Faouzi Aloui

Synthesis and X‐Ray Analysis of a New [6]Helicene

Abstract A new disubstituted hexahelicene derivative 3 bearing methoxy functions at positions 3 and 14 has been prepared in racemic form through a Heck reaction followed by photocyclodehydrogenation. Suitable crystals of rac‐3 were analyzed by X‐ray crystallography and showed similar geometry to the structure of hexahelicene itself. Deprotection of 3 using boron tribromide led to 3,14‐dihydroxyhexahelicene 4 in quantitative yield. The complexation of transition metal atoms seemed to be quite possible by these two bidentate hexahelicene derivatives.

Synthesis and Characterization of a New Racemic Helically Chiral Ru(II) Complex and Its Catalytic Degradation of Eriochrome Blue Black B

Abstract A new helically chiral ruthenium complex of fused aromatic rings was prepared in a one stepsequence and fully characterized. The new complex was used as an heterogeneous catalyst for the degradation of Eriochrome Blue Black B (one of the azoic dyes) in aqueous medium in the presence of hydrogen peroxide. Using a fixed dose of H2O2, experiments revealed that the dye degradation was affected by the reaction temperature and the initial dye concentration. The energetic parameters were also determined, and the activation energy (E a) was found to be low (31 kJ mol−1), confirming that the prepared catalyst was very efficient for the degradation of anionic dyes using H2O2. The complex exhibited excellent catalytic activity and has the advantage of easy separation from the reaction medium. In addition, the ruthenium helical complex–H2O2 system could remain with good catalytic activity after five cycles. GRAPHICAL ABSTRACT

New Helically Chiral Metallated Complexes: Characterization and Catalytic Activity

Abstract New helically chiral and air-stable Pd(II) and Ru(II) complexes were prepared in good yields and fully characterized. The optical properties of these new complexes were investigated, showing interesting behavior. The Ru complex was used as heterogeneous catalyst for the decoloration of calmagite (one of the azoic dyes) solutions at pH 6.5 in the presence of hydrogen peroxide (H2O2). Experiments revealed that the decoloration process was affected by the H2O2 dose, the reaction temperature, and the initial dye concentration. The energetic parameters were also determined and the activation energy, E a, was found to be low, confirming that the prepared catalyst was very efficient for color removal. The new ruthenium complex exhibited excellent catalytic activity and has the advantage of easy separation from the reaction medium. It could remain with good catalytic activity after five cycles. GRAPHICAL ABSTRACT

Removal of a wide range of dyes using 4-methyl-2-(naphthalen-2-yl)-N-propylpentanamide-functionalized ethoxy-silica and raw silica

Abstract The present research offers a comparative study on the character of the performance of dye removal using either functionalized silica or raw silica gel as adsorbents. First, these supports were characterized in terms of FT-IR and SEM analyses. Then, four different dye solutions were checked for the adsorption phenomenon: Eriochrome Black B (an acid dye), Methylene Blue (a basic dye), Direct Yellow 50 (a direct dye), and Reactive Blue 49 (a reactive dye). Experimental data revealed a dependence on the experimental conditions. Functionalized silica presented a higher removal of dyes than the raw silica. Among the four studied dyes, the highest capacity removal was achieved with Eriochrome Blue Black B (140 mg g−1) using functionalized silica as adsorbent. This value was reduced to 55 mg g−1 for raw silica. Further, kinetic and thermodynamic investigations of Eriochrome were discussed. Results gleaned from this study suggest that the functionalized silica could be considered as an efficient candidate to treat colored waters.

Synthesis and Characterization of a New Chiral Pentacyclic Phosphine

Abstract A new helically chiral pentacyclic phosphine, containing one thiophene ring, was prepared in good yield and purity via a five-step sequence involving a Wittig reaction, a palladium-catalyzed Mizoroki–Heck coupling, and classical oxidative photocyclization reactions. The investigation using ultraviolet–visible spectroscopy shows that the helicene precursor of the target helical phosphine as well as its phosphine oxide have interesting behaviors. GRAPHICAL ABSTRACT

Synthesis and Optoelectronic Properties of Some New Thiahelicenes

Abstract New symmetrical helically chiral penta- and heptacyclic aromatic systems containing two thiophene rings have been prepared, in good yields, under mild conditions using a photochemical route. Optoelectronic properties of these helically aromatic thia-systems were determined and exhibit interesting behavior.

Preparation, characterization and evaluation of the catalytic power of an hybrid compound [H3PMo12O40-chitosan] for the azoic-colored solutions

Abstract Inorganic–organic hybrid structures have become novel alternatives for many applications as they combine the advantages of both systems. In this current study, a hybrid compound [H3PMo12O40-chitosan] was prepared using a wet impregnation method with different proportions (0-100 wt. %, considering the polymer as the main component). The chemical structure and the morphology of the synthesized compounds were studied using FT-IR and SEM. Their catalytic powers were evaluated for Naphtol Blue Black and Eriochrome Blue Black B. Experimental data revealed that the decolorization phenomenon depends on the structure of the dye it-self, the pH value, the initial dye concentration, the time contact, the oxidant dose and the temperature. Kinetic data, well described using the first order model, allowed us to establish the thermodynamic parameters. The calculated low values of Ea (7.48 and 8.14 KJ. mol-1) proved the efficiency of the prepared catalyst. Eriochrome Blue Black B could be decomposed more rapidly than Naphtol Blue Black. As example, after a period of 30 min of reaction, the target removals were, respectively, 70% and 15% for mono and bi-azoic dyes. The reuse of the catalyst is carried out and it was found to be recyclable more than three consecutives cycles.

Synthesis, X-Ray Analysis, and Evaluation of the Optoelectronic Properties of a New Thia[6]helicene

Abstract The synthesis and structural characterization of a new hexahelicene derivative is reported. This compound features a new type of structure bearing a bromine atom. Suitable crystals of the latter indicate that its conformation closely resembles that of the unsubstituted [6]helicene, whose idealized symmetry is C2. The optoelectronic properties of this helical hexacyclic system were determined and exhibit a very interesting behavior. GRAPHICAL ABSTRACT