Template synthesis and structures of bis-ferrocenylboronate macrobicyclic iron(II)tris-dioximates

摘要

A series of ferrocenylboron-capped tris-dioximate iron(II) clathrochelates was synthesized by the template condensation of three molecules of dimethylglyoxime (H2Dm), cyclohexanedione 1,2-dioxime (H2Nx), orcyclooctanedione 1,2-dioxime (H2Ox) and two molecules of ferrocenylbo-ronic acid (FcB(OH)2) on the Fe~(2+) ion matrix. The yields of the clathrochelate derivatives of alicyclic dioximes were substantially higher than that of their acyclic analog, because the molecules of alicyclic H2Nx and H2Ox a-dioximes have the s-cis-configuration suitable for complex formation, whereas the H2Dm molecules in solution have the s-trans-configuration. The synthesized compounds were characterized using elemental analysis, IR and UV-Vis spectroscopies, MALDI-TOF mass spectrometry, ~1H and ~(13)C{~1H} NMR and ~(57_Fe Mossbauer spectroscopies, and X-ray diffraction analysis. The crystal of FeDm3(BFc)2 · CHCl3 contains two types of crystallographically nonequivalent clathrochelate molecules. The intermolecular contacts C-H...Cp formed by the ferrocenyl fragments and cyclooctane carbocycles and the interactions Cp-H.. .O were observed in the crystal of FeOx3(BFc)2. The structural lability of the cyclooctane substituents allows the FeOx3(BFc)2 molecules to arrange by the "bump-into-hollow" mode because of attractive H...H interactions between the ribbed substituents of the neighboring molecules. The geometry of the ferrocenylborate iron(II) clathrochelates is intermediate between a trigonal prism and a trigonal antiprism.