|Melting point||125 to 129 °C (257 to 264 °F; 398 to 402 K)|
|Solubility in water||organic solvents|
|Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)|
|(what is: / ?)|
Salen is the abbreviation for a popular chelating ligand used in coordination chemistry and homogeneous catalysis. The name salen is a contraction for salicylaldehyde and ethylenediamine. The ligand is a bright yellow micaceous solid that is soluble in polar organic solvents.
The diphenol H2salen is the conjugate acid of the ligand that logically is salen2-. But the terminology is used loosely. As an anionic tetradendate ligand, salen2- resembles tetradentate ligands including those that are macrocyclic, such as porphyrinate, corrin, bis(dimethylglyoximate), and some Schiff bases.
SalenH2 is commercially available. It was first prepared by Pfeiffer. It is often generated in situ followed by the addition of the metal salt, but the ligand is also easily prepared as a pure organic compound by the condensation of ethylenediamine and salicylaldehyde.
- P. Pfeiffer, E. Breith, E. Lübbe, T. Tsumaki (1933). ""Tricyclische orthokondensierte Nebenvalenzringe". Justus Liebig's Annalen der Chemie 503: 84–130. doi:10.1002/jlac.19335030106.
- Harvey Diehl, Clifford C. Hach (1950). "Bis(N,N' - Disalicylalethylenediamine) -μ - Aquodicobalt(II)". Inorg. Synth. Inorganic Syntheses 3: 196–201. doi:10.1002/9780470132340.ch53. ISBN 978-0-470-13234-0.