CO_2 Fixation by Copper(Ⅱ) Complexes of a Terpyridinophane Aza Receptor

摘要

Very often, biological processes are assisted by amino groups that fix or react with a given compound. A paramount example of such chemistry comes from the enzyme rubisco, which participates in the fixation of CO_2 by green plants through the formation of a carbamate moiety by reaction of CO_2 and a lysine assisted by Mg~(2+) or Mn~(2+) ions. The elusive carbamate moiety is further stabilized by formation of a hydrogen-bond network with other amino acid residues. In past years, some of us have concentrated on the study of the coordination chemistry of [1+1] aza cyclophane molecules containing different aromatic spacers and donor atoms. The goal was to generate coordinatiyely unsaturated metal sites, which could bind different substrates through the formation of ternary complexes occupying the vacant positions in the coordination sphere or by removing the labile ancillary ligands that would be completing the coordination spheres of the metal ions.