Solvent-Controlled Photoinduced Processes in a bis(acridinium-Zn(II) porphyrin)-tetra(4-pyridyl) porphyrin host-guest complex

Metalloporphyrins, known for their rich photophysical and electrochemical properties, are widely studied as coordinating sites in supramolecular receptors.[1] Notably, porphyrin-N-acridinium conjugates exhibit ultrafast electron transfer (eT) from the porphyrin donor to the acridinium acceptor, which quenches fluorescence in both units. Among these, a bis(acridinium-porphyrin) tweezer (Figure 1) stands out as a multi-responsive array with Zn(II) porphyrin coordination sites and acridinium switching units.[2-3] Here, we explore its complexation with meso-(5,10,15,20-tetra(4-pyridyl)porphyrin (TPyP) in two different solvents (CH2Cl2 and toluene) and discuss the photophysical behavior of the formed complex. Interestingly, the solvent polarity strongly affects the photophysical response of the system. References: [1] V. Valderrey, G. Aragay, P. Ballester Coord. Chem. Rev. 2014, 258-259, 137-156. [2] A. Edo-Osagie, D Sanchez-Resa, D. Serillon, E. Bandini, C. Gourlaouen, H. P. Jacquot de Rouville, B. Ventura, V. Heitz, Cr. Chim. 2021, 24, 47-55; [3] A. Edo-Osagie, D. Serillon, F. Ruani, X. Barril, C. Gourlaouen, N. Armaroli, B. Ventura, H.-P. Jacquot de Rouville, V. Heitz, J. Am. Chem. Soc. 2023, 145, 10691−10699.