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Thioketone
In organic chemistry, thioketones (; also known as thiones or thiocarbonyls) are organosulfur compounds related to conventional ketones in which the oxygen has been replaced by a sulfur. Instead of a structure of , thioketones have the structure , which is reflected by the prefix " thio-" in the name of the functional group. Thus the simplest thioketone is thioacetone, the sulfur analog of acetone. Unhindered alkylthioketones typically tend to form polymers or rings. Structure and bonding The C=S bond length of thiobenzophenone is 1.63 Å, which is comparable to 1.64 Å, the C=S bond length of thioformaldehyde, measured in the gas phase. Due to steric interactions, the phenyl groups are not coplanar and the dihedral angle SC-CC is 36°. Unhindered dialkylthiones polymerize or oligomerize but thiocamphor is well characterized red solid. Consistent with the double bond rule, most alkyl thioketones are unstable with respect to dimerization.Organosulfur Chemistry I: Topics in Cur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organosulfur Compound
Organosulfur chemistry is the study of the properties and synthesis of organosulfur compounds, which are organic compounds that contain sulfur. They are often associated with foul odors, but many of the sweetest compounds known are organosulfur derivatives, e.g., saccharin. Nature is abound with organosulfur compounds—sulfur is vital for life. Of the 20 common amino acids, two ( cysteine and methionine) are organosulfur compounds, and the antibiotics penicillin and sulfa drugs both contain sulfur. While sulfur-containing antibiotics save many lives, sulfur mustard is a deadly chemical warfare agent. Fossil fuels, coal, petroleum, and natural gas, which are derived from ancient organisms, necessarily contain organosulfur compounds, the removal of which is a major focus of oil refineries. Sulfur shares the chalcogen group with oxygen, selenium, and tellurium, and it is expected that organosulfur compounds have similarities with carbon–oxygen, carbon–selenium, and car ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bis(trimethylsilyl)sulfide
Bis(trimethylsilyl) sulfide is the chemical compound with the formula ((CH3)3Si)2S. Often abbreviated ( tms)2S, this colourless, vile-smelling liquid is a useful aprotic source of "S2−" in chemical synthesis. Synthesis The reagent is prepared by treating trimethylsilyl chloride with anhydrous sodium sulfide: :2 (CH3)3SiCl + Na2S → ((CH3)3Si)2S + 2 NaCl ((CH3)3Si)2S must be protected from air because it hydrolyzes readily: :((CH3)3Si)2S + H2O → ((CH3)3Si)2O + H2S Use in synthesis Bis(trimethylsilyl)sulfide is a reagent for the conversion of metal oxides and chlorides into the corresponding sulfides. This transformation exploits the affinity of silicon(IV) for oxygen and halides. An idealized reaction is: :((CH3)3Si)2S + MO → ((CH3)3Si)2O + MS In a similar way, it has been used in the conversion of aldehydes and ketones to the corresponding thiones. Safety ((CH3)3Si)2S reacts exothermic In thermodynamics, an exothermic process () is a thermodyn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ketone
In organic chemistry, a ketone is an organic compound with the structure , where R and R' can be a variety of carbon-containing substituents. Ketones contain a carbonyl group (a carbon-oxygen double bond C=O). The simplest ketone is acetone (where R and R' are methyl), with the formula . Many ketones are of great importance in biology and industry. Examples include many sugars (ketoses), many steroids, ''e.g.'', testosterone, and the solvent acetone. Nomenclature and etymology The word ''ketone'' is derived from ''Aketon'', an old German word for ''acetone''. According to the rules of IUPAC nomenclature, ketone names are derived by changing the suffix ''-ane'' of the parent alkane to ''-anone''. Typically, the position of the carbonyl group is denoted by a number, but traditional nonsystematic names are still generally used for the most important ketones, for example acetone and benzophenone. These nonsystematic names are considered retained IUPAC names, although some introdu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thio-
The prefix thio-, when applied to a chemical, such as an ion, means that an oxygen atom in the compound has been replaced by a sulfur atom. This term is often used in organic chemistry. For example, from the word ''ether,'' referring to an oxygen-containing compound having the general chemical structure , where R and R′ are organic functional groups and O is an oxygen atom, comes the word ''thioether'', which refers to an analogous compound with the general structure , where S is a sulfur atom covalently bonded to two organic groups. A chemical reaction involving the replacement of oxygen to sulfur is called thionation or thiation. Thio- can be prefixed with ''di-'' and ''tri-'' in chemical nomenclature. The word derives (which occurs in Greek epic poetry as and may come from the same root as Latin (Indo-European ''dh-w'') and may have originally meant " fumigation substance".) Examples * Thioamide * Thiocyanate * Thioether * Thioketone * Thiol * Thiophene * Thiourea * T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thioacetone
Thioacetone is an organosulfur compound belonging to the -thione group called thioketones with a chemical formula (CH3)2CS. It is an unstable orange or brown substance that can be isolated only at low temperatures. Above , thioacetone readily converts to a polymer and a trimer, trithioacetone. It has an extremely potent, unpleasant odor, and is considered one of the worst-smelling substances known. Thioacetone was first obtained in 1889 by Baumann and Fromm, as a minor impurity in their synthesis of trithioacetone. Preparation Thioacetone is usually obtained by cracking the cyclic trimer trithioacetone, CH3)2CSsub>3. The trimer is prepared by pyrolysis of allyl isopropyl sulfide or by treating acetone with hydrogen sulfide in the presence of a Lewis acid. The trimer cracks at to give the thione. : Polymerization Unlike its oxygen analogue acetone, which does not polymerise easily, thioacetone spontaneously polymerizes even at very low temperatures, pure or dissolved in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ph2CS
Thiobenzophenone is an organosulfur compound with the formula (C6H5)2CS. It is the prototypical thioketone. Unlike other thioketones that tend to dimerize to form rings and polymers, thiobenzophenone is quite stable, although it photoxidizes in air back to benzophenone and sulfur. Thiobenzophenone is deep blue and dissolves readily in many organic solvents. Structure The C=S bond length of thiobenzophenone is 1.63 Å, which is comparable to 1.64 Å, the C=S bond length of thioformaldehyde, measured in the gas phase. Due to steric interactions, the phenyl groups are not coplanar and the dihedral angle SC-CC is 36°.Sustmann, R.; Sicking, W.; Huisgen, R. "A Computational Study of the Cycloaddition of Thiobenzophenone S-Methylide to Thiobenzophenone". J. Am. Chem. Soc. 2003, 125, 14425-14434. A variety of thiones with structures and stability related to thiobenzophenone have also been prepared. Synthesis One of the first reported syntheses of thiobenzophenone involves the reaction ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dithiirane
In organic chemistry, an episulfide is an organic compound that contain a saturated, heterocyclic ring consisting of two carbon atoms and one sulfur atom. It is the sulfur analogue of an epoxide or aziridine. They are also known as thiiranes, olefin sulfides, thioalkylene oxides, and thiacyclopropanes. Episulfides are less common and generally less stable than epoxides. The most common derivative is ethylene sulfide (). Structure According to electron diffraction, the and distances in ethylene sulfide are respectively 1.473 and 1.811 Å. The and angles are respectively 66.0 and 48.0°. Preparation History A number of chemists in the early 1900s, including Staudinger and Pfenninger (1916), as well as Delepine (1920) studied episulfides.Sander, M. Thiiranes. Chem. Rev. 1966, 66(3), 297-339. In 1934 Dachlauer and Jackel devised a general synthesis of episulfides from epoxides using alkali thiocyanates and thiourea. Contemporary methods Following the lead of Dachlaue ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1,3-dipole
In organic chemistry, a 1,3-dipolar compound or 1,3-dipole is a dipolar compound with delocalized electrons and a separation of charge over three atoms. They are reactants in 1,3-dipolar cycloadditions. The dipole has at least one resonance structure with positive and negative charges having a 1,3 relationship which can generally be denoted as , where a may be a carbon, oxygen or nitrogen, b may be nitrogen or oxygen, and c may be a carbon, oxygen or nitrogen. Known 1,3-dipoles are: * Azides () * Ozone () * Nitro compounds () * Diazo compounds () * Some oxides ** Azoxide compounds (RN(O)NR) ** Carbonyl oxides ( Criegee zwitterions)Li, Jie Jack''Criegee mechanism of ozonolysis''Book: Name Reactions. 2006, 173-174, ** Nitrile oxides () ** Nitrous oxide () ** Nitrones () * Some imines: ** Azomethine imine ** Nitrilimines (, analogous to nitrile oxide) ** Carbonyl imines * Some ylide An ylide () or ylid () is a neutral dipolar molecule containing a formally negatively c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrogen Sulfide
Hydrogen sulfide is a chemical compound with the formula . It is a colorless chalcogen-hydride gas, and is toxic, corrosive, and flammable. Trace amounts in ambient atmosphere have a characteristic foul odor of rotten eggs. Swedish chemist Carl Wilhelm Scheele is credited with having discovered the chemical composition of purified hydrogen sulfide in 1777. Hydrogen sulfide is toxic to humans and most other animals by inhibiting cellular respiration in a manner similar to hydrogen cyanide. When it is inhaled or its salts are ingested in high amounts, damage to organs occurs rapidly with symptoms ranging from breathing difficulties to convulsions and death. Despite this, the human body produces small amounts of this sulfide and its mineral salts, and uses it as a signalling molecule. Hydrogen sulfide is often produced from the microbial breakdown of organic matter in the absence of oxygen, such as in swamps and sewers; this process is commonly known as anaerobic digestio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
