Electron spin resonance spectrum of copper-63 phthalocyanin. A reassessment of the bonding parameters

Abstract

The e.s.r. spectrum of isotopically pure powdered copper-63 phthalocyanin magnetically dilute in metal-free phthalocyanin has been measured. Much improved resolution of the hyperfine spectrum has allowed more accurate measurement of the nitrogen hyperfine tensor. The bonding parameters β₁ ² and β₂ ² are found to be 0·75 and 1 respectively, whilst ε² is estimated as 9·51 or 0·60. Much of the earlier work is found to be in error, particularly in the analysis of the spectrum. A line-width alternation effect is detected and accounted for in terms of the anisotropy of the nitrogen hyperfine tensor.