Preparation and characterization of 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin grafted on organosilane-pillared montmorillonite by covalent bonding

Montmorillonite (MMT)-based composites are usually prepared by the absorption method, which results in the unstable MMT composites, because adsorbates are easy to drop down from MMT. In this work, 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin (H 2 TCPP) molecules were grafted on interfaces of (3-aminopropyl)triethoxysilane (APTES)-pillared MMT by dehydration condensation reaction. X-ray diffraction (XRD) revealed that the interlayer space of the MMT was enlarged from 16.24 to 22.21 Å by introduction of APTES. Fourier-transform infrared (FT-IR) data verified the covalent bonding between APTES-pillared MMT and H 2 TCPP molecules. UV-Vis absorption spectra displayed that the Soret band of H 2 TCPP molecules in H 2 TCPP/APTES/MMT composites had a red-shift with 17 nm compared with that of the monomers, revealing that H 2 TCPP molecules assembled into J-aggregates. Moreover, H 2 TCPP/APTES/MMT composites were characterized by thermogravimetric analysis (TGA) and fluorescent spectrophotometer. The APTES-pillared MMT modified with porphyrin has a potential application in biomedicine and environment. 5,10,15,20-Tetrakis(4-carboxyphenyl)porphyrin (H 2 TCPP) molecules were grafted on interfaces of (3-aminopropyl)triethoxysilane (APTES)-pillared MMT by dehydration condensation reaction.