Materials Literature
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Stepwise addition/elimination and concerted mechanisms for the methanolysis of ε-caprolactone, as a model for the initiation and propagation of ring-opening polymerization (ROP), have been investigated computationally using the B3LYP/6-31G* density functional method, with assistance from one or two ancillary methanol…
This paper describes the preparation of two tetracations 4a(4+) and 4b(4+) composed of di(1-azulenyl)methylium units based on a new structural principle of a cyanine-cyanine hybrid for the design of electrochromic materials with two color changes. Di- and monocations 5a(2+), 5b(2+) and 6a+, 6b+ composed of di(1-azulen…
Density functional theory calculations carried out on the anionic Ni(II) chain complexes {trinickeltetrakis[2,6-bis(amido)pyridine]}2- and {trinickeltetrakis[N,N'-bis(sulfonyl)pyridyldiamido]}2- show that the electron-attractor character of the sulfonyl substituent modifies the basicity of the amido ligand ends so as…
This paper describes the growth of gold and silver nanomaterials from their corresponding colloidal seeds on glass substrates. The glass substrates were treated with 3-mercaptopropyltrimethoxysilane (MPTMS) and then with gold or silver nanoparticle seeds (AuNPSs or AgNPSs) at different concentrations. After separately…
A series of novel heterocyclic combinatorial libraries containing 4H-thieno[3,2-b]pyrrole, thieno[2',3':4,5]-pyrrol[1,2-d][1,2,4]triazine and thieno[2',3':4,5]pyrrolo[1,2-a]pyrazine heterocyclic moieties were obtained by parallel solution-phase synthesis. Key steps include different reactions of initial alkyl 4H-thien…
The surface energies of α-rhombohedral, β-rhombohedral, and α-tetragonal boron were calculated from first principles, for the first time, to investigate their role in nanoscale crystal growth. The results support the existence of the pure α-tetragonal polymorph of boron. Although the existence of this polymorph had lo…
Porphyrins are stable molecules with a macrocyclic conjugated system and often peripheral substituents. This unique structure makes the electronic properties of the four meso-carbons (the methine bridges) nearly identical. Replacement of the weakly electron-polarizing 2,4-vinyl groups of protoporphyrin IX with strongl…
Pseudomonas putida CA-3 accumulates polyphosphate (polyP) and medium-chain-length polyhydroxyalkanoate (mclPHA) concurrently under nitrogen limitation. Five other mclPHA-accumulating Pseudomonas strains are capable of simultaneous polyP and mclPHA biosynthesis. It appears that polyP is not the rate-limiting step for m…
DNA liquid crystalline gel (LCG) has been newly prepared by a dialysis of concentrated DNA solutions into concentrated metal cation solutions. The condition for forming DNA LCG is examined by means of the insolubilization reaction. The shrinking ratio and the ratio of the thickness of LCG layer, delta, and the diamete…
Bioconjugates of the hemoproteins, myoglobin, and hemoglobin have been synthesized by their adsorption on spherical gold and silver nanoparticles and gold nanorods. The adsorption of hemoproteins on the nanoparticle surface was confirmed by their molecular ion signatures in matrix assisted laser desorption ionization…
Comparative studies on the electrogenerated chemiluminescence (ECL) behavior of luminol on various electrodes modified with gold nanoparticles of different size were carried out in neutral solution by conventional cyclic voltammetry (CV). The results demonstrated that the gold nanoparticle modified electrodes could ge…
The crystal structures, atomic distributions, and theoretical electronic structures of five different Cu5-xZn8+x gamma-brass compounds (x = -0.59(3), -0.31(3), 0.00(3), 0.44(3), and 0.79(3)) are reported with the goal of identifying chemical influences on the observed phase width. These structures have been refined by…
We present semipermeable, hollow capsules (colloidosomes) that expand and contract upon heating and cooling. The capsules are composed of micrometer-sized poly(N-isopropylacrylamide)-co-acrylic acid microgel particles, which exhibit a reversible size transition near 34 degrees C. The microgel particles assemble on the…
Two enantiomers of a new 4,5-pineno-2,2'-bipyridine ligand were synthesized and subsequently incorporated into hemicage ligands through a phenyl linker to yield ligands (+)-L1 and (-)-L1 or through a mesityl linker to yield ligands (+)-L2 and (-)-L2. Complexation of these ligands to Ru(II) afforded diastereomerically…
Coherent population trapping is demonstrated in single nitrogen-vacancy centers in diamond under optical excitation. For sufficient excitation power, the fluorescence intensity drops almost to the background level when the laser modulation frequency matches the 2.88 GHz splitting of the ground states. The results are…
A straightforward method for the synthesis of original 4,4-dialkoxy- or 4,4-diaryloxy-diaza-s-indacenes (BODIPY) derivatives obtained by treatment of BODIPY 1 with various alcohols in the presence of AlCl3 is described. The novel compounds are characterized by spectroscopic properties similar to those of the parent BO…
Fully-relativistic first-principles calculations of the Fe(001) surface demonstrate that resonant surface (interface) states may produce sizeable tunneling anisotropic magnetoresistance in magnetic tunnel junctions with a single magnetic electrode. The effect is driven by the spin-orbit coupling. It shifts the resonan…
By using Monte Carlo simulation on a ferromagnetic core/antiferromagnetic shell nanoparticle, we investigate in details the exchange bias of the magnetic hysteresis as a function of both core radius and shell thickness, at low temperature. It is found that the exchange bias is very sensitive to the core radius and a s…
Two modifications of CeCuSn were prepared from the elements: the high-temperature (beta) modification crystallizes directly from the quenched sample, while the low-temperature (alpha) modification forms after annealing at 700 deg C for one month. Both modifications were investigated by X-ray powder and single crystal…
Stimulated by recent advances in isolating graphene and similarities to single-wall carbon nanotubes, simulations were performed to assess the effects of static disorder on the conductance of metallic armchair- and zigzag-edge graphene nanostrips. Both strip types were found to have outstanding ballistic transport pro…