Template synthesis and structure of mono- and trisubstituted ribbed-functionalized iron(II) clathrochelates

The template condensation of three methylchloroglyoximate molecules with phenylboronic acid and with BF3 · O(C2H5)2 on an iron(II) ion afforded reactive trichloride phenylboron- and fluoroboron-capped precursors, respectively. The monochloride FeBd2(CH3ClGm)(BF)2 precursor (where Bd2− and CH3ClGm2− are α-benzyldioxime and methylchloroglyoxime dianions) was synthesized by condensation of macrocyclic iron(II) α-benzyldioximate FeBd2(BF2)2(CH3CN)2 with CH3ClGmH2. Mono- and trifunctionalized amine, alkylsulfide, and arylsulfide clathrochelate iron(II) tris-dioximates were prepared starting from these precursors by nucleophilic substitution reactions. The complexes obtained were characterized using elemental analysis, PD mass, IR, UV–Vis, 1H, 13C NMR, and 57Fe Mössbauer spectra, and X-ray crystallography. An encapsulated low-spin iron(II) ion was found to have distorted trigonal-prismatic coordination N6-environment in all clathrochelates synthesized.