Materials Literature
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Ethyl 1-[(4-hydroxyphenyl)aminocarbonyl)]-2-vinylcyclopropane carboxylate has been oligomerized using horseradisch peroxidase as catalyst. The oligomerization was achieved in the presence of cyclodextrine at room temperature in phosphate buffer (pH 7). The oligomer formed was cross-linked via free radical polymerizati…
This Communication describes a pseudotetrahedral d7 complex, [PhBP3]Co(OSiPh3), that exhibits thermally induced spin-crossover both in solution and in the solid state. Magnetic crossover behavior is achieved by confluence of the X-type ligand and the tripodal auxiliary employed. Four-coordinate platforms of the presen…
A general strategy to reduce the size of the inactive space in extended Configuration Interaction calculations is presented. The approach is based on the use of local orbitals, obtained from a recently reported iterative method. Both occupied and virtual local orbitals are classified according to their topological nat…
A series of metal−polyboron clusters with the general formula MB 6 (M = Be, Mg, Ca, and Sr) were investigated using ab initio self-consistent field and density functional theory (DFT) methods. Calculation results show that the two clusters of BeB 6 and MgB 6 have C 6 v pyramidal structure with M 2+ cation interacting…
Abstract The Raman spectra of CdS 1− x Se x nanocrystals, embedded in a borosilicate glass matrix, are studied, CdS‐like and CdSe‐like LO phonon frequencies being used to determine the nanocrystal composition. The Raman lineshape is analyzed taking account of confinement‐related phonons with nonzero wavevector, surfac…
The aqueous solution of poly(lactic acid- co -glycolic acid)- g -poly(ethylene glycol) becomes a gel as the temperature increases. The sol-to-gel transition temperature can be controlled from 15 to 45 °C by varying the number of poly(ethylene glycol) grafts and the composition of the polymer. In addition, hysteresis b…
In this review, we will describe calculations using time-dependent density-functional theory (DFT) combined with pseudopotentials to determine excited state properties of matter. While a computational framework for ground state properties of condensed matter is well established, calculations for excited state properti…
Co-cyclization of 1,2,5-thiadiazole-3,4-dicarbonitrile and 3,6-diamyloxyphthalodinitrile in the presence of magnesium or lithium amylate in amyl alcohol leads to mixtures containing the Mg derivatives of the symmetrical species tetrakis(1,2,5-thiadiazolo)porphyrazine, (S(4))PzH(2), and tetrakis(1,4-diamyloxybenzo)porp…
We have measured the resonance spectrum of glide-plane forbidden x-ray diffraction in hexagonal ZnO as a function of temperature. This is the only method to observe deformations of the electronic states caused by thermal atomic motion. The results provide the first evidence for a complex line shape in the spectrum of…
Luminescent lanthanide complexes have unusual spectroscopic characteristics, including millisecond excited-state lifetime and sharply spiked emission spectra. These characteristics make them valuable alternatives to conventional organic fluorescent probes in detection applications and for measuring nanometer-scale con…
The specific heat of single-walled carbon nanotubes (SWNT's) is studied theoretically in this paper. Making use of the continuum model, phonon dispersion relations are derived numerically and analytically. Finally, expressions for specific heat versus temperature are derived theoretically, and we find that the lattice…
Based on first-principles pseudopotential total energy calculations, the effects of Al substitution in Ti 3 SiC 2 , yielding chemical formula Ti 3 Si 0.75 Al 0.25 C 2 , were studied by examining the equilibrium properties and electronic structure. The lattice configurations, cohesive energy, atomic bonding properties…
The structural properties of ten helicenebisquinones that have side chains differing in number and structure are analyzed by means of polarized light microscopy, differential thermal analysis, and X-ray diffraction. All the derivatives whose side chains are bonded to the helical cores by ether linkages assemble into h…
Dielectric properties of the relaxor ferroelectric ceramics PLZT 8/65/35 and 9.5/65/35 were studied in the broad frequency range of 100 Hz–1 THz at low temperatures below the freezing temperature. Nearly frequency-independent dielectric losses were observed up to 1 GHz on cooling down to 10 K. Their magnitude decrease…
Abstract The solid‐state procedure is used to produce bulk ceramics of CCTO (CaCu 3 Ti 4 O 12 ). The samples of the CCTO ceramic are studied by X‐ray powder diffraction and infrared and Raman scattering spectroscopy. The infrared and Raman scattering spectroscopy confirm the formation of the CCTO phase, as seen by X‐r…
The creation of realistic models of amorphous silica has been studied using the Monte Carlo based method of Wooten, Winer, and Weaire, where the bond-topology is optimized with respect to an interatomic potential model. The commonly used Keating potentials are compared and their strengths and weaknesses are assessed.…
In this letter we report the synthesis of nanostructures of molybdenum trioxides by directly oxidizing a spiral coil of molybdenum, at ambient atmosphere, by passing a current through the coil. The advantage of this approach is that the temperature of the substrate is low (normally below 200°C), and that the nanostruc…
Abstract A family of bisphenol‐containing ligands with XO 2 donor atoms, where X = S, Se, or N, yields [Ni II ] 4 ( 1 ) and ( 2 ), [Ni II ] 5 ( 3 ), and [Ni II ] 6 ( 4 ) complexes. Complex 2 , 3 , and 4 have been structurally characterised by X‐ray diffraction. The compounds were characterised spectroscopically and by…
The first azide(mu1,1)-bridged binuclear cobalt(II) complex with a chelated imino nitroxide radical, [Co2(immepy)2(N3)(4)].2EtOH, was structurally and magnetically characterized, where immepy = 4,4,5,5-tetramethyl-2-(6'-methyl-2'-pyridyl) imidazoline-1-oxyl. Five nitrogen atoms complete the coordination sphere of the…
Magnetic susceptibility and EPR studies show that trinuclear Cu(II)-pyrazolato complexes with a Cu(3)(mu3-X)2 core (X = Cl, Br) are ferromagnetically coupled: J(Cu-Cu) = +28.6 cm(-1) (X = Cl), +3.1 cm(-1) (X = Br). The orderly transition from an antiferromagnetic to a ferromagnetic exchange among the Cu centers of Cu(…