In organic chemistry, a Bechgaard salt is any one of a number of organic

charge-transfer complex In chemistry, a charge-transfer (CT) complex or electron-donor-acceptor complex describes a type of supramolecular assembly of two or more molecules or ions. The assembly consists of two molecules that self-attract through electrostatic forces ...

es that exhibit

superconductivity Superconductivity is a set of physical properties observed in certain materials where electrical resistance vanishes and magnetic flux fields are expelled from the material. Any material exhibiting these properties is a superconductor. Unlike ...

at low temperatures. They are named for chemist

Klaus Bechgaard Klaus Bechgaard (5 March 1945 – 7 March 2017) was a Danish scientist and chemist, noted for being one of the first scientists in the world to synthesize a number of organic charge transfer complexes and demonstrate their superconductivity, ther ...

, who was one of the first scientists to synthesize them and demonstrate their superconductivity with the help of physicist

Denis Jérome Denis Jerome (born 28 February 1939 in Paris) is a French experimental physicist in the field of condensed matter, who contributed to the discovery of superconductivity in organic conductive matter. Career He studied at the Sorbonne, where he o ...

. Most Bechgaard salt superconductors are extremely low temperature, and lose superconductivity above the 1–2 K range, although the most successful compound in this class superconducts up to almost 12 K. All Bechgaard salts are formed using a small, planar organic molecule as an electron donor, with any of a number of

electron acceptor An electron acceptor is a chemical entity that accepts electrons transferred to it from another compound. It is an oxidizing agent that, by virtue of its accepting electrons, is itself reduced in the process. Electron acceptors are sometimes mista ...

s (such as perchlorate, , or tetracyanoethylene, TCNE). All the organic electron donors contain multiply conjugated heterocycles with a number of properties, including planarity, low ionization potential and good orbital overlap between heteroatoms in neighboring donor molecules. These properties help the final salt conduct electrons by shuttling them through the orbital vacancies left in the donor molecules. All Bechgaard salts have a variation on a single tetrathiafulvalene motif—different superconductors have been made with appendages to the motif, or using a tetraselena fulvalene center instead (which is a related compound), but all bear this general structural similarity. There are a wide range of other organic superconductors including many other charge-transfer complexes.

References

{{DEFAULTSORT:Bechgaard Salt Superconductivity Organic compounds

See also

References