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The A-cluster active site in acetyl coA synthase exploits a Ni(CGC)2- metallopeptide as a bidentate ligand to chelate the catalytically active square-planar nickel center used to produce acetyl coA. As Nature utilizes polypeptides to isolate and stabilize the active sites, we have set out to immobilize biomimetic complexes to polyethylene-glycol (PEG) rich polystyrene polymer beads (TentaGel). The PEG rich resin-beads serve to imitate the peptidic superstructure of enzyme active sites as well as to protect the resin-bound models from O2 decomposition. As a model of the NiN2S2 ligand observed in the A-cluster of acetyl coA synthase, the CGC tripeptide was constructed on resins using Merrifield solid phase peptide synthesis and then metallated with NiII to produce bright orange beads. Derivatization with M(CO)x (M = Rh, W) provided qualitative identification of Ο-Ni(CGC)M(CO)x n- via ATR-FTIR. Additionally, Neutron Activation Analysis (NAA) and UV-vis studies have determined the concentration of Ni and CGC, and qualitatively identify Ο-Ni(CGC)2-. Furthermore, infrared studies and NAA experiments have been used to identify and quantify Ο- Ni(CGC)Rh(CO)2 1-. The S-based reactivity of Ni(ema)2-, a good model of Ni(CGC)2-, toward oxygenation and alkylation has been pursued and compared to neutral NiN2S2 complexes. The spectroscopic, electrochemical and structural effects of these modifications will be discussed and supported using DFT computations and electrostatic potential maps of the resulting Ni(ema)*O2 2- and Ni(ema)*(CH2)3 complexes. Having firmly established the synthesis, characterization and reactivity of NiN2S2 2- systems in solution and resin-bound, CuIIN2S2 analogues were explored. The synthesis and identification of solution complexes, Cu(ema)2-, Cu(emi)2-, and Cu(CGC)2- via UV-Vis, EPR, and –ESI-MS will be discussed in addition to their S-based reactivity with Rh(CO)2 + . Furthermore, the resin-bound Cu(CGC)2- complex has been produced and characterized by EPR and its Rh(CO)2 adduct identified by ATR-FTIR and compared to the analogous NiN2S2 2- systems. As the active site of [FeFe] Hydrogenase utilizes a unique peptide-bound propane dithiolate bridge to support the FeFe organometallic unit, [FeFe]Hydrogenase models have been covalently anchored to the resin-beads via similar carboxylic acid functionalities. The characterization (ATR-FTIR, EPR, Neutron Activation Analysis), stability and reactivity of the immobilized models complexes are discussed as well as work toward establishing the microenvironment of resin-bound complexes.

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In this study, Mg-Cu thin film metallic thin films were fabricated via two ways, the co-deposition and post-annealing of the multilayered thin films. Amorphous Mg1-xCux, where x is from 38 to 82, thin films with nanocrystalline particles are able to be fabricated via co-sputtering. The mechanism of formation is different from the rapid quenching process. For the Mg-Cu co-sputtering system, the mechanical properties of the Mg-Cu co-sputtered films were tested via MTS nanoindenter. Mg23.5Cu76.5 exhibits a higher Young¡¦s modulus than Mg17.7Cu82.3 and Mg40.4Cu59.6 due to the partial amorphous structure. Moreover, the pop-in effects with a smaller size occurs of the Mg23.5Cu76.5 sample in a higher frequency than of the Mg17.7Cu82.3 and Mg40.4Cu59.6 samples. The small pop-in effects in the Mg23.5Cu76.5 sample approximate match the width of amorphous matrix via the HRTEM observation. Another process to form the amorphous thin film is via the post isothermal annealing process of the multilayered thin films. However, for the specimens of 20T32 consisting of 150-nm Mg and 50-nm Cu individual layers, the Mg individual layers would react to the Cu individual layers during the annealing at a temperature of 413 K owning to the slight negative heat of mixing. Due to the localized diffusion near the interfaces, Mg2Cu gradually form during the isothermal annealing since Mg2Cu is the most stable phase below 548 K [62]. Localized interdiffusion near the interfaces between Mg and Cu individual layers induced the formation of Mg2Cu rapidly. For the 40T32 specimens consisting of 15 nm Mg and 5 nm Cu individual layers, Mg2Cu rapidly form at 413 K due to the high interface energy. Then, the similar result exhibits in the 20T14 and 40T14 specimens annealed at 363 K.

Abstract Aluminum oxide was utilized as a carrier of active metals copper and manganese. Catalysts with various metal ratios and weight loadings were produced by incipient impregnation to treattoluene. From the 24 catalysts we prepared, this investigation selected the most effective catalyst, based on the conversion rate of toluene and CO2 yield. The influence of operating parameters of toluene oxidization on the conversion rate and long-term variations in catalytic activity were investigated, and the physical properties of catalysts were determined by SEM and XRD. The conversion rate for toluene and CO2 yield reached 95% when the Cu/Mn catalyst was used with a metal ratio of 1:1 and 20% loading at 350¢XC, an influent toluene concentration of 1000ppm, oxygen concentration of 21%, a space velocity of 12000 hr-1, and relative humidity of 26%. The toluene conversion rate increased as reaction temperature and influent concentration of oxygen increased, but decreased as the initial toluene concentration and space velocity increased. The long-term test proceeded for seven days at a constant influent toluene concentration of 1000ppm, constant oxygen concentration of 21%, constant space velocity of 12000hr-1 and constant relative humidity of 26%. The stability of the Cu/Mn catalyst structure was assessed. Differences between fresh and aged catalysts were analyzed using analytical instruments such as SEM, and XRD. No obvious deactivation of the catalytic surface was detected. Keywords aluminum oxide, Cu/Mn catalyst, toluene, and operational parameters

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We investigated the reactivity of difluorovinylidene groups (C2F2) on Cu(111) under ultrahigh vacuum conditions. Difluorovinylidene moieties bonded to surface were generated by the dissociative adsorption of 1,1-dibromodifluoroethylene. Temperature Programmed desorption (TPD) and reflection-adsorption infrared spectroscopy (RAIRS) revealed the thermal reaction pathways, and a variety of intermediates were identified or inferred. The major desorption product, hexafluoro-2-butyne (C4F6), was detected at 445 K. It invokes a step of fluoride addition to difluorovinylidene to render the intermediacy of C2F3. However, differences exist when the vibration data from F + C=CF2 were compared with those from C−CF3 and CF=CF2 in previous literature, implying that the form is neither ethylidyne nor vinyl. Based on the concept of fluorine hyperconjugation, density function theory (DFT) calculations were utilized to obtain two transition states, quasi-vinyl and -ethylidyne, which can account for the differences present in the IR spectra. The relative thermal stability follows the trend of vinyl > quasi-ethylidyne > quasi-vinyl > vinylidene > ethylidyne suggested by IR and DFT calculations. Finally, the end product, CF3C¡ÝCCF3, might be formed by coupling of two quasi-ethylidyne species via the partial allenic forms.