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)]center dot DMF}(n) (1 and 2), where 34pba is 3-(4-pyridy1)benzoate, were prepared by solvothermal methods. 1 is a three-dimensional metal organic framework formed by linking [Co-2(34pba)(8)] clusters in a bcu net. 2 consists of single [Co(34pba)(4)] units in a tetragonal plane net of sql topology. The thermal conditions leading to their selective synthesis were established: 120 degrees C for 1 and 75 degrees C for 2. 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 1 and 49(3)-58(3) kJ mol(-1) for 2. For 1, 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.