Сален лигандтары: құрамы, қасиеттері және қолданылуы

Salen
Salen refers to a tetradentate C2 symmetric ligand synthesized from salicylaldehyde (sal) and ethylenediamine (en). It may also refer to a class of compounds, which are structurally related to the classical salen ligand, primarily bis Schiff bases. Salen ligands are notable for coordinating a wide range of different metals, which they can often stabilise in various oxidation states. For this reason salen type compounds are used as metal deactivators. Metal salen complexes also find use as catalysts.

[[File:JaegerMac. svg|thumb|280px|left|Synthesis and complexation of Jäger's ligand. Cobalt complexes [Co(acacen)L2]+, selectively inhibit the activities of histidine containing proteins through exchange of the axial ligands. These compounds show promise for the inhibition of oncogenesis. The salan and salalen ligands are similar in structure to salen ligands, but have one or two saturated nitrogen aryl bonds (amines rather than imines). They tend to be less rigid and more electron rich at the metal center than the corresponding salen complexes. Salans can be synthesized by the alkylation of an appropriate amine with a phenolic alkyl halide. The “half salen” ligands have only one salicylimine group. They are prepared from a salicylaldehyde and a monoamine. The name “salen” or “salen type” may be used for other ligands that have similar environment around the chelating site, namely two acidic hydroxyls and two Schiff base (aryl imine) groups. These include the ligands abbreviated as salph, from the condensation of 1,2 phenylenediamine and salicylaldehyde, and salqu, from the condensation of salicylaldehyde and 2 quinoxalinol.