Theoretical investigation using AMYR calculations of five quinoxalinones in interaction with water molecules

Program amyr,originally written by s. fraga (university of alberta,canada),allows for the calculation of molecular associations using a pair-wise atom-atom potential. the interaction energy is evaluated through a 1/r expansion. our improved version includes a dispersion energy term in the potential corrected by damping functions,the possibility of carrying out energy minimizations through variable metric methods,as well as the optional calculation of geometrical and topological indices. program amyr has been adapted also for high-performance computing and vectorization. an interactive version of the program carries out real-time molecular graphics showing simultaneously the energy profile of the calculations. in this paper,amyr model is used for the first time in calculation of five quinoxalinones [quinoxalin-2(1h)-one (c8h6n2o),6-chloroquinoxalin-2(1h)-one (c8h5n2ocl),6-bromoquinoxalin-2(1h)-one (c8h5n2obr),6-méthylquinoxalin- 2(1h)-one (c9h8n2o) and 6-nitroquinoxalin-2(1h)-one (c8h5n3o3)] molecules interacting with water molecules. intermolecular interaction energies have been obtained and the stable conformation was determined in each case. changes of conformation were considered for the c-n-c angle a when the solute molecules were surrounded by n water molecules.