Recent theoretical and experimental research has shown that iron coordination complexes exhibit attractive properties for many applications. One important application for these types of complexes is dye sensitization, which involves charge transfer processes. Such complexes can be designed to exhibit enhanced properties. The dihydroxobis (1,10-phenanthroline) iron (I) complex may be synthesized by reacting 1,10 phenanthroline with sodium hexahydroxoferrate (III) under appropriate conditions in a 2:1 ratio respectively.

(a) Using your knowledge of coordination chemistry:

(i) Write the formula for dihydroxobis (1,10-phenanthroline) iron (II).

(i) Suggest two possible types of isomerism that the dihydroxobis (1, 10-phenanthroline) iron (II) complex may display and draw the appropriate structures.

(iii) State whether 1,10-phenanthroline is a weak or strong field ligand, clearly indicate the resultant spin state and the coordination geometry of iron. Illustrate the electronic configuration for the central ion using a completely labelled crystal field splitting energy diagram and calculate the crystal field stabilization energy (CFSE) for iron in the dihydroxobis (1,10-phenanthroline)iron(II) complex.

(iv) Evaluate the magnetic

dipole moment and suggest how the dihydroxobis (1,10-phenanthroline)iron(I) complex will respond to a magnetic field.

(b) The two 1,10-phenanthroline ligands may be replaced by two water molecules (H2O) to give the diaquadihydroxoiron(II) complex.

(i) Deduce the possible geometric arrangement/s for the diaquadihydroxoiron (Il) complex and

draw the relevant structures.

(ii) Using a completely labelled crystal field splitting energy diagram, show the electronic configuration for any one of the geometries you stated in (i).