Adduct formation of aromatic biomolecules with Pt(II)-aromatic diimine-polyaminopolycarboxylate complexes

Non-covalent interactions such as electrostatic interactions, hydrogenbonds and aromatic ring stacking interactions play important roles in biological systems for molecular recognition. Metal-coordinatedaromatic diimine ligands such as 1,10-phenanthroline (phen) interact to aromatic moieties with stacking interactions asseen in [CuII(phen)(Trp)] (Trp = tryptophan), and interactions with uncoordinated aromatic molecules lead to formation of adducts [1–3].We studied syntheses and characterizations of binuclear complexes of PtII(phen) moieties bound to EDTA and its analogs.[PtCl2(phen)] reacted with EDTA, 1,3-diaminopropane-N,N,N’,N’-tetraacetate (PDTA), and 1,4-diaminobutane-N,N,N’,N’-tetraacetate(BDTA) to form [Pt2(phen)2(EDTA)] (1), [Pt2(phen)2(PDTA)] (2),and [Pt2(phen)2(BDTA)] (3), respectively, where the Pt(phen) units are bound to the both ends of EDTA, etc. with a 3N1O donor set, asrevealed by X-ray crystal structure analyses. Adduct formations of the complexes with aromatic biomolecules such as indoleacetate and5-hydroxytryptamine (serotonin) were studied by 1H NMR measurements and calorimetry methods. Financial support by the Kansai University is gratefully acknowledged. References1. Yamauchi O, Odani A, Hirota S (2001) Bull Chem Soc Jpn 74:1525–1545.2. Yamauchi O, Odani A, Takani M (2002) J Chem Soc Dalton Trans 3411–3421.3. Yajima T, Maccarrone G, Takani M, Contino A, Arena G, Takamido R, Hanaki, M, Funahashi Y, Odani A, Yamauchi O (2003)Chem Eur J 9:3341–3352.