Ni(II) complex immobilized on Fe3O4 was used for the synthesis of 5-substituted 1H-tetrazoles via [3+2] cycloaddition reactions of various organic nitriles with sodium azide in PEG as solvent (green solvent). Nanocatalyst can be easily recovered by an external magnetic field and reused for subsequent run for at least 8 times with less deterioration in catalytic activity.
