In this exploration, new recyclable mesoporous-supported iron particles with the ligand and without ligand (MCM-41@ 3,4,5-tri hydroxyphenyl acetic acid @Fe and MCM-41@Fe) have been developed through post- functionalization modification of silica MCM-41. These catalysts were demonstrated to be novel, effective, and green for the synthesis of 5-substituted 1H-tetrazoles from aryl nitriles in water. In these systems, 5-substituted 1H-tetrazoles are produced as the only product. Fe3+species were identified as active sites. The ordered mesoporous iron-silica catalyst with the ligand displayed better catalytic activity compared to iron-silica catalyst without the ligand, which was ascribed to the improvement of the inter-action of iron with the support. The catalysts can be easily separated using simple recovery and reused several times with consistent activity.
