%0 Journal Article
%A Medina Rivero, Samara
%A Alonso-Navarro, Matías J.
%A Tonnelé, Claire
%A Marín-Beloqui, Jose M.
%A Suárez-Blas, Fátima
%A Clarke, Tracey M.
%A Kang, Seongsoo
%A Oh, Juwon
%A Ramos, Mar
%A Kim, Dongho
%A Casanova, David
%A Segura Castedo, José Luis
%A Casado, Juan
%T V-Shaped tröger oligothiophenes boost triplet formation by CT mediation and symmetry breaking
%D 2023
%@ 0002-7863
%@ 1520-5126
%U https://hdl.handle.net/20.500.14352/102813
%X A 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 displayappreciable ISC. These results show how Tröger’s base coupling of organic chromophores can be used to improve the ISC efficiency and tune their photophysics.
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