Synthesis and Catalytic Application of MTsCOO-Cu as a Melamine-Based Metal-Organic Framework in Facile Preparation of the 5-Substituted-1H-Tetrazoles

A novel melamine-based metal-organic framework (MTsCOO-Cu) has been designed, synthesized, and structurally characterized by FT-IR, NMR, PXRD, FE-SEM, EDX mapping, DTA, and TGA techniques. The MTsCOO-Cu is successfully synthesized by the reaction of melamine with tosyl chloride and oxidation of methyl groups of the tosyl counterpart to carboxylic acids moieties and a consequent reaction with copper ion under ultrasonic irradiation. The synthesized MTsCOO-Cu is catalytically used for the facile preparation of a series of 5-substituted-1H-tetrazoles derivatives via click [3+2] cycloaddition reactions between various arrays of aromatic and aliphatic nitriles and sodium azide in PEG-400 at 75 degrees C up to 86 %. The crucial reaction parameters including the type of solvent, temperature, and catalyst loading in progressing the reaction are evaluated and discussed. The synthesized MTsCOO-Cu MOF showed an excellent catalytic activity, high chemical and thermal stabilities above 600 degrees C, simple preparation with readily available starting materials, and also ease of recyclability and reusability for four consecutive uses without considerable loss of activity. The output of this work may open new approaches for using new generations of MOFs catalysts in diverse chemical transformations.