title: Anilino-Substituted Multicyanobuta-1,3-diene Electron Acceptors: TICT Molecules with Accessible Conical Intersections.
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.
authors.affiliation: Istituto per la Sintesi Organica e la Fotoreattività, Consiglio Nazionale delle Ricerche , Via P. Gobetti 101, 40129 Bologna, Italy.|Dipartimento di Chimica "G. Ciamician", Università di Bologna , Via F. Selmi 2, 40126 Bologna, Italy.
authors.forename: Filippo
authors.initials: F
authors.lastname: Monti
authors.affiliation: Istituto per la Sintesi Organica e la Fotoreattività, Consiglio Nazionale delle Ricerche , Via P. Gobetti 101, 40129 Bologna, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Venturini
authors.affiliation: Dipartimento di Chimica "G. Ciamician", Università di Bologna , Via F. Selmi 2, 40126 Bologna, Italy.
authors.forename: Artur
authors.initials: A
authors.lastname: Nenov
authors.affiliation: Laboratorium für Organische Chemie, ETH Zürich , Vladimir-Prelog-Weg 3, 8093 Zürich, Switzerland.
authors.forename: Francesca
authors.initials: F
authors.lastname: Tancini
authors.affiliation: Laboratorium für Organische Chemie, ETH Zürich , Vladimir-Prelog-Weg 3, 8093 Zürich, Switzerland.
authors.forename: Aaron D
authors.initials: AD
authors.lastname: Finke
authors.affiliation: Laboratorium für Organische Chemie, ETH Zürich , Vladimir-Prelog-Weg 3, 8093 Zürich, Switzerland.
authors.forename: François
authors.initials: F
authors.lastname: Diederich
authors.affiliation: Istituto per la Sintesi Organica e la Fotoreattività, Consiglio Nazionale delle Ricerche , Via P. Gobetti 101, 40129 Bologna, Italy.
authors.forename: Nicola
authors.initials: N
authors.lastname: Armaroli