PhotodissociationPhotodissociation, photolysis, photodecomposition, or photofragmentation is a chemical reaction in which molecules of a chemical compound are broken down by photons. It is defined as the interaction of one or more photons with one target molecule. Photodissociation is not limited to visible light. Any photon with sufficient energy can affect the chemical bonds of a chemical compound. Since a photon's energy is inversely proportional to its wavelength, electromagnetic radiations with the energy of visible light or higher, such as ultraviolet light, X-rays, and gamma rays can induce such reactions.
Metal carbonylMetal carbonyls are coordination complexes of transition metals with carbon monoxide ligands. Metal carbonyls are useful in organic synthesis and as catalysts or catalyst precursors in homogeneous catalysis, such as hydroformylation and Reppe chemistry. In the Mond process, nickel tetracarbonyl is used to produce pure nickel. In organometallic chemistry, metal carbonyls serve as precursors for the preparation of other organometallic complexes.
TrimethylamineTrimethylamine (TMA) is an organic compound with the formula N(CH3)3. It is a trimethylated derivative of ammonia. TMA is widely used in industry: it is used in the synthesis of choline, tetramethylammonium hydroxide, plant growth regulators or herbicides, strongly basic anion exchange resins, dye leveling agents, and a number of basic dyes. At higher concentrations it has an ammonia-like odor, and can cause necrosis of mucous membranes on contact. At lower concentrations, it has a "fishy" odor, the odor associated with rotting fish.
Anfinsen's dogmaAnfinsen's dogma, also known as the thermodynamic hypothesis, is a postulate in molecular biology. It states that, at least for a small globular protein in its standard physiological environment, the native structure is determined only by the protein's amino acid sequence. The dogma was championed by the Nobel Prize Laureate Christian B. Anfinsen from his research on the folding of ribonuclease A. The postulate amounts to saying that, at the environmental conditions (temperature, solvent concentration and composition, etc.
Threatened speciesThreatened species are any species (including animals, plants and fungi) which are vulnerable to extinction in the near future. Species that are threatened are sometimes characterised by the population dynamics measure of critical depensation, a mathematical measure of biomass related to population growth rate. This quantitative metric is one method of evaluating the degree of endangerment.
CryptandIn chemistry, cryptands are a family of synthetic, bicyclic and polycyclic, multidentate ligands for a variety of cations. The Nobel Prize for Chemistry in 1987 was given to Donald J. Cram, Jean-Marie Lehn, and Charles J. Pedersen for their efforts in discovering and determining uses of cryptands and crown ethers, thus launching the now flourishing field of supramolecular chemistry. The term cryptand implies that this ligand binds substrates in a crypt, interring the guest as in a burial.
