Complexes of Iron Cations with N-Phenylglycinate or Oxalic Acid

N-phenyglycine plays a very important role in obtaining adhesion of restorative composites to dentin and enamel (Bowen et al., 1982a). In a systematic investigation, ferric or ferrous N-phenylglycinate complexes formed when aqueous ferric nitrate or ferrous chloride was combined with solutions of potassium N-phenylglycinate in stoichiometric proportions. The molal ratios of iron ion to N-phenylglycinate ion in each complex were confirmed by osmolality measurements with a freezing-point osmometer. The reaction of aqueous solutions of oxalic acid with ferric nitrate indicated formation of ferric oxalate complexes with a stoichiometry of Fe2(oxalate)3 in solution, using Job's method of continuous variations (1925;1928).