A theoretical investigation based on DFT, TD-DFT, and CASSCF/CASPT2 methods has been carried out to elucidate the photophysics of two anilino-substituted pentacyano- and tetracyanobuta-1,3-dienes (PCBD and TCBD, respectively). These molecules exhibit exceptional electron-accepting properties, but their effective use in multicomponent systems for photoinduced electron transfer is limited because they undergo ultrafast (∼1 ps) radiationless deactivation. We show that the lowest-energy excited states of these molecules have a twisted intramolecular charge-transfer character and deactivate to the ground state through energetically accessible conical intersections (CIs). The topology of the lowest-energy CI, analyzed with a linear interpolation of the two branching-space vectors (g and h), indicates it is a sloped CI, ultimately responsible for the ultrafast deactivation of this class of compounds.
Anilino-Substituted Multicyanobuta-1,3-diene Electron Acceptors: TICT Molecules with Accessible Conical Intersections / Monti, Filippo; Venturini, Alessandro*; Nenov, Artur; Tancini, Francesca; Finke, Aaron D.; Diederich, François; Armaroli, Nicola. - In: JOURNAL OF PHYSICAL CHEMISTRY. A, MOLECULES, SPECTROSCOPY, KINETICS, ENVIRONMENT, & GENERAL THEORY. - ISSN 1089-5639. - ELETTRONICO. - 119:43(2015), pp. 10677-10683. [10.1021/acs.jpca.5b09291]
Anilino-Substituted Multicyanobuta-1,3-diene Electron Acceptors: TICT Molecules with Accessible Conical Intersections
Monti, Filippo;Nenov, Artur;TANCINI, FRANCESCA;Armaroli, Nicola
2015
Abstract
A theoretical investigation based on DFT, TD-DFT, and CASSCF/CASPT2 methods has been carried out to elucidate the photophysics of two anilino-substituted pentacyano- and tetracyanobuta-1,3-dienes (PCBD and TCBD, respectively). These molecules exhibit exceptional electron-accepting properties, but their effective use in multicomponent systems for photoinduced electron transfer is limited because they undergo ultrafast (∼1 ps) radiationless deactivation. We show that the lowest-energy excited states of these molecules have a twisted intramolecular charge-transfer character and deactivate to the ground state through energetically accessible conical intersections (CIs). The topology of the lowest-energy CI, analyzed with a linear interpolation of the two branching-space vectors (g and h), indicates it is a sloped CI, ultimately responsible for the ultrafast deactivation of this class of compounds.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.