Concomitant Metal Organic Frameworks of Cobalt(II) and 3‑(4-Pyridyl)benzoate: Optimized Synthetic Conditions of Solvatochromic and Thermochromic Systems

Two coordination networks, {[Co­(34pba)₂]·DMF}_<i>n</i> (<b>1</b> and <b>2</b>), where 34pba is 3-(4-pyridyl)­benzoate, were prepared by solvothermal methods. <b>1</b> is a three-dimensional metal organic framework formed by linking [Co₂(34pba)₈] clusters in a <b>bcu</b> net. <b>2</b> consists of single [Co­(34pba)₄] units in a tetragonal plane net of <b>sql</b> topology. The thermal conditions leading to their selective synthesis were established: 120 °C for <b>1</b> and 75 °C for <b>2</b>. Their structures were solved and their thermal behavior was investigated. Further experiments established the activation energy for the desorption of the DMF molecules entrapped in their framework: 76(6)–106(16) kJ mol^–1 for <b>1</b> and 49(3)–58(3) kJ mol^–1 for <b>2</b>. For <b>1</b>, sorption experiments were carried out to demonstrate the ability of the coordination network to absorb different solvents, and the framework solvatochromic response was also ascertained