Synthesis, excitation energy transfer and singlet oxygen photogeneration of covalently linked N-confused porphyrin–porphyrin and Zn(II) porphyrin dyads

Dyads of a N-confused porphyrin (NCP) moiety covalently linked to a porphyrin free-base (H2P) or a zinc(II) porphyrinate (ZnP) moiety via a flexible alkyl chain of variable length have been synthesized. Photoluminescence study demonstrated an efficient excitation energy transfer from H2P/ZnP moiety to the NCP moiety. Measurement of the near-IR emission of singlet oxygen produced by these dyads via photosensitization showed that the NCP–ZnP dyads (ФΔ = (0.61–0.65) ± 0.13) were better 1O2 generators than the NCP–P dyads (ФΔ = (0.36–0.41) ± 0.08).