Synthesis of a Symmetrical <i>tris</i>-Tetrazole as Isostere of a Tricarboxylic Acid: Behind New Tridentate Ligands for MOFs

Abstract

The synthesis and characterization of three tridentate ligands for new MOFs are described. A triple aminolysis of the 1,3,5-tribenzoyl chloride with p-aminobenzoic acid gave the tricarboxylic acid 3 in 90% yield. Moreover, the same reaction, also from the 1,3,5-tribenzoyl chloride, but using p-aminobenzonitrile gave the new tris-benzonitrile 5 in 85% yield. Finally, this later one was treated with sodium azide and a Lewis acid to synthesize the new tris-tetrazole-based ligand 7 in 72% yield through a [3 + 2] azide-nitrile cycloaddition. It is noteworthy that the isosterism between carboxylic acids and tetrazoles may be considered to design and fabricate new MOFs with similar properties.

Keywords

• metal-organic frameworks (MOFs)
• tridentate ligands
• tricarboxylic acids
• <i>tris</i>-benzonitriles
• <i>tris</i>-tetrazoles
• aminolysis