Facile tuning of strong near-IR absorption wavelengths in manganese(III) phthalocyanines via axial ligand exchange

The facile tuning of near-infrared absorption of manganese(III) phthalocyanines was accomplished by changing the nature and number of bound axial ligands. For a series of axial ligands on manganese α-octabutoxyphthalocyanine and α-octakis-(isopropylthio)phthalocyanine, the electron density on the metal and its displacement from the Pc-ring plane both control the position of the complex's Q-band. For these two macrocycles, this strong absorption band could be tuned over a λmax range of 815–948 nm by axial ligand exchange.