Synthesis of framework isomer MOFs containing zinc and 4-tetrazolyl benzenecarboxylic acid via a structure directing solvothermal approach

Abstract

The solvothermal synthesis of framework isomers was carried out using the hybrid carboxylate and tetrazolate functional ligand, 4-tetrazolyl benzenecarboxylic acid (H 2 TBC, TBC = 4-tetrazolyl benzenecarboxylate) and zinc. H 2 TBC was also synthesized with the solvothermal approach, and is referred herein as structure 1. Using single-crystal X-ray diffraction, we found that the tetrazolate groups of TBC show an unusual “opposite-on” coordination mode with zinc. Three previously characterized metal-organic frameworks (MOFs) were obtained by systematically changing the solvents of the H 2 TBC-Zn reaction, (1) ZnTBC, 2, which has a non-porous structure; (2) Zn 2 (TBC) 2 (H 2 O), 3, which has an amphiphilic pore structure and (3) Zn 2 (TBC) 2 {guest}, 4, which is porous and has channels containing uncoordinated N heteroatoms. Fluorescence spectra of 4 reveal a strong blue emission mainly from the TBC ligands.