π-Conjugated stannole copolymers synthesised by a tin-selective Stille cross-coupling reaction

verfasst von
Isabel-Maria Ramirez y Medina, Markus Rohdenburg, Pascal Rusch, Daniel Duvinage, Nadja C. Bigall, Anne Staubitz
Abstract

The synthesis of four well-defined conjugated polymers TStTT1-4 containing unusual heterocycle units in the main chain, namely stannole units as building blocks, is reported. The stannole-thiophenyl copolymers were generated by tin-selective Stille coupling reactions in nearly quantitative yields of 94% to 98%. NMR data show that the tin atoms in the rings remain unaffected. Weight-average molecular weights (Mw) were high (4900-10 900 Da and 9600-21 900 Da); and molecular weight distributions (Mw/Mn) were between 1.9 and 2.3. The new materials are strongly absorbing and appear blue-black to purple-black. All iodothiophenyl-stannole monomers St1-4 and the resulting bisthiophenyl-stannole copolymers TStTT1-4 were investigated with respect to their optoelectronic properties. The absorption maxima of the polymers are strongly bathochromically shifted compared to their monomers by about 76 nm to 126 nm in chloroform. Density functional theory calculations support our experimental results of the single stannoles St1-4 showing small HOMO-LUMO energy gaps of 3.17-3.24 eV. The optical band gaps of the polymers are much more decreased and were determined to be only 1.61-1.79 eV. Furthermore, both the molecular structures of stannoles St2 and St3 from single crystal X-ray analyses and the results of the geometry optimisation by DFT confirm the high planarity of the molecules backbone leading to efficient conjugation within the molecule.

Organisationseinheit(en)
Institut für Physikalische Chemie und Elektrochemie
PhoenixD: Simulation, Fabrikation und Anwendung optischer Systeme
Externe Organisation(en)
Universität Bremen
Universität Leipzig
Typ
Artikel
Journal
Materials Advances
Band
2
Seiten
3282-3293
Anzahl der Seiten
12
Publikationsdatum
21.05.2021
Publikationsstatus
Veröffentlicht
Peer-reviewed
Ja
ASJC Scopus Sachgebiete
Werkstoffwissenschaften (insg.), Chemie (sonstige)
Elektronische Version(en)
https://doi.org/10.1039/d1ma00104c (Zugang: Offen)