Iron(tetraphenylporphyrinato) chloride
# Iron(tetraphenylporphyrinato) chloride

Iron(tetraporphyriinato) chloride is the coordination complex with the formula Fe(TPP)Cl where TPP is the dianion $[C_{44}H_{28}N_4]^{2-}.$ The compound forms blue microcrystals that dissolve in chlorinated solvent to give brown solutions. In terms of structure, the complex is five-coordinate with idealized $C_{4v}$ point group symmetry. It is one of more common transition metal porphyrin complexes.

## Synthesis and reactions

Fe(TPP)Cl is prepared by the reaction of tetraphenylporphyrin $(H_2TPP)$ and ferrous chloride in the presence of air:

    $H_2TPP$ + $FeCl_2$ + 1/4 $O_2$ → Fe(TPP)Cl + HCl + 1/2 $H_2O$

The chloride can be replaced with other halides and pseudohalides. Base gives the "mu-oxo dimer":

    2 Fe(TPP)Cl + 2 NaOH → $[Fe(TPP)]_2O$ + 2 NaCl + $H_2O$

Most relevant to catalysis, the complex is easily reduced to give ferrous derivatives (L = pyridine, imidazole):

    Fe(TPP)Cl + e- + 2 L → $Fe(TPP)L_2$ + $Cl^−$

The complex is widely studied as a catalyst.

