Comparative DFT study of americium and europium complexation with 2,9-bis(1,2-diazin-3-yl)-1,10-phenanthroline ligand in gas phase

•Comparative study of americium and europium complexation with BTPhen-CH was done.•Both pure cation and its tetraaquatrinitrato complex were used as reactants.•Five different reactions were studied.•In case of pure cation europium forms the more stable complexes.•In case of tetraaquatrinitrato complex americium form the more stable complexes.