Heat capacities and thermodynamic properties of a novel mixed-ligands MOFs

Abstract

A novel metal-organic frameworks [Cu-2(OH)(2,2'-bpy)(2)(BTC) center dot A 2H(2)O](n) (CuMOF, BTC = benzene-1,3,5-tricarboxylic acid, 2,2'-bpy = 2,2'-bipyridine) has been synthesized hydrothermally and characterized by single crystal XRD, FT-IR spectra. The low-temperature molar heat capacities were measured by temperature modulated differential scanning calorimetry (TMDSC) for the first time. The thermodynamic parameters such as entropy and enthalpy relative to reference temperature 298.15 K were derived based on the above molar heat capacity data. Moreover, the thermal stability and the decomposition mechanism of CuMOF were investigated by TG-MS (thermogravimetry-mass spectrometer). A four-stage mass loss was observed in the TG curve. MS curve indicated that the gas products for oxidative degradation of CuMOF were H2O, CO2, NO and NO2.