Template synthesis, structure and spectra of the semiclathrochelate and clathrochelate 1,4-pentadienylboron-capped iron(II) oximehydrazonates

Abstract The direct template condensation of diacetylmonooxime hydrazone with the 1,4-pentadienylboronates as Lewis acids on an iron(II) ion matrix led to the 1,4-pentadienylboron-capped semiclathrochelate iron(II) oximehydrazonates. The H + -ion-catalyzed macrocyclization of these precursors with an excess of triethyl orthoformate resulted in macrobicyclic complexes with a single apical 1,4-pentadienyl substituent. The complexes obtained were characterized using elemental analysis, MALDI-TOF mass spectrometry, IR, UV–Vis, 1 H, 11 B{ 1 H} and 13 C{ 1 H} NMR, 57 Fe Mossbauer spectroscopies, and X-ray crystallography. The X-ray diffraction and NMR data for complexes obtained showed the syn , syn , syn -orientation of all ethoxy substituents in 1,3,5-triazacyclohexane capping fragment in relation to a clathrochelate framework.