The synthesis, structure elucidation and antitumoral activity of novel heterocyclic compounds containing a carbazole nucleus are reported. Oxazinocarbazoles were synthesized by application of the Mannich reaction to the corresponding hydroxylated derivatives leading to 41 new molecules. Their cytotoxic activity was evaluated against various human tumor cell lines including three leukemic cell lines: CEM and Jurkat (type T), Raji (type B); breast cancer cell line (MCF-7); colorectal cancer cell line (Caco-2). A primary screening at 100 microM allowed the selection of the 10 most active compounds, which showed an antiproliferative activity on all the cell lines. A dose-effect study between 12.5 and 100 microM sorted two compounds with a significant activity: 5t and 7e against leukemic cell lines CEM, Jurkat and Raji with IC50 values around 12 microM.

L’objectif de cette these est de realiser des revetements de nitrure de bore sur differents types de substrats comme le graphite, le quartz, le pyrex, en allant jusqu’aux metaux et en particulier le titane. Le choix de la voie PDCs s’avere interessant grâce a la maitrise du precurseur de depart au niveau atomique d’une part et a la facilite du procede de depot, d’autre part. Nos objectifs etaient d’etudier la faisabilite de realiser des revetements BN sur differents types de substrat en utilisant un traitement thermique resistif et de mettre en place un dispositif qui nous permette de pyrolyser les films polymeriques sur metaux sans dommage pour le substrat, en vue de leur protection contre l’oxydation ou d’autres applications mecaniques. Dans ce sens, nous avons demontre la possibilite d’utiliser un traitement thermique alternatif par lampe halogene emettant dans l’infra-rouge pour densifier les revetement BN deposer sur substrats metalliques.

The present paper is focused on the synthesis of a series of poly[N-(alkylimino)alanes] of the type [HAlNR]n as preceramic polymers for the preparation of aluminum nitride (AlN). Polymers were characterized by means of Fourier transform infrared spectra (FT-IR), liquid-state 1H and 13C NMR spectrometry and elemental analyses. The polymers were prepared in different physical states going from viscous liquid to solid (soluble and/or fusible) compounds with the decrease of the carbon content in the polymer chain. Such properties offer potentialities in the preparation of complex forms of ceramics including thin coatings and 1D nanostructures. AlN thin coatings and 1D nanostructures were obtained from a solution of poly[N-(isopropylimino)alane] in toluene followed by heat-treatment in flowing ammonia up to 1000°C resulting in a ceramic yield of 50.6%. Subsequent heat-treatment to 1800°C in flowing nitrogen allowed the production of crystalline AlN coatings and nanorods identified by Raman spectrometry and X-ray diffraction.

BN-based coatings on metallic (titanium, aluminium and copper) substrates are prepared by infrared irradiation of a dip-coated polyborazylene. This innovative strategy creates an access towards the molecular design of hexagonal-boron nitride coatings as protective materials for low melting point metals.

Hexagonal boron nitride (h-BN) thin films (<10 mu m) were successfully obtained on various substrates (graphite-standard and HOPG, quartz and SiC) using the preceramic polymer route. Thin films were formed using precursor solutions of poly(2,4,6-trimethylamino)borazine (polyMAB) as a source of BN. Various preparation conditions were used (i.e. solvent, precursor nature and concentration, substrate and deposition method) and their impact on final BN film quality measured. Surface morphology was observed by Scanning Electronic Microscopy (SEM) and Atomic Force Microscopy (AFM). Presence of BN material was confirmed by infrared and Raman spectroscopies and the structure observed by High Resolution Transmission Electronic Microscopy (HRTEM). The chemical composition of samples analyzed by X-ray Photoelectron Spectroscopy (XPS) gives a B/N ratio close to 1. Boron nitride films were also prepared using borazine (B3N3H6) as precursor. Initial results are presented and compared with those obtained from polyMAB solutions. (C) 2007 Elsevier B.V. All rights reserved.