Design Of First-Row Transition Metal Bis(alkoxide) Complexes And Their Reactivity Toward Nitrene And Carbene Transfer

DESIGN OF FIRST-ROW TRANSITION METAL BIS(ALKOXIDE) COMPLEXES AND THEIRREACTIVITY TOWARD NITRENE AND CARBENE TRANSFERbyJAMES A. BELLOWAugust 2016Advisor: Dr. Stanislav GroysmanMajor: Chemistry (Inorganic)Degree: Doctor of PhilosophyThe novel alkoxide ligand [OCtBu2Ph], or [OR], was synthesized in a single step as a lithium salt.It was then reacted with a series of first-row transition metal(II) halides, with widely varying results.Upon reaction with chromium, manganese, iron, or cobalt(II) chloride, dimeric complexes of the formM2(OR)4Li2Cl2 were formed, which displayed rare seesaw geometry at the metal. This unusual geometrywas confirmed by various spectroscopic and computational studies. Computational studies also indicate that the steric bulk of the ligand, as well as the inclusion of lithium atoms in the molecules, are what leadto the seesaw geometry. Reaction of [OR] with nickel(II) halides generates monomeric species of theform Ni(OR)2XLi(THF)2 (X = Cl, Br), which display distorted trigonal planar geometry at three-coordinate nickel. Dimerization likely does not occur for nickel due to its smaller size. DFT studiessupport preference for nickel to form the monomer. Reaction of [OR] with copper(II) halides leads toreduction of the copper center by one electron, generating the tetramer Cu4(OR)4. Reduction of copper(II)by an alkoxide is a novel transformation. Spectroscopic studies to probe the mechanism suggest thatCu(OR)2XLi(THF)2 may be an intermediate prior to reduction. Observation by NMR of the ketonePh(C=O)tBu and ROH suggest that alkoxide reduces the copper to give an alkoxide radical, which thendecomposes via β-scission.To form the desired bis(alkoxide) system, the halide-containing alkoxide complexes were reactedwith thallium(I) hexafluorophosphate. For manganese, iron, and copper, complexes of the form