There are two main areas of research being pursued at present: (i) coordination chemistry of new multidentate mixed-donor ancillary ligands, and (ii) activation and functionalization of molecular nitrogen.
Because the reactivity of a metal complex can be fine-tuned by the ligands that surround the metal, it becomes important to examine new kinds of ligands and ligand combinations. The tridentate ancillary ligand 1 (PNP) incorporates both the "hard" amide donor and the "soft" phosphine ligand to generate a unique environment capable of binding to most elements in the periodic table. We have recently expanded the scope of this ligand by preparing the macrocyclic version 2 (P2N2) and the related tridentate system 3 (NPN). These three ligand types are versatile because of the backbone flexibility and the variations possible in substituents. New variations of NPN involving o-phenylene linkers are currently in progress; for example, 4 (NPN*) has been prepared and its coordination chemistry is under investigation.
As all of this research involves the manipulation of air- and moisture-sensitive materials, researchers in this laboratory have access to state-of-the-art inert atmosphere workstations.
KEYWORDS : nitrogen fixation, ligand design, transition metal chemistry, lanthanides, homogeneous catalysis, polymerization.