Toward the Synthesis of Trianionic Cerberus-Type N-Heterocyclic Carbenes and their Zwitterionic Gold and Silver Complexes
Date of Award
Master of Science in Chemical Sciences (MSCB)
Dr. Daniela Tapu
Dr. Michael Stollenz
Dr. Mark Mitchell
While early efforts have been made to explore the chemistry of neutral multitopic nonchelating N-heterocyclic carbenes (NHCs), limited progress has been made in the development of their anionic counterparts. This thesis describes the synthesis and characterization of a novel anionic tris(maloNHC) and its corresponding transition metal complexes. The free carbene was generated in situ by deprotonation of the corresponding zwitterionic salt with KHMDS. The free carbene was characterized by 1H and 13C NMR spectroscopy. The corresponding thione was obtained by addition of excess sulfur to the in situ generated carbene. The utility of the new carbene as ligand in organometallic chemistry has been proven by its incorporation into two new zwitterionic complexes of type [(MPPh)3(NHC)] (M = Au or Ag). These complexes have been characterized by 1H NMR and X-ray crystallography. With their unique topological properties, these systems have the potential to serve as building blocks for the preparation of novel metalorganic frameworks such as supramolecular cages and organometallic polymers, systems not accessible with the current arsenal of neutral Cerberus-type trisNHCs. Further studies aimed at the construction of such supramolecular systems are under way in our laboratory.
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