Anchoring of a [Mn(salen)Cl] complex onto mesoporous carbon xerogels

Carbon xerogels were synthesized by the conventional sol-gel approach using formaldehyde and resorcinol. The wet gel was dried by two different procedures followed by carbonization, leading to mesoporous carbon xerogels with considerably different pore size distributions. The materials were subsequently oxidized with air, in order to introduce functional groups on the surface, in particular phenols, anhydrides and carbonyls. The capacity of the carbon xerogels for direct immobilization of metal complexes was tested with a manganese(III) salen complex which possesses an extended ligand pi system and two reactive hydroxyl groups on the aldehyde fragment. The manganese loadings of the various samples indicate that larger amounts of Mn(III) complex were immobilized in the oxidized carbon xerogels when compared with the parent unactivated materials, suggesting that complex immobilization took place preferably by covalent bond between the surface oxygen functional groups and the ligand reactive groups, rather than by pi-pi interactions. The size and shape of the carbon xerogel pores were also shown to play an important role in the final loading of the manganese(III) salen complex.     

Breakup of 42 MeV 7Li projectiles in the fields of 12C and 197Au nuclei

Inclusive cross sections of α particles and tritons from the breakup of 42 MeV ⁷Li by ¹²C and ¹⁹⁷Au targets are presented and analysed in the framework of the Serber model. Spectral distortions due to the targets and relevant reaction mechanisms are discussed.     

A novel sheet 4f-3d mixed-metal pyridine dicarboxylate: synthesis, structure, photophysical properties and its transformation to a perovskite oxide

The synthesis, characterization and photophysical properties of a 4f-3d mixed metal compound, Gd(H2O)3Co[C5N1H3(COO)2]3, are described; the structure is unique, consisting of sheets with large pores (ca. 7 Angstroms diameter) in the sheets and transforms to a perovskite oxide at moderate temperatures.     

Synthesis of oxygen heterocycles

A generalised scheme for the synthesis of flavones, flavonones and chromones involving 3-acyl-γ-pyrone intermediates has been developed. Convenient synthesis of other oxygen heterocycles using similar procedure have been outlined.     

From an eight-component self-sorting algorithm to a trisheterometallic scalene triangle

Using motifs from 3-fold completive self-sorting in an eight-component library, we report on the design and fabrication of a fully dynamic trisheterometallic scalene triangle, a demanding supramolecular structure that complements the so far known triangular structures.     

Novel photocatalysts for the decomposition of organic dyes based on metal-organic framework compounds

Three novel metal-organic frameworks (MOFs) [Co(2)(C(10)H(8)N(2))][C(12)H(8)O(COO)(2)](2), 1, [Ni(2)(C(10)H(8)N(2))(2)][C(12)H(8)O(COO)(2)](2).H(2)O, 2, and [Zn(2)(C(10)H(8)N(2))][C(12)H(8)O(COO)(2)](2), 3, with three-dimensional structures have been synthesized and characterized. The structures of the three compounds appear somewhat related, formed by the connectivity involving the metal polyhedra (Co(4)N trigonal bipyramids in 1, NiO(4)N(2) octahedra in 2, and ZnO(4) tetrahedra and ZnO(3)N(2) trigonal bipyramids in 3), 4,4'-oxybis(benzoate), and 4,4'-bipyridine. The photocatalytic studies on 1-3 indicate that they are active catalysts for the degradation of orange G, rhodamine B, Remazol Brilliant Blue R and methylene blue. The compounds have also been characterized by powder X-ray diffraction, IR, thermogravitmetric analysis, UV-vis, photoluminescence, and magnetic studies.     

Multiple dynamic regimes in colloid‐polymer dispersions: New insight using X‐ray photon correlation spectroscopy

We present an X‐ray photon correlation spectroscopy (XPCS) study of dynamic transitions in an anisotropic colloid‐polymer dispersion with multiple arrested states. The results provide insight into the mechanism for formation of repulsive glasses, attractive glasses, and networked gels of colloids with weakly adsorbing polymer chains. In the presence of adsorbing polymer chains, we observe three distinct regimes: a state with slow dynamics consisting of finite particles and clusters, for which interparticle interactions are predominantly repulsive; a second dynamic regime occurring above the saturation concentration of added polymer, in which small clusters of nanoparticles form via a short‐range depletion attraction; and a third regime above the overlap concentration in which dynamics of clusters are independent of polymer chain length. The observed complex dynamic state diagram is primarily governed by the structural reorganization of a nanoparticle cluster and polymer chains at the nanoparticle‐polymer surface and in the concentrated medium, which in turn controls the dynamics of the dispersion. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016 , 54, 752–760     

Effect of porosity and pore morphology on the low-frequency dielectric response in sintered ZrO<Subscript>2</Subscript>—8 mol% Y<Subscript>2</Subscript>O<Subscript>3</Subscript> ceramic compact

Effect of porosity and pore size distribution on the low-frequency dielectric response, in the range 0.01–100 kHz, in sintered ZrO₂—8 mol% Y₂O₃ ceramic compacts have been investigated. Small-angle neutron scattering (SANS) technique has been employed to obtain the pore characteristics like pore size distribution, specific surface area etc. It has been observed that the real and the imaginary parts of the complex dielectric permittivity, for the specimens, depend not only on the porosity but also on the pore size distribution and pore morphology significantly. Unlike normal Debye relaxation process, where the loss tangent vis-à-vis the imaginary part of the dielectric constant shows a pronounced peak, in the present case the same increases at lower frequency region and an anomalous non-Debye type relaxation process manifests.     

Influence of the Charge Transfer Capacity of Alkali and Alkaline Earth Metals as Promoters in Thehydrogenation of Phenol over Palladium and Nickel Catalysts

The gas phase hydrogenation (523-573 K) of phenol has been studied over 1 wt.% Pd/Al₂O₃ and 1 wt.% Ni/SiO₂ catalysts doped with Group I and II promoter oxides. A direct correlation between catalytic activity and the charge transfer capacity of the promoters is presented where hydrogenation is favored by increasing electron donation from the promoter. The Pd catalysts generated cyclohexanone (selectivity > 97%) as the predominant product; selectivity was unaffected by the presence of the alkali or alkaline earth dopants. The Ni system exhibited appreciable hydrogenolysis behavior and charge transfer from the dopants limited the degree of hydrodeoxygenation to favor complete hydrogenation to cyclohexanol.