Synthesis, structure, and thermodynamics of a lanthanide coordination compound incorporating 5-nitroisophthalic acid

Highlights: ► A microporous LnMOF have been prepared and characterized. ► The standard molar enthalpy for the compound was determined to be to be −(831.4 ± 16.0) kJ · mol−1. ► Thermodynamics and kinetics of the reaction of formation of the compound were invesitigated. - Abstract: A lanthanide coordination compound, [Sm3(5-nip)4(5-Hnip)(H2O)7·9H2O]n (5-H2nip = 5-nitroisophthalic acid), has been synthesized and characterized by elemental analysis, IR, TG-DSC, and single-crystal X-ray diffraction. Structural analysis reveals that the compound features two kinds of 1D channels with guest water molecules. TG-DSC curves show that the dehydrated product of the compound exhibits high stability up to 673 K. The enthalpy change of reaction of formation in water, ΔrHmθ(l), was determined to be (27.608 ± 0.133) kJ · mol−1 at (298.15 ± 0.01) K by microcalorimetry. Based on a designed thermochemical cycle and other auxiliary thermodynamic data, the enthalpy change of reaction of formation in solid at (298.15 ± 0.01) K and the standard molar enthalpy for the compound, ΔrHmθ(s) and ΔfHmθ, were calculated to be (96.8 ± 0.8) kJ · mol−1 and (−831.4 ± 16.0) kJ · mol−1, respectively. In addition, thermodynamics and thermokinetics of the reaction of formation of the compound were investigated in water.