Synthesis, structural characterization, and properties of a new range of strained 2-aza[3]ferrocenophane ligands: Dual behavior as electrochemical sensors of metal ions or anions

摘要

The synthesis of structurally new types of strained 2-aza[3]ferrocenophanes, 9 and 10, which comprise a benzoquinuclidine framework incorporating a 1,1'-disubstituted ferrocene unit is reported. These compounds were prepared in four steps from the readily available 1,1'-diacetylferrocene and thoroughly characterized by spectroscopic means and electrochemical methods. The ligands 9 and 10 act as electrochemical sensors either of Mg2+, Zn2+, and Ni2+ cations (free ligands), where a new redox peak appears in the CV shifted 310-350 mV, or hydrogensulfate anion (protonated ligand) via a significant cathodic perturbation. The crystal structures of compounds 9 and 9b (9.HClO4) have been determined by single-crystal X-ray methods. In the latter compound the anion and cation are associated onto ribbons parallel to the z axis by four hydrogen bonds. [References: 50]