Effect of non-peripheral alkyloxy substituents on the structure and spectroscopic properties of metal-free phthalocyanines

Four non-peripheral alkyloxy substituted metal-free phthalocyanines have been synthesized and characterized with X-ray crystal structure, IR, UV–vis and 1H NMR. It is found that the center caves of Pc skeletons were expanded but their ring currents were reduced by the introduction of alkyloxy substituents on the non-peripheral positions.