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.