Ligand-mediated formation of Cu/metal oxide hybrid nanocrystals with tunable number of interfaces

Combining domains of different chemical nature within the same hybrid material through the formation of heterojunctions provides the opportunity to exploit the properties of each individual component within the same nano-object; furthermore, new synergistic properties will often arise as a result of unique interface interactions. However, synthetic strategies enabling precise control over the final architecture of multicomponent objects still remain scarce for certain classes of materials. Herein, we report on the formation of Cu/MO_x (M = Ce, Zn and Zr) hybrid nanocrystals with a tunable number of interfaces between the two domains. We demonstrate that the organic ligands employed during the synthesis play a key role in regulating the final configuration. Finally, we show that the synthesized nanocrystals serve as materials platforms to investigate the impact of the Cu/metal oxide interfaces in applications by focusing on the electrochemical CO₂ reduction reaction as one representative example.

We report on the formation of Cu/metal oxide hybrid nanocrystals with a tunable number of interfaces between the two domains. We demonstrate that the organic ligands employed during the synthesis play a key role in regulating the final configuration.     

Efficient synthesis of highly substituted thiophenes from acetylenic esters, ethyl bromopyruvate, and tetramethylthiourea

The reaction of acetylenic esters with ethyl bromopyruvate in the presence of tetramethylthiourea led to highly functionalized thiophenes in excellent yields.     

Efficient Synthesis of Functionalized Thiazoles from Acid Chlorides,Tetramethylthiourea, Ethyl Bromopyruvate,and Ammonium Thiocyanate

An efficient synthesis of ethyl 2‐(dimethylamino)‐1,3‐thiazole‐4‐carboxylates is described via a four‐component reaction between acid chlorides, tetramethylthiourea, ethyl bromopyruvate, and ammonium thiocyanate.     

A Convenient Synthesis of Functionalized Indenopyrazolones from Indan‐1,2,3‐trione,Benzaldehydes, and Phenylhydrazine

A synthesis of cis‐3‐aryl‐3a,8b‐dihydro‐3a,8b‐dihydroxy‐1‐phenylindeno[1,2‐c]pyrazol‐4(1H)‐ones in good yields from the sequential reaction between benzaldehydes, phenylhydrazine, and indan‐1,2,3‐trione in MeCN is described (Scheme 1).     

Binding Effect of Common Ions to Human Serum Albumin in the Presence of Norfloxacin: Investigation with Spectroscopic and Zeta Potential Approaches

In this work, the toxic influence of metallic ions (Al³⁺, Cu²⁺, Mg²⁺, Pb²⁺) on human serum albumin (HSA) in the absence and presence of norfloxacin (NRF) was studied by spectroscopic approaches [fluorescence quenching, synchronous fluorescence, three-dimensional fluorescence, circular dichroism, resonance light scattering (RLS) and zeta potential techniques] under simulated physiological conditions. Fluorescence spectroscopy revealed that these metallic ions and NRF can quench the HSA fluorescence, and this quenching effect became more significant when both ion and drug are present together. The binding constants and binding sites of metal ions with HSA in the absence and presence of NRF were determined, based on the fluorescence quenching results. Ion aggregation gives rise to an enhancement of the RLS intensity for HSA and the critical induced aggregation concentration (C _CIAC) of the ions, causing HSA aggregation for binary and ternary systems. The zeta potential measurements indicate a combination of electrostatic and hydrophobic interactions between ion, NRF and HSA and the formed micelle-like clusters. These data illustrated that NRF has an effect on the interaction between HSA and metal ions, with relevance for various toxicological and therapeutic processes.     

Synthesis and kinetics of graft polymerization of methyl methacrylate from the RAFT coordinated surface of nano‐TiO2

Polymer chains of PMMA were grown from nano titania (n‐TiO₂) by the reversible addition‐fragmentation chain transfer polymerization process. The mechanism and kinetics of MMA polymerization from both solution and “grafted from” n‐TiO₂ were studied. The RAFT agent, 4‐cyano‐4‐(dodecylsulfanylthiocarbonyl) sulfanyl pentanoic acid, with an available carboxyl group was used to anchor onto the n‐TiO₂ surface, with the S?C(SC₁₂H₂₅) moiety used for subsequent RAFT polymerization of MMA to form n‐TiO₂/PMMA nanocomposites. The functionalization of n‐TiO₂ was determined by FTIR, XPS, partitioning studies, and thermal analysis. The livingness of the polymerization was verified using NMR and GPC, while the dispersion of the inorganic filler in the polymer was studied using electron microscopy, FTIR, and thermal analysis. The monomer conversion and molecular weight kinetics were explored for the living RAFT polymerization, both in solution and grafted from n‐TiO₂, with first‐order kinetics being observed in both cases. Increased graft density on n‐TiO₂ led to a lower rate of polymerization. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3926–3937, 2008     

1,1,3,3‐N,N,N′,N′‐Tetramethylguanidinium Trifluoroacetate Ionic Liquid–Promoted Efficient One‐Pot Synthesis of Trisubstituted Imidazoles

Trisubstituted imidazoles have been synthesized in very short reaction times with excellent yields in the presence of 1,1,3,3‐N,N,N′,N′‐tetramethylguanidinium trifluoroacetate as an ionic liquid at 100°C. The ionic liquid can be recycled for subsequent reactions without any appreciable loss of efficiency.     

Application of Restrictive Primitive SAFT Coupled with Different Hard-Sphere Equations to Model Mean Ionic Activity Coefficients of Electrolyte Solutions

In this work, the primitive SAFT equation of state along with three different hard-sphere equations was used to correlate and predict mean ionic activity coefficients of aqueous electrolyte solutions. The mean ionic activity coefficient of aqueous electrolyte solutions was considered as the contribution of hard-sphere and dispersion effects. The Mansoori (M), Wang-Khoshkbarchi-Vera (WKV) and Ghotbi-Vera (GV) hard-sphere equations were applied in correlating the mean ionic activity coefficient of electrolyte solutions. The comparison among above indicated equations was shown. First, vapor pressure and densities of water in the temperature range of 373.15 to 423.15 K was regressed by SAFT equation of state. In the restrictive primitive mean spherical model, ions were hard spheres without any chain structure. Neither association effects were considered in this study. Clearly, in common used five SAFT parameters were decreased to three, which were calculated by using the experimental mean ionic activity coefficients of electrolyte solutions. The comparison among three hard-sphere equations of state approved that Ghotbi-Vera hard-sphere model (GV) correlated the experimental data accurately than the others; two hard-sphere models. The mean ionic activity coefficients of some electrolyte solutions were being predicted by taking the advantage of the regressed values surely, in a wide range of molality.