UC Riverside

Transition metal catalysis is dominated by two electron transformations, often mediated by costly noble metals. In this research, we have explored an alternate approach, using inexpensive iron complexes in weak ligand fields. Through ligand design, we have isolated unprecedented low-valent, high-spin coordination complexes of a range of unsaturated ligands including arenes, alkenes, and alkynes. In one case, we report the first high-spin η2-arene metal complexes and their properties. While the arene is bound weakly, spin density is conferred to it upon binding. We also describe a novel C−H activation mechanism whereby bulky phenoxyl radicals can abstract a hydrogen atom directly from the coordinated alkene or alkyne. This enabled the activation of sp3, sp2, and sp C−H bonds in 2-butyne, ethylene, and phenylacetylene. In an unrelated project, we have investigated the chemistry of highly reduced transition metal complexes stabilized by diboraanthracene ligands, and describe the isolation and characterization of the first molecular platinide complex.