Pb(II)-MOFs assembled with tetrazole-based carboxylic acids as a burn rate modifier

Three tetrazole-based carboxylic acids, 3,3-di(1H-tetrazol-5-yl)pentanedioic acid (H4L1), 2-(5-pyridin-4-yl-tetrazol-2-yl)propionic anion (HL2), and 5-(2-pyridyl)tetrazole-2-acetic acid (HL3), were selected as ligands to synthesize three new Pb(II)-coordination polymers, [Pb-2(L-1)] <middle dot> H2O (1), [Pb(L-2)(NO3-)] (2), and [Pb(L-3)(2)(H2O)] <middle dot> H2O (3). These metal-organic frameworks have been characterized by elemental analysis, FT-IR, and single crystal X-ray diffraction. The results demonstrated that 1 displayed a 3-D network, while 2 and 3 show 2-D framework and 1-D chain, respectively. The differential scanning calorimetry and thermogravimetric analyses gave thermodynamic parameters (Delta H, Delta S, and Delta G). The results showed that 1-3 may be promising high-energy materials.