Effect of peripheral substitution on spectral and catalytic properties of copper phthalocyanine complexes

Abstract

The effect of peripheral substitution on the spectral and catalytic properties of copper phthalocyanine complexes has been investigated. The complexes were characterized by elemental analysis, FT-IR, UV-VIS and electron paramagnetic resonance (EPR) techniques. The EPR spectra of solid samples were broad due to intermolecular spin-spin interactions while the frozen H₂SO₄ solutions showed well resolved hyperfine and superhyperfine features due to copper and nitrogen nuclei, respectively. The unpaired electron occupies a 3d_x²-y² orbital of copper(II). The ground state molecular orbital coefficients were estimated from the spin Hamiltonian parameters. The activity for epoxidation of styrene was more for complexes with electronegative substituents. The enhanced activity of substituted CuPc complexes has been correlated to the electronic and molecular structure parameters.