5-Dehydro-m-xylylene

Chembox new
Name = 5-Dehydro-m-xylylene
ImageFile = DMX_line.png ImageName = 5-Dehydro-m-xylylene
IUPACName = 5-dehydro-1,3-quinodimethane
OtherNames = 5-dehydro-"m"-xylylene,
DMX
Section1 = Chembox Identifiers
CASNo = 681440-83-5
Section2 = Chembox Properties
Formula = C₈H_{7
MolarMass = 103.14 g/mol}

5-dehydro-"m"-xylylene (DMX) is an aromatic organic triradical and the first known organic molecule to violate Hund's Rule. [cite journal | author = L Slipchenko "et al." | title = 5-Dehydro-1,3-quinodimethane: A Hydrocarbon with an Open-Shell Doublet Ground State | journal = Angewandte Chemie International Edition | year = 2004 | volume = 43 | pages = 742 | doi = 10.1002/anie.200352990]

Its electronic ground state is an "open-shell doublet" rather than a quartet; that is, it contains three low-spin coupled unpaired electrons in three singly occupied molecular orbitals. Because there are radical electrons in both spin states, this compound is said to exhibit antiferromagnetism. Though similar ground states are observed in molecules containing transition metal atoms, it is unprecedented in organic molecules.

The 5-dehydro-"m"-xylylene anion (DMX^-) has also been studied extensively. It has a triplet ground state consisting of a phenyl anion and a "m"-xylylene biradical.

References

External links

* [http://physicsweb.org/articles/news/8/2/5 Physics web - Radical molecule breaks the rules]
* [http://www.chem.purdue.edu/NewsFeed/newsstory.asp?itemID=94 Purdue University Department of Chemistry - ‘Rule-breaking’ molecule]