Low-temperature molar heat capacity and thermodynamic properties of rare earth complex

Abstract

A heptanuclear trigonal prismatic polyhedron, [EuCu6(μ-OH)3(Gly)6Im6](ClO4)6·3H2O, was synthesized and characterized by elemental analysis and X-ray single-crystal diffraction. The complex crystallize is the rhombohedral R3 space group (a = b = 15.8673 A, c = 23.4038 A, V = 5103.0(6) A3, Z = 3). In the clusters, Eu3+ ions are situated in the center of a prism formed by six copper atoms and coordinate to nine oxygen atoms with a tricapped trigonal prismatic coordination polyhedron. Six glycinato ligands and six imidazole terminal ligands (each coordinates to one Cu2+) were used in the construction of the cluster. The low-temperature molar heat capacity, C p,m, and thermodynamic properties of the complex were studied with an adiabatic calorimeter from 80 to 370 K. The thermodynamic functions [H T–H 298.15] and [S T–S 298.15] were derived in the temperature range from 80 to 370 K with a temperature interval of 5 K. The thermal properties of the complex from 300 to 800 K were studied by DSC and TG in nitrogen atmosphere.