Joining chromophores: A porphyrin-BPI fused system

A diminoisoindoline-tetraphenylporphyrin (as Zn complex) unit has been used as building block for the preparation of a tetraphenylporphyrin-1,3-bis(2-pyridylimino)isoindo-line conjugate (3). The chelating system of this molecule possesses two different binding centers. The optimization of the synthetic procedure allowed to obtain the ZnTPP-BPI moiety in very good yields, the structure of which was identified by means of UV/Vis, NMR, mass and X-ray methods. The Zn-porphyrin complex was then subject to Zn ion removal from the porphyrin core, allowing the isolation of the corresponding free base derivative. The optical features of the compound are very interesting, as expected from the fusion of two chromophores active in the UV and visible regions of the optical spectrum; this has also been confirmed by testing ZnTPP-BPI (3) as chemo-sensor for metal cations detection. © 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim