Dr. Craig M. Davis

Research Interests

     Previously our group synthesized and structurally characterized [Ni(TRIPHOX)Cl₂] (see figure). The [Ni(TRIPHOX)Cl₂] complex was designed to catalyze the oxidation of primary alcohols to aldehydes, but no evidence of catalytic activity was observed.

     Since the coordination chemistry of the TRIPHOX ligand has received scant attention, we plan to synthesize a series of first-row transition-metal complexes, [M(TRIPHOX)Cl₂] (M = Mn, Fe, Co, Ni, Cu). Our next step will be to study their physical properties. In particular, ligands with oxime functional groups are well known to stabilize high oxidation states, such as Cu(III) and Cu(IV). We will allow our oxime complexes to react with a known oxidizing agent (ammonium persulfate, bromine, or nitric acid) to hopefully achieve these unusual oxidation states.

     Successful oxidations will initially be noted by UV-vis spectroscopy, as the absorbance peaks of transition-metal complexes are known to shift to lower wavelengths as the charge on the metal center increases. Ultimately, successful oxidations will be confirmed by determining the number of unpaired electrons with a magnetic susceptibility balance; such measurements will also allow us to determine if TRIPHOX is a strong-field or weak-field ligand. For example, Ni(II) (d⁸) has only one possible electron configuration, so it will have two unpaired electrons. However, both Ni(III) (d⁷) and Ni(IV) (d⁶) can adopt low-spin or high-spin electron configurations. The low-spin and high-spin d⁷ complexes will have one and three unpaired electrons, respectively. By contrast, the high-spin d⁶ complex will have four electrons, while the low-spin d⁶ complex will be diamagnetic.

Expertise

Inorganic Chemistry, Coordination Compounds