Enthalpies of sublimation and crystal lattice energies of 9-acridinamine and its derivatives

Enthalpies of sublimation of acridine, 9-acridinamine, N-methyl-9-acridinam ine, 10-methyl-9-acridinimine, N,N-dimethyl-9-acridinamine and N-methyl-10- methyl-9-acridinimine were determined by fitting to thermogravimetric curve s with the Clausius-Clapeyron relationship. These values compare well with crystal lattice energies predicted theoretically as the sum of electrostati c, dispersive and repulsive interactions. Partial charges for these calcula tions were obtained on an ab initio level, while atomic parameters were tak en from literature.