Stoichiometry of metal ligand complex - Lab Report Example

Stoichiometry of metal ligand complex Objective: To determine the correct ligand-to-metal ratio using tissue culture plate and spectrophotometric methods.ProcedureInto each of the five wells (A, B, C, D and E), 3 drops of hydroxylamine were added. 2 drops of 0.02 M Fe(II ) solutions were then added to well A, 4 drops to well B, 6 drops to well C, 8 drops to well D and 10 drops to well E. The reverse order was followed in adding 0.02 M of ferrozine. The above procedure was repeated in the case of phenanthroline and terpyridine ligands.

Results Table 1: Concentrations of Stock SolutionsCompoundConcentration, g/LConcentration, Miron (II)1.0000.020Ferrozine1.0000.002terpyridine0.5000.002phenanthroline1.0000.006Table 2: Data from Spectrophotometric AnalysisFerrozineSolutionVolume of Iron (II) in cuvette, mL[Iron (II)], MVolume Ferrozine in cuvette, mL[Ferrozine], MAbsorbanceA0.2700.1501.3300.00300.4140B0.5300.0751.0700.00370.4100C0.8000.0500.8000.00500.3960D1.0700.0370.5300.00750.4320E1.3300.0300.2700.01500.4160F     TerpyridineSolutionVolume of Iron (II), mL[Iron (II)], MVolume terpyridine, mL[terpyridine], MAbsorbanceA    .

195 B     .290C     .400D     .535E     .516F     PhenanthrolineSolutionVolume of Iron (II) in cuvette, mL[Iron (II)], MVolume phenanthroline in cuvette, mL[phenanthroline], MAbsorbanceA0.2670.0150.1370.09000.0250B0.5330.0751.0670.0110-0.0830C0.8000.0500.8000.01500.0480D1.0670.0370.5330.0230-0.0554E0.1330.0300.2670.04500.0976F     Figure 1: A graph of wells as a function of no. of drops for FerrozineFigure 2: A graph of wells as a function of no. of drops for PhenanthrolineFigure 3: A graph of volume of metal solution versus absorbance for Ferrozine Figure 4: A graph of volume of metal solution versus absorbance for phenathroline DiscussionFrom the concentration of Phenanthroline and iron, moles of Fe in the complex = 0.

00004 while those of Phenanthroline = 0.00008, therefore mole ratio is 1:2 therefore n value is 2. The experimental n value for Phenanthroline in Fe (II) is 2 while that of ferrozine is 3(Amaal et al, 2008). The experimental n values agree with the values predicted by the sructures of the ligand.Works cited Amaal Y. Assaf , Jassim M. Alyass , Abeer S. Mohammed. (2008). Synthesis and characterization of Fe(II), Co(II), Ni(II), Cu(II) and Zn(II)complexes with mixed ligands of α-naphthylamine dithiocarbamate and 1,10-phenanthroline.

Department of Chemistry, College of Education, Mosul University , Mosul , Iraq.