Molecules/Elements/Particles

 

Thursday
Oct202011

Chlorofluorocarbons

"A chlorofluorocarbon (CFC) is an organic compound that contains carbon, chlorine, and fluorine, produced as a volatile derivative of methane and ethane. A common subclass are the hydrochlorofluorocarbons (HCFCs), which contain hydrogen, as well. They are also commonly known by the DuPont trade name Freon. The most common representative is dichlorodifluoromethane (R-12 or Freon-12). Many CFCs have been widely used as refrigerants, propellants (in aerosol applications), and solvents. The manufacture of such compounds is being phased out by the Montreal Protocol because they contribute to ozone depletion."

Wednesday
Oct192011

Polybutadiene

"Polybutadiene is a synthetic rubber that is a polymer formed from the polymerization process of the monomer 1,3-butadiene."

"It has a high resistance to wear and is used especially in the manufacture of tires, which consumes about 70% of the production. Another 25% is used as an additive to improve the mechanical strength of plastics such as polystyrene and acrylonitrile butadiene styrene (ABS). It is also used to manufacture golf balls, various elastic objects and to coat or encapsulate electronic assemblies, offering extremely high electrical resistivity. It exhibits a recovery of 80% after stress is applied, a value only exceeded by elastin and resilin."

Tuesday
Oct182011

Cysteine

"Cysteine (abbreviated as Cys or C)[3] is an α-amino acid with the chemical formula HO2CCH(NH2)CH2SH. It is a non-essential amino acid, which means that it is biosynthesized in humans. Its codons are UGU and UGC. The side chain on cysteine is thiol, which is polar and thus cysteine is usually classified as a hydrophilic amino acid.[4] The thiol side chain often participates in enzymatic reactions, serving as a nucleophile. The thiol is susceptible to oxidization to give the disulfide derivative cystine, which serves an important structural role in many proteins."

 

Monday
Oct172011

Putrescine

"Putrescine (sometimes spelled putrescin) is a foul-smelling [1] organic chemical compound NH2(CH2)4NH2 (1,4-diaminobutane or butanediamine) that is related to cadaverine; both are produced by the breakdown of amino acids in living and dead organisms and both are toxic in large doses.[2][3] The two compounds are largely responsible for the foul odor of putrefying flesh, but also contribute to the odor of such processes as bad breath and bacterial vaginosis. They are also found in semen and some microalgae, together with related molecules like spermine and spermidine."

Saturday
Oct152011

Benzaldehyde

"Benzaldehyde (C6H5CHO) is an organic compound consisting of a benzene ring with a formyl substituent. It is the simplest aromatic aldehyde and one of the most industrially useful. This colorless liquid has a characteristic pleasant almond-like odor. In fact, benzaldehyde is the primary component of bitter almond oil and can be extracted from a number of other natural sources.[1]"

"Almonds, apricots, apples and cherry kernels, contain significant amounts of amygdalin. This glycoside breaks up under enzyme catalysis into benzaldehyde, hydrocyanic acid and two molecules of glucose:"

amygdalin
Friday
Oct142011

Retinal

"Retinal is an interesting molecule because it is the reason we are able to see. Or at least one of them. Retinal, or more correctly, 11-cis-retinal, is a small molecule which fits into the binding site of a large protein called opsin. Together they make up rhodopsin (also known as 'visual purple', the structure of which is shown below. This is where the terms 'rods' (think Rhodopsin) and 'cones' come from, referring to cells in the retina of our eyes which contain rhodosin and isodoposin pigments, respectively."

"Retinal comes in two forms, 11-cis- and all-trans. The -cis prefix comes from the fact that one of the double bonds (at the 11th carbon) has the two largest substituents (that is, the largest chains coming off it) on the same side. The other double bonds are all -trans, or with the bulky substituents positioned on opposite sides. A more modern nomenclature uses the letters E (from the German, entgegen; apart) and Z (from zusammen; together). The trans- (E) version is long and straight, whereas the cis- (Z) version is bent in two."

cis-retinal - click for 3D structure all-trans-retinal - click for 3D structure

"

Thursday
Oct132011

Diethyl Ether

"The compound may have been created by either Jābir ibn Hayyān in the 8th century[2] or Raymundus Lullus in 1275[2][3], although there is no contemporary evidence of this. It was first synthesized in 1540 by Valerius Cordus and , who called it "sweet oil of vitriol" (oleum dulce vitrioli)—the name reflects the fact that it is obtained by distilling a mixture of ethanol and sulfuric acid (then known as oil of vitriol)—and noted some of its medicinal properties.[2] At about the same time, Theophrastus Bombastus von Hohenheim, better known as Paracelsus, discovered ether's analgesic properties in chickens.[2] The name ether was given to the substance in 1730 by August Siegmund Frobenius."

Tuesday
Oct112011

Ethyl Acetate

"Ethyl acetate (systematically, ethyl ethanoate, commonly abbreviated EtOAc or EA) is the organic compound with the formula CH3COOCH2CH3. This colorless liquid has a characteristic sweet smell (similar to pear drops) and is used in glues, nail polish removers, and cigarettes (see list of additives in cigarettes). Ethyl acetate is the ester of ethanol and acetic acid; it is manufactured on a large scale for use as a solvent. The combined annual production in 1985 of Japan, North America, and Europe was about 400,000 tons.[1] In 2004, an estimated 1.3M tons were produced worldwide.[2]"

Monday
Oct102011

Myoglobin

"Myoglobin is an iron- and oxygen-binding protein found in the muscle tissue of vertebrates in general and in almost all mammals. It is related to hemoglobin, which is the iron- and oxygen-binding protein in blood, specifically in the red blood cells. The only time myoglobin is found in the bloodstream is when it is released following muscle injury. It is an abnormal finding, and can be diagnostically relevant when found in blood. [2]"

"Myoglobin (abbreviated Mb) is a single-chain globular protein of 153[3] or 154[4] amino acids, containing a heme (iron-containing porphyrin) prosthetic group in the center around which the remaining apoprotein folds. It has eight alpha helices and a hydrophobic core. It has a molecular weight of 17,699 (with heme)daltons, and is the primary oxygen-carrying pigment of muscle tissues.[4] Unlike the blood-borne hemoglobin, to which it is structurally related,[5] this protein does not exhibit cooperative binding of oxygen, since positive cooperativity is a property of multimeric/oligomeric proteins only. Instead, the binding of oxygen by myoglobin is unaffected by the oxygen pressure in the surrounding tissue. Myoglobin is often cited as having an "instant binding tenacity" to oxygen given its hyperbolic oxygen dissociation curve. High concentrations of myoglobin in muscle cells allow organisms to hold their breaths longer. Diving mammals such as whales and seals have muscles with particularly high myoglobin abundance.[2]"

Sunday
Oct092011

Carbon Nanotubes

Carbon nanotubes (CNTs) are allotropes of carbon with a cylindrical nanostructure. Nanotubes have been constructed with length-to-diameter ratio of up to 132,000,000:1,[1] significantly larger than for any other material. These cylindrical carbon molecules have unusual properties, which are valuable for nanotechnology, electronics, optics and other fields of materials science and technology. In particular, owing to their extraordinary thermal conductivity and mechanical and electrical properties, carbon nanotubes may find applications as additives to various structural materials.

Nanotubes are members of the fullerene structural family, which also includes the spherical buckyballs, and the ends of a nanotube may be capped with a hemisphere of the buckyball structure. Their name is derived from their long, hollow structure with the walls formed by one-atom-thick sheets of carbon, called graphene. These sheets are rolled at specific and discrete ("chiral") angles, and the combination of the rolling angle and radius decides the nanotube properties; for example, whether the individual nanotube shell is a metal or semiconductor. Nanotubes are categorized as single-walled nanotubes (SWNTs) and multi-walled nanotubes (MWNTs). Individual nanotubes naturally align themselves into "ropes" held together by van der Waals forces.