Medina Rivero, SamaraAlonso-Navarro, Matías J.Tonnelé, ClaireMarín-Beloqui, Jose M.Suárez-Blas, FátimaClarke, Tracey M.Kang, SeongsooOh, JuwonRamos, MarKim, DonghoCasanova, DavidSegura Castedo, José LuisCasado, Juan2024-04-082024-04-082023J. Am. Chem. Soc. 2023, 145, 50, 27295–273060002-78631520-512610.1021/jacs.3c06916https://hdl.handle.net/20.500.14352/102813A new family of molecules obtained by coupling Tröger’s base unit with dicyanovinylene-terminated oligothiophenes of different lengths has been synthesized and characterized by steady-state stationary and transient timeresolved spectroscopies. Quantum chemical calculations allow us to interpret and recognize the properties of the stationary excited states as well as the timedependent mechanisms of singlet-to-triplet coupling. The presence of the diazocine unit in Tröger’s base derivatives is key to efficiently producing singletto-triplet intersystem crossing mediated by the role of the nitrogen atoms and of the almost orthogonal disposition of the two thiophene arms. Spin−orbit coupling-mediated interstate intersystem crossing (ISC) is activated by a symmetry-breaking process in the first singlet excited state with partial charge transfer character. This mechanism is a characteristic of these molecular triads since the independent dicyanovinylene-oligothiophene branches do not display appreciable ISC. These results show how Tröger’s base coupling of organic chromophores can be used to improve the ISC efficiency and tune their photophysics.engjournal articlerestricted access547Química orgánica (Química)2306 Química Orgánica