Template Synthesis of the Iron(III) Complex with the Ligands Based on Acylpyrazolonepyridines

The reaction of new bidentate ligand, 1-(5-hydroxy-1-methyl-3-(pyridin-2-yl)-1Н-pyrazol-4-yl)ethan-1-one (L), with iron(III) chloride affords the mononuclear iron(III) complex FeL₂Cl₃, which is characterized by XRD (CIF file CCDC no. 2309481). The intramolecular hydrogen bond between the protonated pyridyl and acetyl groups in ligand L, which exists in the crystal as a zwitterion, provides the formation of rarely met iron complexes in which the β-diketonate fragment coordinates via the η¹ mode. A similar coordination mode along with a possibility of a more favorable η² coordination provides new possibilities for the design of heteropolynuclear compounds of various structures used in the fabrication of molecular devices of data storage and processing.