Results 1 - 10 of 5062
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[en] Data on methods for the preparation of naphthaldehydes, their physicochemical properties, structural characteristics and reactivities are generalised. Particular attention is given to procedures for formylation of naphthalenes and peri-interactions involving the aldehyde group in the α-position.
[en] In this research the emission spectra of anthracene pyrene and tetracene, has been studied. The effect of temperature, concentraation and species configuration on the emission spectrum of each of the above substances, have also been studied. In addition to this the effect of hight exposure duration of anthracene solution in chloro-form, and the effect of solvent of pyren and tetracene on their emission spectra have also been studied. The emission spectra of pyrene always showed excimer flouorescence spectrum. (4 tabs., 31 figs., 89 refs.)
[en] Using functionalized tips, the atomic resolution of a single organic molecule can be achieved by noncontact atomic force microscopy (nc-AFM) operating in the regime of short-ranged repulsive Pauli forces. To theoretically describe the atomic contrast in such AFM images, we propose a simple model in which the Pauli repulsion is assumed to follow a power law as a function of the probed charge density. As the exponent in this power law is found to be largely independent of the sample molecule, our model provides a general method for simulating atomically resolved AFM images of organic molecules. For a single perylene-tetracarboxylic-dianhydride (PTCDA) molecule imaged with a CO-terminated tip, we find excellent agreement with the experimental data. Our model eliminates the need to take into account the full tip and sample system and therefore reduces computational cost by three orders of magnitude. (paper)
[en] The single anthracene crystals under examination showed changes in prompt fluorescence intensity not exceeding 3%; and single crystals of pure tetracene and pentacene-doped tetracene changes of 1% to 40% of the total luminescence, depending upon the range of the luminescence spectrum observed. In the case of tetracene with an admixture of pentacene, the modulation of the spectral distribution is such that a distinct change in the color of the luminescence can be observed. The intensity and time changes of the modulated luminescence depend upon the kind of electrode contacts the polarization and value of voltage applied, the kind of exciting light, and the properties of the crystal itself. The phenomenon observed and dependencies obtained are interpreted in terms of the molecular exciton-charge carrier interaction concept. (author)
[en] The review demonstrates the progress in the chemistry of calixresorcinarenes over the last decade. Special attention is paid to their synthesis, conformational behaviour, functionalization and ability to serve as cavitands and capsules, to form monolayers and host-guest complexes. Practical applications of calixresorcinarenes and their derivatives in various fields are surveyed.
[en] The supramolecule, p-t-Butyl calix(8)arene, forms inclusion complex with the antiseizure drug molecule, ethosuximide. This feature is explained on the basis of optical absorption spectroscopy. Here p-t-Butyl calix(8)arene is the host molecule and ethosuximide is the guest molecule. The stoichiometry of the host–guest complex and the binding constant has been determined using Benesi–Hildebrand plot. Based on the result obtained the structure of the inclusion complex has been proposed. -- Highlights: ► Third generation supramolecule, t-butyl calix (8) arene, is used as a host molecule. ► Anti seizure drug molecule is used as a guest molecule. ► Inclusion complex is formed between the host and guest molecule