Metal ion interactions with nucleic acid bases in the tripodal tris(2-aminoethyl)amine (tren) ligand-system: Crystal structures of [Ni(tren)(adeninato)(ClO4)] · adenine, [Cu(tren)(9-ethylguanine)] · (ClO4)2, [{Ni(tren)(H2O)}2(hypoxanthinato)] · (

Treatment of tris(2-aminoethyl)amine (tren) and Cu(ClO4)2, Ni(ClO4)2, or Ni(NO3)2 with adenine, 9-ethylguanine, or hypoxanthine gave five ternary tren-metal ion-nucleobase complexes and their crystal structures have been determined by X-ray diffraction. The tren-capped metal ion binds to N(7) of guanine derivatives but not to N(7) of adenine. The importance of interligand interactions that affect metal binding sites on nucleobases is reemphasized.