Synthesis and photophysical properties phthalocyanine–pyrene dyads

Metal-free, zinc (II) and nickel(II) phthalocyanines (3–5) with a 1-pyrenylmethoxy substituent on each benzo group were prepared from 4-(1-pyrenylmethoxy)phthalonitrile (2). The new compounds have been characterized by elemental analyses, IR, UV/vis, mass and 1H NMR spectroscopy. The electronic spectra exhibit an intense π–π∗ transition of pyrene unit identity together with characteristic Q and B bands of the phthalocyanine core. The energy transfer to phthalocyanine core and radiative decays of the pyrene emission and phthalocyanine core were examined. Energy transfer through methoxy bridges has been confirmed by ultraviolet irradiation of pyrene antenna leading to red light emission in 3 and 4.

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► New phthalocyanine–pyrene dyads were prepared and characterized.
► The energy transfer from pyrenes to phthalocyanine core was examined.
► Pyrenes are shown to act as efficient photon-harvesting antennas.
► Quantum yield of these systems were calculated.