Axially coordinated tin porphyrins anchored graphene oxide hybrid composites as productive catalyst for catalytic conversion of 4-nitrophenol to 4-aminophenol

Axially ligated tin porphyrins were synthesized by proceeding through the preparation of free base and metal incorporated porphyrins. Axially ligated tin porphyrins were anchored with graphene oxide via amide linkage among the carboxylic functional moieties of graphene oxide (GO) and an amino group of axial ligand (4-amino salicylic acid) coordinated to tin porphyrins. 1 H NMR spectroscopy was used to detect the successful formation of free-base porphyrins and their corresponding metal-linked and axially ligated tin porphyrins. In order to probe the interactions between GO and tin porphyrins, the nanohybrids were carefully characterized by using various analytical techniques like Powder X-Ray diffraction (P-XRD), Fourier transform infrared (FT-IR), UV–Visible spectroscopy (UV-Vis) and Fluorescence spectroscopy. These hybrid composites were also characterized by Powder-XRD analysis. The Ground-state absorption and steady-state luminescence measurement illustrated the presence of significant covalent interactions along with effective photoelectrons and excited energy exchange between the tin porphyrin and GO structure. The catalytic activity of resulting hybrids (GO-Sn-Porph 1) and (GO-Sn-Porph 2) were carefully investigated by using a UV-visible Spectrophotometer manifesting the effective reduction of 4-nitrophenol into 4-aminophenol. The mechanism for the catalytic activity of the synthesized nanocatalysts has been discussed. Graphical abstract Herein, axially ligated tin porphyrins anchored with graphene oxide hybrid composites were synthesized and further utilized as versatile catalyst for converting toxic 4-nitrophenol to less toxic 4-aminophenol.