  The thermodynamic properties of a spatially anisotropic spin-1/2 Heisenberg
model for a Cu$_5$ pentameric molecule is studied through exact
diagonalization. The elementary geometry of the finite lattice is defined on
nanomolecules consisting of an hourglass structure of two corner-sharing
scalene triangles which are related by inversion symmetry. This microscopic
magnetic model is quite suitable to describe the molecular nanomagnetic
compound Cu5-NIPA. The ground-state phase diagram, as well as the corresponding
total magnetization, are obtained as a function of the anisotropic exchange
interactions and the external magnetic field. The thermodynamic behavior of the
model at finite temperatures is also studied and the corresponding
magnetocaloric effects are analyzed for various values of the Hamiltonian
parameters.
