[Eu(ABA)(phen)(2)(H2O)(3)](ClO4)(3).3phen-4.5H(2)O (1) and [Eu(Val)(phen)(2)(H2O)(3)](ClO4)(3).3phen.2H(2)O (2) are two new europium. complexes with amino acids and 1,10-phenanthroline (phen = 1,10-phenanthroline, ABA = alpha-amino butyl acid, Val = L-valine). Their crystal structures were measured by X-ray crystallography. Europium. atoms in both complexes are nine-coordinated with bidentate 1,10-phenanthroline and carboxylate anion of amino acids, and water molecules. In the solid state, 1 and 2 have a structure involving aromatic stacking of the coordinated and non-coordinated 1,10-phenanthroline and the oxygen atoms of non-coordinated perchlorate anions being H-bond acceptors connect [Eu(ABA)(phen)(2)(H2O)(3)](3+).3phen-4.5H(2)O or [Eu(Val)(phen)(2)(H2O)(3)](3+).3phen.2H(2)O in their structures. In their interactions, several C-H...O bonds play an important role. Owing to their different amino acid ligands and the number of lattice water molecules, there is some difference in their hydrogen bond patterns in 1 and 2. The side chain of L-valine is involved in the formation of C-H...O bonds. Hydrogen bond and pi-pi interactions determine the supramolecular formation of three-dimensional net works of both complexes. (C) 2002 Elsevier Science B.V. All rights reserved.