Synthesis and investigations on iron (ii) Schiff base derived from 2-hydroxybenzylaldehyde and l-valine

A Schiff base was prepared from the reaction of 2-hydroxybenzylaldehyde and L-valine as reported. The reaction of the Schiff base with iron (II) chloride gave N – (2 – hydroxybenzyl) - L -α - valine iron (II) complex compound. The Schiff base is a crystalline white, has a yield of 66 percent and amelting point of 225oC. The complex compound is pale brown, has a yield of 62% and decomposition temperature of 278oC. The ligand and its iron (II) complex compound are insoluble in most common solvents but are soluble in ethanol-water mixture. The molar conductance of the complex compound determined is 6.4 ohm cm2 mol-1. The infra-red spectral measurement of the ligand and its iron (II) complex compound showed bands in the range 1510 -1530cm-1, assignable to v(C=N) stretching vibrations. The broad bands in the range 3271 - 3415cm-1 observed in the ligand and iron (II) Schiff base complex are assigned to v(O-H) stretching vibrations. The dissociation constant (pKa) of the Schiff base determined is 8.84. The ratio of the Schiff base to the iron (II) ion in the complex determined using pH measurements is 1:1