title: Can Expanded Bacteriochlorins Act as Photosensitizers in Photodynamic Therapy? Good News from Density Functional Theory Computations.
abstract: The main photophysical properties of a series of expanded bacteriochlorins, recently synthetized, have been investigated by means of DFT and TD-DFT methods. Absorption spectra computed with different exchange-correlation functionals, B3LYP, M06 and ωB97XD, have been compared with the experimental ones. In good agreement, all the considered systems show a maximum absorption wavelength that falls in the therapeutic window (600-800 nm). The obtained singlet-triplet energy gaps are large enough to ensure the production of cytotoxic singlet molecular oxygen. The computed spin-orbit matrix elements suggest a good probability of intersystem spin-crossing between singlet and triplet excited states, since they result to be higher than those computed for 5,10,15,20-tetrakis-(m-hydroxyphenyl)chlorin (Foscan©) already used in the photodynamic therapy (PDT) protocol. Because of the investigated properties, these expanded bacteriochlorins can be proposed as PDT agents.
authors.affiliation: Dipartimento di Chimica e Tecnologie Chimiche, Università della Calabria, I-87036 Arcavacata di Rende, Italy. gloria.mazzone@unical.it.
authors.forename: Gloria
authors.initials: G
authors.lastname: Mazzone
authors.affiliation: Chimie ParisTech, CNRS, Institut de Recherche de Chimie Paris (IRCP), PSL Research University, F-75005 Paris, France. marta.alberto@chimie-paristech.fr.
authors.forename: Marta E
authors.initials: ME
authors.lastname: Alberto
authors.affiliation: Dipartimento di Chimica e Tecnologie Chimiche, Università della Calabria, I-87036 Arcavacata di Rende, Italy. bruna.desimone@unical.it.
authors.forename: Bruna C
authors.initials: BC
authors.lastname: De Simone
authors.affiliation: Dipartimento di Chimica e Tecnologie Chimiche, Università della Calabria, I-87036 Arcavacata di Rende, Italy. tiziana.marino65@unical.it.
authors.forename: Tiziana
authors.initials: T
authors.lastname: Marino
authors.affiliation: Dipartimento di Chimica e Tecnologie Chimiche, Università della Calabria, I-87036 Arcavacata di Rende, Italy. nino.russo@unical.it.
authors.forename: Nino
authors.initials: N
authors.lastname: Russo
mesh_terms: D003198:Computer Simulation; D015394:Molecular Structure; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology*; D011166:Porphyrins / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology*; D011789:Quantum Theory; D026082:Singlet Oxygen / Q000737:chemistry; D013329:Structure-Activity Relationship
chemical_list: D017319:Photosensitizing Agents; D011166:Porphyrins; C452433:bacteriochlorin; D026082:Singlet Oxygen
keywords: DFT; TD-DFT; bacteriochlorins; electronic spectra; spin-orbit coupling constants