Microwave assisted synthesis of a new lead(ii) porous three-dimensional coordination polymer: study of nanostructured size effect on high iodide adsorption affinity

Abstract

A three-dimensional (3D) porous coordination polymer, [Pb(4-bpdh)(NO₃)(H₂O)]_n (HMTI-1), has been synthesized under microwave-irradiation (MW) of identical reaction mixtures of Pb(II) salt and 2,5-bis(4-pyridyl)-3,4-diaza-2,4-hexadiene (4-bpdh) at different powers. The microwave synthesis of HMTI-1 has been compared to its conventional synthesis. It has been found that by using MW synthesis HMTI-1 can be obtained in a much shorter synthesis time with improved yield and physical properties. Compound HMTI-1 is stable up to 300 °C in the static atmosphere of nitrogen and useful for loading and unloading of guests. In this compound, we successfully loaded the porous crystals and nano-HMTI-1 with I₂ by suspending them in a solution of I₂ in cyclohexane. The delivery of I₂ from HMTI-1⊃3I₂ performed in ethanol, a nonaromatic solvent, at room temperature was determined by UV/vis spectroscopy. A comparison of adsorption and desorption rates of iodide between nano and bulk compounds was also conducted.