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

Keywords:

• Azoic dyes
• calmagite
• catalysis
• dye decoloration
• helical complexes
• helicenes
• optical properties

ACKNOWLEDGMENT

The authors are grateful to Direction Générale de la Recherche Scientifique of the Tunisian Ministry of Higher Education and Scientific Research for financial support.

Notes

^a The percentage of dye removal was determined after 240 min of contact time.

^a The percentage of dye removal was determined after 240 min of contact time.

^a The percentage of dye removal was determined after 240 min of contact time.