“…(2007). E63, m1514 (4-Oxo-4H-pyrindin-1-yl)acetic acid (4-OPA -), an important medical intermediate (Edwards et al, 1977), is a potential multidentate ligand with versatile binding ability. Recent studies in our laboratory have demontrated that the complexes containing 4-OPAligands exhibit two type structures: mononuclear in which the 4-OPAligands exist as counter anions (Gao et al, 2004;Zhang et al, 2004a,b;Zhao et al, 2004;Zhang et al, 2005) and polymer with the adjacent metal ions bridged by carbonyl and carboxylate groups of 4-OPAligand (Zhang et al, 2006).…”