Correction for ‘Synthesis and characterization of novel Li-stuffed garnet-like Li5+2xLa3Ta2−xGdxO12 (0 ≤ x ≤ 0.55): structure–property relationships’ by Dalia M. Abdel Basset, et al., Dalton Trans., 2017, 46, 933–946.
ABSTRACTThe structure-property relationships of several conducting transition metal oxides, as well as their preparative methods, are presented in this paper. The importance of preparing homogeneous phases with precisely known stoichiometry is emphasized. A comparison is also made of the various techniques used to prepare both polycrystalline and single crystal samples. For transition metal oxides, the metallic properties are discussed either in terms of metal-metal distances which are short enough to result in metallic behavior, or in terms of the formation of a П* conduction band resulting from covalent metal-oxygen interactions. Metallic behavior is observed when the conduction bands are populated with either electrons or holes. The concentration of these carriers can be affected by either cation or anion substitutions. The discussion in this presentation will be limited to the elements Re, Ti, V, Cr, Mo, and Cu.
ABSTRACTImidazoles present a tunable, versatile and economical platform for the development of novel liquid solvents and polymer membranes for CO2 capture. An overview of our studies in this area is presented, with emphasis on characterization of structure-property relationships in imidazole-based materials through both experimental and computational studies. To this end, a growing library of systematically varied imidazole compounds has been synthesized using only commercial available starting materials and straightforward reactions. Using this library of compounds, we have sought to understand and develop predictive models for thermophysical properties relating to process design, including: density, viscosity, vapor pressure, pKa and CO2 absorption capacity. Furthermore, we have discovered that imidazoles are stable in the presence of SO2 and can form reversible 1:1 adducts, which can be beneficial as SO2 is typically present at ppm levels alongside CO2 in flue gas from coal-fired power plants.
Abstract
Structure-property relationships were investigated in hyperbranched polyisobutylenes, in comparison with commercial linear butyl rubber. The gel-free, soluble hyperbranched polyisobutylenes, synthesized by living carbocationic polymerization, had molecular weights, Mw≈400,000 to 1,000,000 g/mol, molecular weight distributions, MWD ≈1.2 to 2.6, and branching frequencies, BR ≈ 4 to 60. The mechanical and viscoelastic characterization of these polymers revealed interesting properties, including the characteristics of crosslinked rubbers.
Aerogels are porous materials with potential applications in fields ranging from thermal insulation, catalyst support, filters, electrical storage, components in optical devices, mechanical damping all the way to drug release. However, careful reliable characterization is the base for both, understanding of fundamental structure - property relationships as well as a directed development of materials and composites for specific applications. The review therefore addressed severe problem upon aerogel characterization that have been identified in the past and presents reliable non-destructive alternatives and novel methods that can be applied for the characterization of aerogels as well as their gel precursors.
Detailed understanding of the local structure–property relationships in soft biopolymeric hydrogels can be instrumental for applications in regenerative tissue engineering.
AbstractStudies have shown that complex Zintl phases exhibit a rich diversity of crystal structures. These have also revealed a remarkable success of the Zintl concept in rationalizing stoichiometry, crystal structure and chemical bonding of many main group intermetallics. Still there are unresolved questions about the usefulness of the concept in explaining structure-property relationships in intermetallics near the Zintl border, and as a rational tool in designing new materials. Limitations of the concept are represented by violations often associated with “electron-deficient” phases that contain Group 13 metalloids. Recent investigations on “electron-deficient” Zintl phases containing post transition metals have led to the synthesis of a number of novel inorganic-intermetallic π-systems. Since unique structures and properties are already apparent in normal Zintl phases, it is anticipated that the exploratory synthesis and characterization of conjugated and multiple-bonded inorganic systems will produce not only unusual crystal chemistry but interesting physical properties as well. We report on new complex Zintl phases that include the semiconducting SrCa2In2Ge - which features [In2Ge]6- chains and represents a novel inorganic conjugated π-system analogous to a polyallyl chain with In-In double bonds, and Ca5In9Sn6 - which contains In trimers, [In3]5- analogous and isoelectronic with the aromatic cyclopropenium cation, [C3H3]+. These unusual materials, Zintl π-systems, represent a promising class of electronic materials with a range of potential applications.
Hydrogenation of levulinic acid (LA) obtained from cellulose biomass is a promising path for production of γ-valerolactone (GVL)—a component of biofuel. In this work, we developed Ru nanoparticle containing nanocomposites based on hyperbranched pyridylphenylene polymer, serving as multiligand and stabilizing matrix. The functionalization of the nanocomposite with sulfuric acid significantly enhances the activity of the catalyst in the selective hydrogenation of LA to GVL and allows the reaction to proceed under mild reaction conditions (100 °C, 2 MPa of H2) in water and low catalyst loading (0.016 mol.%) with a quantitative yield of GVL and selectivity up to 100%. The catalysts were successfully reused four times without a significant loss of activity. A comprehensive physicochemical characterization of the catalysts allowed us to assess structure-property relationships and to uncover an important role of the polymeric support in the efficient GVL synthesis.
Biodegradable poly(L-lactic acid) (PLLA)/mesoporous silica nanocomposites were prepared by grafting L-lactic acid oligomer onto silanol groups at the surface of mesoporous silica (SBA-15). The infrared results showed that the lactic acid oligomer was grafted onto the mesoporous silica. Surface characterization of mesoporous silica proved that the grafted oligomer blocked the entry of nitrogen into the mesopores. Thermal analysis measurements showed evidence that, once mixed with PLLA, SBA-15 not only nucleated the PLLA but also increased the total amount of crystallinity. Neat PLLA and its nanocomposites crystallized in the same crystal habit and, as expected, PLLA had a defined periodicity compared with the nanocomposites. This was because the grafted macromolecules on silica tended to cover the lamellar crystalline order. The g-SBA-15 nanoparticles improved the tensile moduli, increasing also the tensile strength of the resultant nanocomposites. Overall, the silica concentration tended to form a brittle material.
Correction: Synthesis and characterization of novel Li-stuffed garnet-like Li5+2xLa3Ta2−xGdxO12 (0 ≤ x ≤ 0.55): structure–property relationships
