Phthalocyanines Containing Silicons in Their Peripheral Substituent Groups

Some phthalonitriles and 1H-isoindole-1,3(2H)-diimines containing silicon(s) in their alkoxy substituent groups are prepared and used for phthalocyanine formation reactions. Silicon-carbon bonds often survive under the reaction conditions using K₂CO₃ in N,N-dimethylformamide (DMF), but are often broken in the presence of sodium hydride. Silicons in the alkoxy groups do not affect the electronic absorption spectra of phthalocyanines in solution significantly. The Q band of films of phthalocyanines (Pcs) with alkyl or alkoxy groups attached to benzene carbons furthest from the Pc core lies to the blue compared to the Pcs in solution, while films of Pcs with eight alkoxy groups closest to Pc core have a Q band shifted to the red.