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Trimethylamine N-oxide
Trimethylamine ''N''-oxide (TMAO) is an organic compound with the formula . It is in the class of amine oxides. Although the anhydrous compound is known, trimethylamine ''N''-oxide is usually encountered as the dihydrate. Both the anhydrous and hydrated materials are white, water-soluble solids. TMAO is found in the tissues of marine crustaceans and marine fish, where it prevents water pressure from distorting proteins and thus killing the animal. The concentration of TMAO increases with the depth at which the animal lives; TMAO is found in high concentrations in the deepest-living described fish species, '' Pseudoliparis swirei'', which was found in the Mariana Trench, at a recorded depth of . In animals, TMAO is a product of the oxidation of trimethylamine, a common metabolite of trimethyl quaternary ammonium compounds, like choline, trimethylglycine, and L-carnitine. High TMAO concentrations are associated with an increased risk of all-cause mortality and cardiovascular di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Debye
The debye ( , ; symbol: D) is a CGS unit (a non- SI metric unit) of electric dipole momentTwo equal and opposite charges separated by some distance constitute an electric dipole. This dipole possesses an electric dipole moment whose value is given as charge times length of separation. The dipole itself is a vector whose direction coincides with the position vector of the positive charge with respect to the negative charge: : p = ''q''r. named in honour of the physicist Peter J. W. Debye. It is defined as statcoulomb-centimetres.The statcoulomb is also known as the franklin or electrostatic unit of charge. : 1 statC = 1 Fr = 1 esu = 1 cm3/2⋅g1/2⋅s−1. Historically the debye was defined as the dipole moment resulting from two charges of opposite sign but an equal magnitude of 10−10 statcoulomb10−10 statcoulomb corresponds to approximately 0.2083 units of elementary charge. (generally called e.s.u. (electrostatic unit) in ol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fish As Food
Many species of fish are caught by humans and consumed as food in virtually all regions around the world. Their meat has been an important dietary source of protein and other nutrients in the human diet. The English language does not have a special culinary name for food prepared from fish like with other animals (as with '' pig'' vs. ''pork''), or as in other languages (such as Spanish '' pez'' vs. '' pescado''). In culinary and fishery contexts, ''fish'' may include so-called shellfish such as molluscs, crustaceans, and echinoderms; but, more expansively, ''seafood'' covers both fish and other marine life used as food. Since 1961, the average annual increase in global apparent food fish consumption (3.2 percent) has outpaced population growth (1.6 percent) and exceeded the increase in consumption of meat from all terrestrial animals except poultry (4.9 percent), both combined (2.8 percent) and individually (bovine, ovine, porcine, et cetera). In ''per capita'' terms, f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ligands
In coordination chemistry, a ligand is an ion or molecule with a functional group that binds to a central metal atom to form a coordination complex. The bonding with the metal generally involves formal donation of one or more of the ligand's electron pairs, often through Lewis bases. The nature of metal–ligand bonding can range from covalent to ionic. Furthermore, the metal–ligand bond order can range from one to three. Ligands are viewed as Lewis bases, although rare cases are known to involve Lewis acidic "ligands". Metals and metalloids are bound to ligands in almost all circumstances, although gaseous "naked" metal ions can be generated in a high vacuum. Ligands in a complex dictate the reactivity of the central atom, including ligand substitution rates, the reactivity of the ligands themselves, and redox. Ligand selection requires critical consideration in many practical areas, including bioinorganic and medicinal chemistry, homogeneous catalysis, and environme ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ligand
In coordination chemistry, a ligand is an ion or molecule with a functional group that binds to a central metal atom to form a coordination complex. The bonding with the metal generally involves formal donation of one or more of the ligand's electron pairs, often through Lewis acids and bases, Lewis bases. The nature of metal–ligand bonding can range from covalent bond, covalent to ionic bond, ionic. Furthermore, the metal–ligand bond order can range from one to three. Ligands are viewed as Lewis bases, although rare cases are known to involve Lewis acids and bases, Lewis acidic "ligands". Metals and metalloids are bound to ligands in almost all circumstances, although gaseous "naked" metal ions can be generated in a high vacuum. Ligands in a complex dictate the reactivity (chemistry), reactivity of the central atom, including ligand substitution rates, the reactivity of the ligands themselves, and redox. Ligand selection requires critical consideration in many practical are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metal Carbonyl
A metal () is a material that, when polished or fractured, shows a lustrous appearance, and conducts electricity and heat relatively well. These properties are all associated with having electrons available at the Fermi level, as against nonmetallic materials which do not. Metals are typically ductile (can be drawn into a wire) and malleable (can be shaped via hammering or pressing). A metal may be a chemical element such as iron; an alloy such as stainless steel; or a molecular compound such as polymeric sulfur nitride. The general science of metals is called metallurgy, a subtopic of materials science; aspects of the electronic and thermal properties are also within the scope of condensed matter physics and solid-state chemistry, it is a multidisciplinary topic. In colloquial use materials such as steel alloys are referred to as metals, while others such as polymers, wood or ceramics are nonmetallic materials. A metal conducts electricity at a temperature of absolu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stoichiometry
Stoichiometry () is the relationships between the masses of reactants and Product (chemistry), products before, during, and following chemical reactions. Stoichiometry is based on the law of conservation of mass; the total mass of reactants must equal the total mass of products, so the relationship between reactants and products must form a ratio of positive integers. This means that if the amounts of the separate reactants are known, then the amount of the product can be calculated. Conversely, if one reactant has a known quantity and the quantity of the products can be empirically determined, then the amount of the other reactants can also be calculated. This is illustrated in the image here, where the unbalanced equation is: : : However, the current equation is imbalanced. The reactants have 4 hydrogen and 2 oxygen atoms, while the product has 2 hydrogen and 3 oxygen. To balance the hydrogen, a coefficient of 2 is added to the product H2O, and to fix the imbalance of oxygen, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Decarbonylation
In chemistry, decarbonylation is a type of organic reaction that involves the loss of carbon monoxide (CO). It is often an undesirable reaction, since it represents a degradation. In the chemistry of metal carbonyls, decarbonylation describes a substitution process, whereby a CO ligand is replaced by another ligand. Organic chemistry In the absence of metal catalysts, decarbonylation (vs decarboxylation) is rarely observed in organic chemistry Organic chemistry is a subdiscipline within chemistry involving the science, scientific study of the structure, properties, and reactions of organic compounds and organic matter, organic materials, i.e., matter in its various forms that contain .... One exception is the decarbonylation of formic acid: :HOH → + The reaction is induced by sulfuric acid, which functions as both a catalyst and a Dehydration reaction, dehydrating agent. Via this reaction, formic acid is occasionally employed as a source of CO in the laboratory in l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nucleophilic Abstraction
Nucleophilic abstraction is a type of an organometallic reaction which can be defined as a nucleophilic attack on a ligand which causes part or all of the original ligand to be removed from the metal along with the nucleophile.Spessard, Gary; Miessler, Gary (2010).''Organometallic Chemistry: Second Edition''. pp. 285-289 Alkyl abstraction While nucleophilic abstraction of an alkyl group is relatively uncommon, there are examples of this type of reaction. In order for this reaction to be favorable, the metal must first be oxidized because reduced metals are often poor leaving groups. The oxidation of the metal causes the M-C bond to weaken, which allows for the nucleophilic abstraction to occur. G.M. Whitesides and D.J. Boschetto use the halogens Br2 and I2 as M-C cleaving agents in the following example of nucleophilic abstraction. It is important to note that the product of this reaction is inverted with respect to the stereochemical center attached to the metal. There ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organometallic Chemistry
Organometallic chemistry is the study of organometallic compounds, chemical compounds containing at least one chemical bond between a carbon atom of an organic molecule and a metal, including alkali, alkaline earth, and transition metals, and sometimes broadened to include metalloids like boron, silicon, and selenium, as well. Aside from bonds to organyl fragments or molecules, bonds to 'inorganic' carbon, like carbon monoxide (Metal carbonyl, metal carbonyls), cyanide, or carbide, are generally considered to be organometallic as well. Some related compounds such as transition metal hydrides and metal phosphine complexes are often included in discussions of organometallic compounds, though strictly speaking, they are not necessarily organometallic. The related but distinct term "metalorganics, metalorganic compound" refers to metal-containing compounds lacking direct metal-carbon bonds but which contain organic ligands. Metal β-diketonates, alkoxides, dialkylamides, and metal p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Urea
Urea, also called carbamide (because it is a diamide of carbonic acid), is an organic compound with chemical formula . This amide has two Amine, amino groups (–) joined by a carbonyl functional group (–C(=O)–). It is thus the simplest amide of carbamic acid. Urea serves an important role in the cellular metabolism of nitrogen-containing compounds by animals and is the main nitrogen-containing substance in the urine of mammals. ''Urea'' is Neo-Latin, , , itself from Proto-Indo-European ''*h₂worsom''. It is a colorless, odorless solid, highly soluble in water, and practically non-toxic ( is 15 g/kg for rats). Dissolved in water, it is neither acidic nor base (chemistry), alkaline. The body uses it in many processes, most notably metabolic waste#Nitrogen wastes, nitrogen excretion. The liver forms it by combining two ammonia molecules () with a carbon dioxide () molecule in the urea cycle. Urea is widely used in fertilizers as a source of nitrogen (N) and is an important ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein Folding
Protein folding is the physical process by which a protein, after Protein biosynthesis, synthesis by a ribosome as a linear chain of Amino acid, amino acids, changes from an unstable random coil into a more ordered protein tertiary structure, three-dimensional structure. This structure permits the protein to become biologically functional or active. The folding of many proteins begins even during the translation of the polypeptide chain. The amino acids interact with each other to produce a well-defined three-dimensional structure, known as the protein's native state. This structure is determined by the amino-acid sequence or primary structure. The correct three-dimensional structure is essential to function, although some parts of functional proteins Intrinsically unstructured proteins, may remain unfolded, indicating that protein dynamics are important. Failure to fold into a native structure generally produces inactive proteins, but in some instances, misfolded proteins have ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dimethylformamide
Dimethylformamide, DMF is an organic compound with the chemical formula . Its structure is . Commonly abbreviated as DMF (although this initialism is sometimes used for 2,5-dimethylfuran, dimethylfuran, or dimethyl fumarate), this colourless liquid is Miscibility, miscible with Water (molecule), water and the majority of organic liquids. DMF is a common solvent for chemical reactions. Dimethylformamide is odorless, but chemical purity, technical-grade or degraded samples often have a fishy smell due to impurity of dimethylamine. Dimethylamine degradation impurities can be removed by Sparging (chemistry), sparging samples with an inert gas such as argon or by sonication, sonicating the samples under reduced pressure. As its name indicates, it is structurally related to formamide, having two methyl groups in the place of the two hydrogens. DMF is a polar molecule, polar (hydrophilic) aprotic solvent with a high boiling point. It facilitates reactions that follow polar mechanisms, such ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
