title: Copper(II) and nickel(II) ternary complexes of L-dopa and related compounds.
abstract: The stability constants of the mixed ligand complexes of L-dopa, L-tyrosine, L-phenylalanine, and dopamine with copper(II) and nickel(II) ions and with 2,2'-bipyridyl and 1,10-phenanthroline were determined pH-metrically at 25 degrees C and an ionic strength of 0.2 mol/dm3 (KCl). Spectral studies were made to establish the binding mode of the ambidentate L-dopa in the ternary complexes. In contrast with the aromatic (N,N) donor atoms, the (O,O) binding mode of L-dopa is particularly favored in its ternary systems with copper(II) and nickel(II); thus, even at physiological pH there is a very considerable formation of (O,O)-bound mixed ligand complexes containing a free amino acid side-chain. Numerous binary transition metal-L-dopa complexes and the ternary complexes formed with various B ligands have been evaluated from a coordination chemistry aspect, with regard to the possibility of their therapeutic application in the treatment of Parkinson disease.
mesh_terms: D055598:Chemical Phenomena; D002621:Chemistry; D003300:Copper; D004298:Dopamine; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D007980:Levodopa; D008024:Ligands; D009532:Nickel; D009994:Osmolar Concentration; D010649:Phenylalanine; D013329:Structure-Activity Relationship; D014443:Tyrosine
chemical_list: D008024:Ligands; D014443:Tyrosine; D007980:Levodopa; D010649:Phenylalanine; D003300:Copper; D009532:Nickel; D004298:Dopamine