materials science, molecular self-assembly is the process by which molecules adopt a defined arrangement without guidance or management from an outside source. There are two types of self-assembly: intermolecular and intramolecular. Commonly, the term ''molecular self-assembly'' refers to the former, while the latter is more commonly called '' folding''. Supramolecular systems Molecular self-assembly is a key concept in supramolecular chemistry. This is because assembly of molecules in such systems is directed through non-covalent interactions (e.g., hydrogen bonding, metal coordination, hydrophobic forces, van der Waals forces, pi-stacking interactions, and/or electrostatic) as well as electromagnetic interactions. Common examples include the formation of colloids, biomolecular condensates, micelles, vesicles, liquid crystal phases, and Langmuir monolayers by surfactant molecules. Further examples of supramolecular assemblies demonstrate that a variety ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemical Synthesis
Chemical synthesis (chemical combination) is the artificial execution of chemical reactions to obtain one or several products. This occurs by physical and chemical manipulations usually involving one or more reactions. In modern laboratory uses, the process is reproducible and reliable. A chemical synthesis involves one or more compounds (known as '' reagents'' or ''reactants'') that will experience a transformation under certain conditions. Various reaction types can be applied to formulate a desired product. This requires mixing the compounds in a reaction vessel, such as a chemical reactor or a simple round-bottom flask. Many reactions require some form of processing (" work-up") or purification procedure to isolate the final product. The amount produced by chemical synthesis is known as the '' reaction yield''. Typically, yields are expressed as a mass in grams (in a laboratory setting) or as a percentage of the total theoretical quantity that could be produced based ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
