A ligand strand that displays anion-dependant reactivity with acetonitrile; formation of either a mononuclear complex or head-to-tail circular helicate

Abstract

The ligand L^2,2 contains two bidentate domains separated by a 3,3-diamino-2,2′-biphenyl spacer unit and with Cu(ClO₄)₂ a mononuclear species is formed (e.g. [Cu(L^2,2)]²⁺). Upon coordination with Cu(triflate)₂ the ligand undergoes reaction with an acetonitrile solvent, producing a different ligand with unsymmetrical bidentate and tridentate domains (L^2,3). This new ligand results in the formation of a tetranuclear head-to-tail circular helicate [Cu₄(L^2,3)₄]⁸⁺ showing that in the presence of the triflate anion the ligand denticity is changed.