Chembox verifiedrevid 430723925 ImageFile Tetraaminoethylene.svg ImageSize 120px SystematicName Ethene 1,1,2,2 tetramine ref Cite web url http pubchem.ncbi.nlm.nih.gov summary summary.cgi?cid 17899866&loc ec rcs title CID 17899866 PubChem Public Chemical Database work The PubChem Project location USA publisher National Center for Biotechnology Information ref OtherNames Ethylenetetraamine Section1 Chembox Identifiers CASNo 4363 45 5 CASNo Ref cascite correct CAS PubChem 17899866 PubChem Ref Pubchemcite correct pubchem ChemSpiderID 11487764 ChemSpiderID Ref chemspidercite correct chemspider SMILES NC N C N N StdInChI Ref stdinchicite correct chemspider StdInChI 1S C2H8N4 c3 1 4 2 5 6 h3 6H2 StdInChIKey Ref stdinchicite correct chemspider StdInChIKey XXWSZMQKQLNDLC UHFFFAOYSA N Section2 Chembox Properties C 2 H 8 N 4 ExactMass 88.074896276 g mol sup 1 sup Tetraaminoethylene is a hypothetical organic compound with formula C sub 2 sub N sub 4 sub H sub 8 sub or H sub 2 sub N sub 2 sub C C NH sub 2 sub sub 2 sub . Like all geminal polyamine s, this compound has never been synthesised and is believed to be extremely unstable. ref name lawr Stephen A. Lawrence 2004 , http books.google.com books?id 35xwBwjhe2MC&pg PA64&dq polyamines Amines synthesis, properties and applications . Cambridge University Press. ISBN 0521782848, 371 pages. ref However, there are many stable compounds that can be viewed as derivatives of tetraaminoethylene, with various organic functional groups substituted for some or all hydrogen atoms. These compounds, which have the general formula R sub 2 sub N sub 2 sub C C NR sub 2 sub sub 2 sub , are collectively called tetraaminoethylenes . Image Ethylenetetraamine.png thumb left 120px General chemical structure of tetraaminoethylene derivatives clear left Tetraaminoethylenes are important in organic chemistry as Dimer chemistry dimers of diaminocarbene s, a type of stable carbene with the general formula R sub 2 sub N sub 2 sub C . Reactions Tetraaminoe ... more details
pages 2055 doi 10.1021 ja01087a040 issue 9 ref They heated together two tetraaminoethylene derivatives ... by considering the reactivity of the electron rich tetraaminoethylene s and not the stable carbenes ... 600px Lemal s mechanism for the reaction of tetraaminoethylene with electrophiles. In conditions of excess ... believed that the tetraaminoethylene , not the carbene, reacted with the electrophile E X to generate ... plus the resultant salt. The free carbene could then either re dimerise regenerating the tetraaminoethylene ... of a Diaminocarbene Tetraaminoethylene Equilibrium . J. Am. Chem. Soc. , volume 121 issue 45, pages ... in 2000 that the Wanzlick equilibrium between a tetraaminoethylene and its corresponding carbene did ... more details
refimprove date April 2009 File Carboxylic acid dimers.png right thumb Dimers of carboxylic acid s are often found in vapour phase. A dimer is a chemical entity consisting of two structurally similar monomer s joined by bonds that can be either strong or weak, Covalent bond covalent or Intermolecular force intermolecular . The term homodimer is used when the two molecules are identical e.g. A A and heterodimer when they are not e.g. A B . The reverse of dimerisation is often called Dissociation chemistry dissociation . Noncovalent dimers Carboxylic acid s form dimers by hydrogen bonding of the acidic hydrogen and the carbonyl oxygen when anhydrous. For example, acetic acid forms a dimer in the gas phase, where the monomer units are held together by hydrogen bond s. Under special conditions, most OH containing molecules form dimers, e.g. the water dimer . Borane BH sub 3 sub occurs as the dimer diborane B sub 2 sub H sub 6 sub , due to the high Lewis acid ity of the boron center. Excimer s and exciplex es are Excited state excited structures with a short lifetime. For example, noble gas es do not form stable dimers, but do form the excimers Ar sub 2 sub , Kr sub 2 sub and Xe sub 2 sub under high pressure and electrical stimulation. Covalent dimers File Dicyclopentadiene structure.svg thumb right 100px The dimer of cyclopentadiene although this might not be readily apparent on initial inspection Molecular dimers are often formed by the reaction of two identical compounds e.g. 2A A A. In this example, monomer A is said to dimerise to give the dimer A A . An example is a diaminocarbene , which dimerise to give a tetraaminoethylene 2 C NR sub 2 sub sub 2 sub R sub 2 sub N sub 2 sub C C NR sub 2 sub sub 2 sub Carbene s are highly reactive and readily form bonds. Dicyclopentadiene is an asymmetrical dimer of two cyclopentadiene molecules that have reacted in a Diels Alder reaction to give the product. Upon heating, it cracks undergoes a retro Diels Alder reaction to give i ... more details
Encyclopedia
top
