Investigations into the Electrochromism of Lutetium and Ytterbium Diphthalocyanines

A comparison was made between the infrared, electronic, and electron spin resonance spectroscopic properties of lutetium and ytterbium diphthalocyanines, in the solid state as analytically pure powders, and after vacuum sublimation as thin deposited films. No significant differences were observed. Spectroscopic analysis of the sublimed films during electrochromic changes showed that the lutetium and ytterbium complexes behaved in a similar manner. Both gave identical variations in their electronic spectra with potential. Electron spin resonance data demonstrated that the oxidative color change is not associated with a change in paramagnetism, although the shape of the signal from the lutetium complex was altered upon oxidation. The ytterbium complex displayed no ESR signal before or after electro‐oxidation.