Salen ligand
| Salen ligand | ||
|---|---|---|
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| Other names 2,2'-Ethylenebis(nitrilomethylidene)diphenol, N,N'-Ethylenebis(salicylimine) | ||
| Identifiers | ||
| CAS number | 94-93-9  | |
| Properties | ||
| Molecular formula | C16H16N2O2 | |
| Molar mass | 268.31 | |
| Appearance | yellow solid | |
| Melting point | 125 to 129 °C; 257 to 264 °F; 398 to 402 K | |
| Solubility in water | organic solvents | |
(verify) (what is: / ?)Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa) | ||
| Infobox references | ||
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.
Nomenclature
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.
Preparation
SalenH2 is commercially available. It was first prepared by Pfeiffer.[1] 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.[2]
References
- ↑ 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.