Synthesis of novel first-row transition metal-N-heterocyclic carbene complexes and synthesis of N-heterocyclic carbene-functionalized linkers for metal organic frameworks

Abstract

Although <i>N</i>-heterocyclic carbene ligands are highly versatile and powerful ligands in transition metal catalysis, complexes of <i>N</i>-heterocyclic carbenes with 3d metals are uncommon and frequently unstable. In order to explore the reactivity of some 3d metal-<i>N</i>-heterocyclic carbene complexes, two tridentate <i>NCN</i> pincer ligands were prepared: 1,3-bis(2- pyridylmethyl)imidazolium chloride and 1,3-bis(2-pyridylmethyl)benzimidazolium chloride. These ligands were coordinated to copper(II) and nickel(II) salts in air to yield a variety of 3d metal-<i>N</i>-heterocyclic carbene complexes. The counterion to the metal cation appears to have a significant influence on the coordination mode of the ligands and geometry around the metal centres. Synthesis of the novel metal complexes, as well as possible applications, are described herein.<br> Carbon dioxide is the primary contributor to climate change. As such, materials that can capture and fix carbon dioxide are important tools to limit climate change. One highly effective class of material for gas adsorption is metal-organic frameworks. In an effort to prepare a metal-organic framework with superior carbon dioxide capture and fixation capabilities, a series of linkers with <i>N</i>-heterocyclic carbene moieties were designed, of which two were successfully prepared. Thus far, efforts to prepare a metal-organic framework based on either of the two linkers have been unsuccessful.