Metal phthalocyanine showing four-peak Q-band similar to metal-free phthalocyanines: Nickel 1,4-di(trifluorosulfonyl)-phthalocyanine

Nickel phthalocyanines (NiPc) substituted by trifluorosulfonyl or trimethylsilylethynyl groups have been prepared and characterized using NMR and electronic absorption spectroscopy. In particular, when trifluorosulfonyl groups are introduced to two, so-called, α-benzo positions of one benzene ring of the Pc skeleton, the Q-band splits similarly to the Q-bands of metal-free phthalocyanines. The splitting width of the Q-bands can be interpreted as due mainly to splitting of the LUMOs by the substituents, although splitting between the HOMO-1 and HOMO-2 is also effective to a lesser extent.