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Bimetallic nanoparticles containing Au and Pd were synthesized using poly(vinylpyrrolidone) (PVP) as the polymer stabilizer using both co-reduction and sequential reduction strategies. The nanoparticle structures and catalytic activities for the aerobic oxidation of crotyl alcohol to crotonaldehyde at room temperature in the absence of base were investigated. The chemical, structural, and electronic properties of these nanoparticles were investigated using Pd-K-edge and Au-LIII-edge extended X-ray absorption fine structure (EXAFS) spectroscopy and Pd-LIII and Au-LIII edge X-ray absorption near edge structure (XANES) spectroscopy. EXAFS analysis for the sequentially reduced bimetallic systems indicates the presence of significantly Pd-enriched surfaces and Au cores. XANES spectra of the Pd-LIII edges indicated that the sequentially reduced particles showed significant d-charge depletion compared to pure monometallic Pd and co-reduced AuPd nanoparticles. The sequentially reduced nanoparticles with Pd rich surfaces were extremely active for crotyl alcohol oxidation at room temperature in the absence of base, and were quite selective for the formation of crotonaldehyde. A proposed mechanism for the reaction involving the oxidation and re-reduction of Pd on the surface of the particles is postulated based on catalytic activity measurements using sequentially reduced particles and control reactions with Pd2+ salts in the absence and presence of Au, Pd, and Pt nanoparticles.

A series of poly(vinylpyrrolidone) (PVP)-stabilized metallic and bimetallic PdAu nanoparticles (coreduced and core-shell) with narrow size distributions were encapsulated into alumina matrixes by sol-gel chemistry, and their chemical, structural, electronic, and catalytic behaviors were investigated. Monodisperse nanoparticles were uniformly distributed in the alumina frameworks as observed by TEM images, and single-particle energydispersive spectroscopy (EDS) analyses confirmed the high compositional uniformity of the bimetallic nanoparticles. A combination of TEM, EDS mapping, TGA, XANES and EXAFS studies were used to fully characterize the alumina-supported nanoparticles before and after thermal treatments. It was observed that the size distribution of the final PdAu nanoparticles was highly dependent on calcination conditions, and careful high-temperature calcinations at 300 °C could be used to remove organic PVP stabilizers with minimal particle aggregation and/or structural transformations. The resulting supported nanoparticle catalysts were found to be active as hydrogenation catalysts. EXAFS analysis of coreduced PdAu nanoparticles indicated they had near-alloy structures with slightly Au-rich cores and Pd-rich shells before and after calcination, while intentionally designed Pd-core Au-shell nanoparticles retained their structures after calcination. XANES spectra of both coreduced and core-shell PdAu nanoparticles were also examined and showed that the PdAu coreduced nanoparticles had fewer Au valence d-band vacancies in comparison to monometallic nanoparticles while the PdAu core-shell nanoparticles had relatively higher Au valence d-band vacancies than the coreduced PdAu nanoparticles.

The switchability and bicarbonate formation of CO2 triggered aryl amidine and tertiary amine switchable surfactants have been investigated. Despite the lower basicity of these compounds compared to alkylacetamidine switchable surfactants, it was found that amidinium and ammonium bicarbonates could be formed in sufficiently high enough concentrations to perform emulsion polymerization of methyl methacrylate and stabilize the resulting colloidal latexes. Particle sizes ranging from 80 to 470 nm were obtained, and the effects of surfactant concentration, surfactant basicity, initiator type, initiator concentration, and CO2 pressure on particle size and ζ-potential have been examined. Destabilization of latexes is traditionally achieved by addition of salts, strong acids for anionically stabilized latexes, or alkalis for cationically stabilized latexes. However, with CO2-triggered switchable surfactants, only air and heat are required to destabilize the latex by removing CO2 from the system and switching the active amidinium or ammonium bicarbonate surfactant to a surface inactive neutral compound. This process occurs much more rapidly in the case of these less basic aryl amidine and tertiary amine based surfactants compared to previously reported alkyl amidine surfactants.

Catalytic cross-coupling of aryl Grignard reagents with primary and secondary alkyl halides bearing beta-hydrogens is achieved using Fe(III) amine-bis(phenolate) halide complexes.

The structures and properties of six new iron(iii) diamine-bis(phenolate) complexes are reported. Reaction of anhydrous FeX(3) salts (where X = Cl or Br) with the diprotonated tripodal tetradentate ligands 2-pyridylamino-N,N-bis(2-methylene-4-methyl-6-tert-butylphenol), H(2)[L(1)], and N,N-dimethyl-N',N'-bis(2-methylene-4-methyl-6-tert-butylphenol)ethylenediamine, H(2)[L(2)], produces the trigonal bipyramidal iron(iii) complexes, [L(1)]FeCl , [L(1)]FeBr , [L(2)]FeCl and [L(2)]FeBr . Reaction of FeX(3) with the related linear tetradentate ligand N,N'-bis(4,6-tert-butyl-2-methylphenol)-N,N'-bismethyl-1,2-diaminoethane, H(2)[L(3)], generates square pyramidal iron(iii) complexes, [L(3)]FeCl and [L(3)]FeBr . Complexes have been characterized using electronic absorption spectroscopy and magnetometry. Single crystal X-ray molecular structures have been determined for complexes 1, 3, 5 and 6.

A series of cobalt(II) amine-bis(phenolate) complexes has been prepared and characterized. The protonated tripodal tetradentate ligand precursors; dimethylaminoethylamino-N,N-bis(2-methylene-4-tert-butyl-6-methylphenol),

Eight new iron(III) amine-bis(phenolate) complexes are reported. The reaction of anhydrous FeX(3) salts (where X = Cl or Br) with the diprotonated tripodal tetradentate ligands 2-tetrahydrofurfurylamino-N,N-bis(2-methylene-4,6-di-tert-butylphenol), H(2)L1, 2-tetrahydrofurfurylamino-N,N-bis(2-methylene-4-methyl-6-tert-butylphenol), H(2)L2, and 2-methoxyethylamino-N,N-bis(2-methylene-4,6-di-tert-butylphenol), H(2)L3, 2-methoxyethylamino-N,N-bis(2-methylene-4-methyl-6-tert-butylphenol), H(2)L4 produces the trigonal bipyramidal iron(III) complexes, L1FeCl (1a), L1FeBr (1b), L2FeCl (2a), L2FeBr (2b), L3FeCl (3a), L3FeBr (3b), L4FeCl (4a), and L4FeBr (4b). All complexes have been characterized using electronic absorption spectroscopy, cyclic voltammetry and room temperature magnetic measurements. Variable temperature magnetic data were acquired for complexes 2b, 3a and 4b. Variable temperature Mössbauer spectra were obtained for 2b, 3a and 4b. Single crystal X-ray molecular structures have been determined for proligand H(2)L4 and complexes 1b, 2b, and 4b.