Research Seminar
Catalytic generation of nitric oxide (NO) at material surfaces improves implanted medical device performance. Devices containing the metal-organic framework (MOF) [(Cu4Cl)3–(BTTri)8] (CuBTTri) catalyze NO release from the endogenous tripeptide S-Nitrosoglutathione (GSNO). MOFs are hybrid inorganic-organic materials that are promising heterogeneous catalysts due to their tunability, well-defined geometry, porosity, and high surface area. We have developed a method using 1H nuclear magnetic resonance (NMR) spectroscopy and a nitric oxide analyzer to quantitatively monitor all reactants and products for GSNO to NO conversion in real time directly in H2O. The GSNO to NO release reaction monitoring method yields the full reaction stoichiometry, CuBTTri catalyst dependence on added thiol, and location / number of catalytically active Cu sites in CuBTTri. Comparing CuBTTri particle size to the reaction rate reveals that GSNO to NO conversion catalysis is confined to CuBTTri particle exterior surfaces and that no intrapore Cu sites are catalytically active. Cyanide catalyst poisoning shows that catalysis is caused by a single type of Cu site. Based on infrared spectroscopic analysis of cyanide-poisoned CuBTTri, one active Cu site binds 3 equivalents of cyanide. Size-selective poisoning using 3,3′,3″-phosphanetriyltris trisodium salt was employed to count the catalytically active, exterior surface Cu sites and calculate a normalized catalyst turnover frequency.
Meeting ID:980 8740 7340
