Materials Literature
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The magnetic properties of a Mn12 single-molecule magnet with a loop structure are characterized by a computational study based on density functional theory. A study of the two reported crystal structures of such a complex correctly reproduces the experimental spin ground state. We have analyzed the effect of the choi…
Based on high statistical quality wide-angle X-ray scattering data for the unfolding–refolding process of hen egg-white lysozyme (HEWL), we have analysed the change of the hydration shell as a function temperature using the program CRYSOL. The present results suggest that the decrease of the hydration-shell density st…
Nucleation is the rate-limiting step in protein crystallization. Introducing heterogeneous substrates may in some cases lower the energy barrier for nucleation and thereby facilitate crystal growth. To date, the mechanism of heterogeneous protein nucleation remains poorly understood. In this study, the nucleating prop…
The archaeon Methanocaldococcus jannaschii uses three different 2-oxoacid elongation pathways, which extend the chain length of precursors in leucine, isoleucine, and coenzyme B biosyntheses. In each of these pathways an aconitase-type hydrolyase catalyzes an hydroxyacid isomerization reaction. The genome sequence of…
Automation of iterative model building, density modification and refinement in macromolecular crystallography has made it feasible to carry out this entire process multiple times. By using different random seeds in the process, a number of different models compatible with experimental data can be created. Sets of mode…
Micron-sized latex particles with single-stranded DNA grafted to the surface have been used as a model system to study DNA mediated interactions. A new approach of tuning the interactions between particles is proposed, which allows for a gradual change of the assembly rate for fixed physical conditions of a solution b…
The Protein Data Bank and Cambridge Structural Database were analyzed with the aim of verifying whether the restraints that are most commonly used for protein structure refinement are still appropriate 15 years after their introduction. From an analysis of selected main-chain parameters in well ordered fragments of te…
Self-assembled nanofibers of peptide-amphiphile molecules have been of great interest because of their bioactivity both in vitro and in vivo. In this work, we demonstrate the simultaneous self-assembly, alignment, and patterning of these nanofibers over large areas by a novel technique termed sonication-assisted solut…
The design, synthesis, and characterization of a novel dinuclear Eu(III) bismacrocyclic conjugate 1.Eu2 as a delayed luminescent lanthanide sensor for dicarboxylates is discussed. The sensor was shown to bind small dicarboxylic acids such as aspartic, malonic, succinic, or glutaric acid in pH 6.5 solutions. However, o…
This study focuses on the geometric (molecular) structures, spectroscopic properties, and electronic structures of copper(II)-nitrito complexes as a function of second coordination sphere effects using a set of closely related coligands. With anionic hydrotris(pyrazolyl)borate ligands, one nitrite is bound to copper(I…
The direct alkylation of 1,3-dicarbonyl compounds with benzylic alcohols is shown to be efficiently catalyzed by simple Brønsted acids such as triflic acid (TfOH) and p-toluenesulfonic acid (PTS) to give rise to monoalkylated dicarbonyl derivatives in high yields. In the absence of the nucleophile, substituted alkenes…
The temperature dependence of the optical conductivity spectrum of an itinerant ferromagnetic material, ZrZn$_2$, was obtained and the dynamical effective mass and the scattering rate were derived. A renormalized Drude peak with a heavy effective mass developed at low temperatures. The effective mass rapidly increased…
In the application of heterogeneous catalysts in liquid phase reactions, the rate of reaction as well as selectivity is often negatively influenced by mass transfer limitations in the stagnant liquid in the pores of the catalyst support. Internal mass transfer limitations can be reduced by maximizing the porosity and…
A strategy of rationally engineering protein surfaces with the aim of obtaining mutants that are distinctly more susceptible to crystallization than the wild-type protein has previously been suggested. The strategy relies on replacing small clusters of two to three surface residues characterized by high conformational…
We studied the influence of nanosteps on signal intensity in gap-mode tip-enhanced Raman spectroscopy (TERS). A benzenethiol monolayer adsorbed on an Au substrate was investigated. The correlation between the TERS signal and the local topography on the substrate shows that a 2 nm high sharp step on the Au surface can…
A universal metal−molecule−metal sandwich architecture by the self-assembly of Ag nanoparticles (NPs) and Au NPs of various shapes interconnected with 4-aminothiophenol (4-ATP) molecules was presented. These Ag NPs/4-ATP/Au NPs sandwich structures were characterized by surface enhanced Raman scattering (SERS) using an…
Binding of gold and silver clusters with amino acids (glycine and cysteine) was studied using density functional theory (DFT). Geometries of neutral, anionic, and cationic amino acids with Au3 and Ag3 clusters were optimized using the DFT-B3LYP approach. The mixed basis set used here was denoted by 6-31+G** (union or…
Covalent attachment of sulfonic acid-containing aryl radicals on the surface of ordered mesoporous carbon (CMK-5), leads to a solid acid catalyst with a high acid density. The material exhibits high surface area, uniform pore size distribution, high activity and good stability for acid-catalyzed reactions, such as est…
Polymer nanocomposites (PNCs), i.e. nanoparticles (spheres, rods, and plates) dispersed in a polymer matrix, have garnered substantial academic and industrial interest since their inception, ca. 1990. With respect to the neat matrix, nanoparticle dispersion has been shown to enhance physical (e.g., barrier, erosion re…
Epitaxial assembly involved in the formation of aggregates of single-crystalline barium titanate (BaTiO 3 ) nanoparticles under hydrothermal condition is reported. The aggregates of BaTiO 3 nanocrystals were synthesized by heating a mixture of barium hydroxide, Ba(OH) 2 , and titanium tetra-iso-propoxide, Ti(O i C 3 H…