150 research outputs found
4-BromoÂselenoÂanisole
The title compound, 1-bromo-4-methylÂselenoÂbenzene, C7H7BrSe, was prepared by methylÂation of 4-bromoÂselenoÂphenolate with methyl iodide, and crystals suitable for structure determination were obtained by sublimation. The molÂecule is essentially planar; the SeâMe bond is rotated by only 2.59â
(19)° out of the least-squares plane of the benzene ring. The most pronounced intermolecular interactions are two hydrogen bonds of the type CâHâŻĎ, which determine a herring-bone pattern in the crystal packing
Deterministic assembly of linear gold nanorod chains as a platform for nanoscale applications
We demonstrate a method to assemble gold nanorods highly deterministically into a chain formation by means of directed capillary assembly. This way we achieved straight chains consisting of end-to-end aligned gold nanorods assembled in one specific direction with well-controlled gaps of [similar]6 nm between the individual constituents. We determined the conditions for optimum quality and yield of nanorod chain assembly by investigating the influence of template dimensions and assembly temperature. In addition, we transferred the gold nanorod chains from the assembly template onto a Si/SiO2 target substrate, thus establishing a platform for a variety of nanoscale electronic and optical applications ranging from molecular electronics to optical and plasmonic devices. As a first example, electrical measurements are performed on contacted gold nanorod chains before and after their immersion in a solution of thiol end-capped oligophenylenevinylene molecules showing an increase in the conductance by three orders of magnitude, indicating molecular-mediated transport
1,4-Bis(4-chlorophenylseleno)-2,5-dimethoxybenzene
The title compound, C20H16Cl2O2Se2, utilizes the symmetry of the crystallographic inversion center. Molecular chains are formed through symmetric C—H...Cl interactions around inversion centers, mimicking the commonly observed symmetric hydrogen-bonded dimer pattern often found in carboxylic acids
Magnetic ground state and magnon-phonon interaction in multiferroic h-YMnO
Inelastic neutron scattering has been used to study the magneto-elastic
excitations in the multiferroic manganite hexagonal YMnO. An avoided
crossing is found between magnon and phonon modes close to the Brillouin zone
boundary in the -plane. Neutron polarization analysis reveals that this
mode has mixed magnon-phonon character. An external magnetic field along the
-axis is observed to cause a linear field-induced splitting of one of the
spin wave branches. A theoretical description is performed, using a Heisenberg
model of localized spins, acoustic phonon modes and a magneto-elastic coupling
via the single-ion magnetostriction. The model quantitatively reproduces the
dispersion and intensities of all modes in the full Brillouin zone, describes
the observed magnon-phonon hybridized modes, and quantifies the magneto-elastic
coupling. The combined information, including the field-induced magnon
splitting, allows us to exclude several of the earlier proposed models and
point to the correct magnetic ground state symmetry, and provides an effective
dynamic model relevant for the multiferroic hexagonal manganites.Comment: 12 pages, 10 figure
The Challenge of Synthesizing Oligomers for Molecular Wires
Controlling the size of the oligomer and introducing functional groups at the ends of the oligomer that allow it to react with separate electrodes are critical issues when preparing materials for molecular wires. We demonstrate a general synthetic approach to oligophenylenevinylene (OPV) derivative molecules with a molecular length up to 9â10 nm which allow for the introduction of aromatic thioacetate functionality in fully conjugated oligomer systems. Oligomers containing 3â15 phenyl units were synthesized by step wise Horner-Wadsworth-Emmons (HWE) reactions of a bifunctional OPV-monomer, which demonstrated good control of the size of the OPVs. Workup after each reaction step ensures a high purity of the final products. End group functionalization was introduced as a last step
ChemInform Abstract: Synthesis and Pharmacology of Seleninic Acid Analogues of the Inhibitory Neurotransmitter Îł-Aminobutyric Acid.
ChemInform Abstract: Facile Synthesis of Îą-Hydroxy Carboxylic Acids from the Corresponding Îą-Amino Acids.
The tert-Butyl Moiety â A Base Resistant Thiol Protecting Group Smoothly Replaced by the Labile Acetyl Moiety.
Synthesis of 2,2-diarylvinyl phenyl selenides by dehydration of 2-hydroxyalkyl phenyl selenides
ChemInform Abstract: Electrophilic Organic Selenium Reagents - Protonated Seleninic Acids as Precursors for Unsymmetrical Aromatic Selenides.
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