Electron transport properties of some new 4-tert-butylcalix[4]arene derivatives in thin films

Temperature dependences of electric conductivity and thermoelectric power of some recently synthesized organic compounds, 4-tert-butylcalix[4]arene derivatives, are studied. Thin-film samples (d = 0.10-0.40 mu m) spin-coated from chloroform solutions onto glass substrates were used. Organic films with reproducible electron transport properties can be obtained if, after deposition, they are submitted to a heat treatment within temperature range of 295-575 K.  The studied polycrystalline compounds show typical p-type semiconductor behavior. The activation energy of the electric conduction ranges between 0.82 and 1.12 eV, while the ratio of charge carrier mobilities was found in the range of 0.83-0.94. Some correlations between semiconducting parameters and molecular structure of the organic compounds have been discussed. In the higher temperature ranges (T>420 K), the electron transport in examined compounds can be interpreted in terms of the band gap representation model, while in the lower temperature range, the Mott\u27s variable-range hopping conduction model was found to be appropriate. The investigated compounds hold promise for thermistor applications.

DC conduction mechanism of some new lower rim substituted calixarenes derivatives in thin films

Date du colloque : 09/2014International audienc

Synthesis of UDP-glucose derivatives modified at the 3-OH as potential chain terminators of beta-glucan biosynthesis.

A series of UDP-D-glucose derivatives and precursors that have been modified at C-3 were synthesised from D-glucose as potential chain terminators of beta-glucan biosynthesis. None of the UDP-derivatives or the precursors tested displayed significant anti-fungal activity in a series of germination assays on the dermatophyte Trichophyton rubrum

Synthesis of UDP-GlcNAc derivatives modified at OH-4 as potential chain-terminators of chitin biosynthesis

A series of UDP-GlcNAc derivatives and precursors that have been modified at the 4-position were synthesised from N-acetyl glucosamine as potential chain terminators of chitin biosynthesis. None of the UDP-derivatives or the precursors tested displayed any significant anti-fungal activity in cell adhesion or germination assays on the dermatophyte Trichophyton rubrum. © 2007 Elsevier Ltd. All rights reserved

Carbohydrate chain terminators: rational design of novel carbohydrate-based antifungal agents.

(Chemical Equation Presented) The terminators. A chain-termination approach was employed to rationally design monosaccharide derivatives as inhibitors of chitin biosynthesis by replacement of the 4-hydroxyl group of N-acetyl glucosamine monomers. Antifungal activity was observed for a variety of acylated monosaccharide and oxazoline derivatives by means of fungal-spore germination and adhesion assays. © 2007 Wiley-VCH Verlag GmbH and Co. KGaA

On the direct current electric conductivity and conduction mechanism of some stable disubstituted 4-(4-pyridyl)pyridinium ylides in thin films

International audienc

Synthesis, crystal structure and antimycobacterial activities of 4-indolyl-1,4-dihydropyridine derivatives possessing various ester groups

The present study reports the synthesis of a series of alkyl 4-(5/6-bromo-1H-indole-3-yl)-2,6,6/2,7,7-trimethyl-5-oxo-1,4,5,6,7,8-hexahydroquinoline-3-carboxylate derivatives by a simple, rapid and convenient modified Hantzsch condensation reaction under microwave irradiation. The structure elucidation of the target compounds was carried out by different spectral techniques including IR, H-1-NMR, COSY, C-13-NMR, and mass analysis. Additionally, the proposed structure of compound 3 was proved by single crystal X-ray analysis. In vitro anti-tubercular activity of the compounds was evaluated against Mycobacterium tuberculosis H(37)Rv. The obtained results indicated that some compounds exhibited moderate antimycobacterial activity with weak cytotoxicity. Among them, compounds carrying ethyl or isopropyl groups in their ester moiety were found to be the most active compounds in this series. Molecular modeling studies were carried out to gain an idea about the mechanism of action of the active compounds. According to the results, the interactions were found quite similar with the co-crystalized ligand of M. tuberculosis enoyl reductase (InhA)