Enantiopure Double ortho-Oligophenylethynylene-Based Helical Structures with Circularly Polarized Luminescence Activity
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AuthorReiné Díaz, Pablo; Ortuño Guzmán, Ana María; Resa Acosta, Sandra; Álvarez Cienfuegos Rodríguez, Luis; Mota Ávila, Antonio José; Miguel Álvarez, Delia; Cuerva Carvajal, Juan Manuel
Wiley-VCH Verlag GmbH
Chiroptical propertiesCircularly polarized luminescenceFoldamersHelical structuresSupramolecular metallofoldamers
Reiné, P... [et al.] (2021), Enantiopure Double ortho-Oligophenylethynylene-Based Helical Structures with Circularly Polarized Luminescence Activity. ChemPhotoChem. [https://doi.org/10.1002/cptc.202100160]
SponsorshipSpanish Government CTQ2017-85454-C2-1-P CTQ2017-85454-C2-2-P; Instituto de Salud Carlos III Spanish Government European Commission PID2020-113059GB-C21 PID2020-113059GB-C22; Junta de Andalucia European Commission P20.00162; University of Brescia / CBUA; Fondazione Cariplo; Ministry of Education, Universities and Research (MIUR) 2017A4XRCA; Regione Lombardia
In this paper, we describe the optical and chiroptical properties of an enantiopure multipodal ortho-oligophenylethynylene (S,S,S,S)-1 presenting four chiral sulfoxide groups at the extremes. The presence of these groups together with alkynes allows the coordination with carbophilic Ag(I), and/or oxophilic Zn(II) cations, yielding double helical structures in an enantiopure way. In this sense, different behaviors in absorption, fluorescence, ECD and CPL spectra have been found depending on the stoichiometry and nature of the metal. We have observed that Zn(II) coordination favors an intensity increase of the electronic circular dichroism (ECD) spectra of compound (S,S,S,S)-1 yielding an M-helicity in the ortho-oligophenylene ethynylene (o-OPE) backbone. On the other hand, ECD spectra of final Ag(I) complex shows two different bands with an opposite sign to the free ligand, thus giving the P-helical isomer. In addition, circularly polarized luminescence (CPL) exhibit an enhanced intensity and negative sign in both complexes. Computational studies were also carried out, supporting the experimental results.