Details

Autor(en) / Beteiligte

• Zanetti-Polzi, Laura
• Amadei, Andrea
• Djemili, Ryan
• Durot, Stéphanie
• Schoepff, Laetitia
• Heitz, Valérie
• Ventura, Barbara
• Daidone, Isabella

Titel

Interpretation of Experimental Soret Bands of Porphyrins in Flexible Covalent Cages and in Their Related Ag(I) Fixed Complexes

Ist Teil von

• Journal of physical chemistry. C, 2019-05, Vol.123 (20), p.13094-13103

Ort / Verlag

American Chemical Society

Erscheinungsjahr

2019

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• The essential features of the experimental Soret bands of two covalent cages, consisting of two zinc-porphyrins connected by four flexible spacers, are for the first time interpreted and characterized at a molecular level by means of a mixed quantum/classical procedure based on molecular dynamics (MD) simulation and the perturbed matrix method (PMM). The same method allows also for a comprehensive interpretation of the changes in the UV–visible absorbance of the cages upon silver­(I) complexation to the peripheral binding sites. Although the zinc-to-zinc distance is found to be similar in both cages, the MD-PMM calculations show that the conformation adopted by the cage with longer linkers corresponds to more slipped porphyrins, giving rise to a red-shifted (7–8 nm), broader, and slightly split Soret peak with respect to the cage with shorter linkers. The process of silver­(I) complexation separates the two porphyrins in a face-to-face conformation in both cages, resulting in narrower (and more similar) Soret bands due to a reduced excitonic coupling. Despite the similar features of the spectra of the two silver­(I)-complexed cages, a slight difference in the peak maxima of about 2 nm is observed, arising from a slightly shorter zinc-to-zinc distance in the cage with longer linkers. These results show that the MD-PMM methodology is a reliable method to obtain information on the relative disposition and exciton coupling interaction of porphyrins in flexible systems in solution, from the analysis of their absorption spectra.