AXIAL LIGAND EXCHANGE REACTIONS OF FERROUS PHTHALOCYANINE . EXCHANGE OF IMIDAZOLE FOR DIMETHYL SULFOXIDE

Ferrous phthalocyanine dissolves in dimethyl sulfoxide to give a diamagnetic blue solution. The rate of exchange of imidazole (Imid) for dimethyl sulfoxide at the axial sites to give green FePc(Imid)2 obeys the rate law [formula omitted] At 25° ΔH≠ = 17.3 kcal/mole and ΔS≠ = 1.8 eu. Replacement of coordinated dimethyl sulfoxide by the first imidazole molecule is rate determining and exerts a powerful trans effect on the exchange of the second dimethyl sulfoxide ligand. © 1969, American Chemical Society. All rights reserved.