TAML Activators as Green Oxidation Catalysts: Kinetic and Mechanistic Studies, Applications in Pollutant Remediation and Organic Synthesis

Chapter 1 TAML activators are non-heme iron containing homogeneous catalysts which activates hydrogen peroxide in water under ambient conditions at rates comparable to that of peroxidase enzymes. This chapter includes an introduction to TAML activators, the chemistry of high-valent iron-oxo complexes, and a short review of the applications of TAML activators in pollutant remediation and in organic synthesis.;Chapter 2 Ferric tetraamido macrocyclic ligand based catalysts [Fe{C6H4-1,2-(NCOCMe2NCO)2CR 2}(OH2)]PPh4 (R = Me, ET) are oxidized by meta-chloroperoxybenzoic acid (mCPBA) at --40 °C in acetonitrile in two steps to form iron(V)oxo complexes. These uniquely authenticated FeV(O) species comproportionate with the Fe III starting materials to give mu-oxo-(FeIV) 2 dimers.;Chapter 3 Detection of highly reactive intermediates under fast turnover conditions in low reagent concentrations is incredibly difficult. Kinetic evidence for four FeIV TAML intermediates was obtained during the 1e oxidation of ferrocyanide by catalytic TAML activator/H2O2. The FeIV TAML intermediates are involved in fast acid-base equilibrium. The counterintuitive reactivity pattern is explained by the overall free energy change during the reduction of FeIV to FeIII TAML complexes, with competing contributions from electronic and solvation energy changes.;Chapter 4 The organophosphorus (OP) insecticide, chlorpyrifos (CP, O,O-diethyl-O-3,5,6-trichloro-2-pyridyl phosphorothioate) in an emulsifiable concentrate formulation (CP-EC) is totally degraded in water by hydrogen peroxide catalytically activated by a TAML activator, to a combination of small aliphatic acids and minerals. CP-EC rapidly forms an oil-in-water emulsion when added to water. The CP in this emulsion is more resistant to oxidation than pure CP in aqueous solution.;Chapter 5 2,4,6-trinitrophenol (TNP), one of the most oxidatively resistant phenols, was oxidatively degraded by TAML activator/H2O 2 at neutral pH under ambient conditions. The reaction achieved complete degradation of TNP and the final mixture consisted of formic acid, nitrate, nitrite, and some of the carbon in TNP was mineralized as CO and CO2 . This indicates deep oxidation of TNP by the prescribed method.;Chapter 6 This work deals with a green and efficient catalytic oxidation process to remove trinitroaromatics from water. The oxidative resistance of TNT and TNB can be overcome by forming Meisenheimer complexes in basic solution in the presence of a cationic surfactant, such as CTAB and CTAC. On treatment with TAML activator/ROOH (R= H, t-Bu), these complexes degrade into small aliphatic acids and minerals.;Chapter 7 This chapter demonstrates the fine tuning of the reactivity of TAML/H2O2 to make them effective in the selective functional group transformation in organic molecules. Catalytic TAML activators and H2O2 was used successfully for the mono nitration of phenols in presence of nitrite salts and chemoselective oxidation of organic sulfides to sulfoxides in water (close to neutral pH) and under ambient conditions. Nitrophenols and organic sulfoxides are important target molecules due to their wide applications in various industries. These fast reactions resulted in the formation of the desired products in high yields. (Abstract shortened by UMI.).