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Full-Text Articles in Physical Sciences and Mathematics

Origin Of Enantioselection In Chiral Alcohol Oxidation Catalyzed By Pd[(–)-Sparteine]Cl2, J. A. Mueller, Anne Cowell, Bert D. Chandler, M. S. Sigman Sep 2005

Origin Of Enantioselection In Chiral Alcohol Oxidation Catalyzed By Pd[(–)-Sparteine]Cl2, J. A. Mueller, Anne Cowell, Bert D. Chandler, M. S. Sigman

Chemistry Faculty Research

A kinetic investigation into the origin of enantioselectivity for the Pd[(–)-sparteine]Cl2-catalyzed aerobic oxidative kinetic resolution (OKR) is reported. A mechanism to account for a newly discovered chloride dissociation from Pd[(–)-sparteine]Cl2 prior to alcohol binding is proposed. The mechanism includes (1) chloride dissociation from Pd[(–)-sparteine]Cl2 to form cationic Pd(–)-sparteine]Cl, (2) alcohol binding, (3) deprotonation of Pd-bound alcohol to form a Pd-alkoxide, and (4) β-hydride elimination of Pd–alkoxide to form ketone product and a Pd–hydride. Utilizing the addition of (–)-sparteine HCl to control the [Cl] and [H+] and the resulting derived rate law, …


Low-Temperature Activation Conditions For Pamam Dendrimer Templated Pt Nanoparticles, Anil Singh, Bert D. Chandler Aug 2005

Low-Temperature Activation Conditions For Pamam Dendrimer Templated Pt Nanoparticles, Anil Singh, Bert D. Chandler

Chemistry Faculty Research

Surface immobilized polyamidoamine (PAMAM) dendrimer templated Pt nanoparticles were employed as precursors to heterogeneous catalysts. CO oxidation catalysis and in situ infrared spectroscopy were used to evaluate conditions for dendrimer removal. Infrared spectroscopy showed thatPAMAMdendrimer amide bonds begin decomposing at temperatures as low as 75 °C. Although the amide stretches are completely removed after 3 h of oxidation at 300 °C, 16 h were required to reach maximum catalytic activity. Further treatment under oxidizing or reducing atmospheres did not cause substantial changes in activity. Infrared spectroscopy of the activated materials indicated that organic residues, probably surface carboxylates, are formed during …


Fast Oxidation Of Lactams To Cyclic Imides Using Microwave Irradiation, Avat Arman Taherpour, Hamid Reza Mansuri Jan 2005

Fast Oxidation Of Lactams To Cyclic Imides Using Microwave Irradiation, Avat Arman Taherpour, Hamid Reza Mansuri

Turkish Journal of Chemistry

Since polar reactants can adsorb microwave irradiation, chemists can utilize the microwave oven for some organic reactions. In this paper, we report a rapid conversion of lactams to cyclic imides using peracetic acid (CH_3-CO_3H) and manganic chloride (MnCl_2) in ethyl acetate (CH_3-COOEt) as a solvent and under microwave irradiation (90 W, 5 min) in good yields.