Green Oxidation Catalysts Synthesis of a catalyst for environmentally benign oxidation by N 2 O Addie Summitt and Megumi Fujita* Department of Chemistry, University of West Georgia, Carrollton, GA Introduction Ni Complexation Acknowledgments GEMS Summer Research Program National Science Foundation STEP grant #DUE Amna Ali, a senior research student However, the complex resulted in internal oxidation, and was not catalytic. Previously Known N 2 O-Activating Complexes Involving Ni Hillhouse published a Ni complex that reacted with N 2 O and activated the O atom. Catalyst Design Nickel was selected as a central metal ion because of the previous example by Hillhouse that showed N 2 O activation by a Ni complex. The catalyst is made up of a bulky tridentate ligand around a metallic center, in this case a Ni center. It was proposed that activation of nitrous oxide requires two coordination sites next to each other. This ligand allows three available coordination sites, two of which may be used for N 2 O activation. Another advantage is the overall -2 ligand charge, which neutralizes the central metal ion. This will create an overall neutral metal complex which is compatible with organic reaction media. Ligand Synthesis Ligand in CD 3 CN (burnt orange) Overall reaction took about 3 days. Pure crystals were obtained from ethyl acetate as 1:1 co-crystals with the solvent, confirmed by elemental analysis. Ligand + 2NaH in CD 3 CN (brown) Ni Complexation in CD 3 CN (dark purple) 1 H NMRs Attempts for Crystallization Conclusion and Future Work After a solubility test in toluene, diethyl ether, and hexanes, a crystallization attempt of the Ni Complexation was done with toluene- hexanes two solvent method; toluene being the good solvent and hexanes being the poor solvent. Nitrous oxide is a very destructive greenhouse gas released by many industrial waste sites; however, in the presence of a well designed metal catalyst, this gas has the potential to be an oxidation reagent. This potential oxidation by N 2 O could be exploited in many industrial oxidation processes as an environmentally friendly alternative because the only byproduct of the oxidation would be an environmentally benign N 2 gas. The use of such a catalyst in industries would contribute to the reduction of N 2 O into the environment, which in turn would help reduce the destruction of the Earth’s ozone layer. Our research goal is to develop a transition metal catalyst to activate N 2 O and mediate in the oxygen atom transfer to an organic substrate. The synthesis reactions conducted thus far have been very successful. Future work includes having a successful reaction between the tridentate ligand and NiCl 2, and then testing the catalyst for catalytic behavior. Mechanism of N 2 O Activation The first step in the N 2 O activation is to have a ligand with a metal center (our catalyst) take the oxygen atom from the N 2 O. The catalyst then acts as the oxidizing agent as it transfers the oxygen to a gas like CH 4. A good catalyst would be able to repeat this cycle over and over again. * * (s) (s) : starting ligand * * **** (s) * : new species (Ni complex?) (u) : unknown impurity (u) No NH peak: deprotonation complete (u) NH The yield of each step has been improved by optimizing the reaction, workup, and purification conditions. This is the first time our lab produced this ligand in a large (2 g) scale, which allows us to explore metal complexation chemistry. † : tentatively assigned as Na salt of ligand †† † † † ††† (u)