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Interaction of single-walled carbon nanotubes with electron-donor and -acceptor molecules causes significant changes in the electronic and Raman spectra. Electron-donating molecules such as tetrathiafulvalene and aniline cause changes opposite to those caused by electron-withdrawing molecules such as nitrobenzene and tetracyanoethylene. Thus, a proportion of the semiconducting SWNTs becomes metallic on electron donation through molecular charge transfer. Electrical resistivity measurements reveal a systematic variation with electron-donating or -withdrawing power of the interacting molecules.

No abstract is provided for this article.

Simple methods of preparing boron nitride nanotubes and nanowires have been investigated. The methods involve heating boric acid with activated carbon, multi-walled carbon nanotubes, catalytic iron particles or a mixture of activated carbon and iron particles, in the presence of NH3. While with activated carbon, boron nitride nanowires constitute the primary product, high yields of clean boron nitride nanotubes are obtained with multi-walled carbon nanotubes. Aligned boron nitride nanotubes are produced when aligned multi-walled carbon nanotubes are employed as the starting material suggesting the templating role of the nanotubes. Boron nitride nanotubes with different structures have been obtained by reacting boric acid with NH3 in the presence of a mixture of activated carbon and Fe particles.

Crystallisation of trithiocyanuric acid (TTCA) from various organic solvents that have hydrogen bonding capability (acetone, 2-butanone, dimethylformamide, dimethyl sulfoxide, methanol and acetonitrile) leads to the formation of co-crystals in which the solvent molecules are incorporated together with TTCA in the crystal structure. Structure determination by single-crystal X-ray diffraction reveals that these co-crystals can be classified into different groups depending upon the topological arrangement of the TTCA molecules in the crystal structure. Thus, three different types of single-tape arrangements of TTCA molecules and one type of double-tape arrangement of TTCA molecules are identified. In all co-crystals, hydrogen-bonding interactions are formed through the involvement of N-H bonds of TTCA molecules in these tapes and the other molecule in the co-crystal. Detailed rationalisation of the structural properties of these co-crystals is presented.

No abstract is provided for this article.

Graphene look-alike: MoS2 has a layered structure similar to graphene. Tetrathiafulvalene (TTF) interacts with thin, few-layer MoS2 material by donating an electron, resulting in the formation of TTF radical cation and n-type doping of MoS2. Electron-withdrawing tetracyanoethylene, in contrast, does not cause p-type doping in MoS2. As a service to our authors and readers, this journal provides supporting information supplied by the authors. Such materials are peer reviewed and may be re-organized for online delivery, but are not copy-edited or typeset. Technical support issues arising from supporting information (other than missing files) should be addressed to the authors. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

We report the observation of substantial thermal relaxation in a single crystal of the charge ordered system Pr0.63Ca0.37MnO3 in an applied magnetic field of H=8T. The relaxation is observed when the temperature is scanned in the presence of a magnetic field in the temperature interval T MH <T<T CO, where T CO is the charge ordering temperature and T MH is the charge melting temperature in a field. In this temperature range, the system has coexisting charged ordered insulator (COI) and ferromagnetic metallic (FMM) phases. No such relaxation is observed in the COI state in H=0T or in the FMM phase at T<T MH in the presence of a magnetic field. We conclude that the thermal relaxation is due to two coexisting phases with nearly the same free energies but separated by a potential barrier. This barrier makes the transformation from one phase to the other time-dependent in the scale of the specific heat experiment and gives rise to the thermal relaxation.

By the reaction of the appropriate organometallic precursors and tetrakishydroxymethyl phosphonium chloride (THPC) at the toluene-water interface, we have prepared nanocrystalline films of Au-Ag and Au-Cu alloys with a range of compositions. The films have been characterized by X-ray diffraction, electron microscopy, optical spectroscopy, and other techniques, besides compositional analysis. The particle size of the nanocrystals in the films varies with the composition. The surface plasmon band of the alloy films as well as of the organosols obtained by the disintegration of the films by the addition of an alkanethiol show the expected composition dependence. It has been possible to prepare the nanocrystalline films of a ternary Au-Ag-Cu alloy.

We present and compare the results of temperature-dependent electron paramagnetic resonance (EPR) studies on Pr1−xCaxMnO3 for x = 0.64, which is electron-doped, with results of studies on the hole-doped, x = 0.36 composition. The temperature dependence of the various parameters obtained from the powder and single crystal spectra show significant differences between the two manganites. At room temperature the 'g' parameter for the electron-doped system is less than the free electron 'g' value 'ge ', whereas for the hole-doped system it is more than 'ge '. Further, the linewidth obtained from the powder spectra as well as the single crystal spectra show different functional dependences on temperature in the two systems. Quite strikingly, the peak observed at Tco in the temperature dependence of the asymmetry parameter, α, of the single crystal spectra in the hole-doped system, is absent in the electron-doped system. We understand this contrasting behaviour of the EPR parameters in the two systems in terms of the very different nature of microscopic interactions in them.

No abstract is provided for this article.