Visible light active CdS nanorods: one-pot synthesis of aldonitrones

This is the first report on nano semiconductor photocatalytic synthesis of aldonitrones through in situ trapping of hydroxylamine intermediates in the presence of aromatic aldehydes in aqueous media under visible light irradiation. A new highly efficient dispersible CdS nanorod photocatalyst was synthesized. The characterization of the catalyst was done by transmission electron microscopy (TEM), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) analysis, CHNS elemental analysis, thermogravimetric analysis (TGA) and diffuse reflection spectroscopy (DRS). The CdS nanorods have 12-18 nm sizes according to TEM. The catalyst was used successfully in the chemoselective photocatalytic reduction of nitroarenes using a CdS/poly ethyleneglycol 400-water system (CdS/PEG-H2O). The reaction was successfully carried out under green and blue LED illumination by using ammonium formate as a sacrificial electron donor in the presence and absence of an aldehyde, producing aromatic amines or aromatic nitrones respectively. The reusability of the CdS nanorod photocatalyst was tested four times. Moreover, the stability of the catalyst was confirmed by the characterization of a reused catalyst.