Thermal stability and radiation damage in the phthalocyanines

Abstract

The phthalocyanine (pc) complexes of a number of metals have been prepared. The e.p.r. spectra of the paramagnetic pc complexes (VO²⁺, Cr²⁺, Mn²⁺, Co²⁺, Cu²⁺, Mo²⁺) show metal ion resonances, while those of the diamagnetic pc complexes (H₂²⁺, Na₂²⁺, Mg²⁺, Ni²⁺, Zn²⁺, Pd²⁺, Cd²⁺, Sn²⁺, Pt²⁺ and Pb²⁺) generally give free spin resonances with g ≈ 2.003 and line widths less than 1 mT. The preparative conditions have been shown to affect the free spin concentration in H₂(pc). Irradiation also affects the e.p.r. signal intensity in H₂(pc), Zn(pc) and Ni(pc), and there are also changes in the near-infrared spectra of most pc complexes. The results are due to the presence of two types of defect, the first arising from decomposition during crystal growth and the second arising from a possible local disorder in the crystals which is produced by γ-irradiation. The latter may be due to a cross-linking of adjacent pc molecules. Oxygen absorption does not seem to be the major factor in the origin of the free spin resonances.