1 research outputs found
Mikroporöse organische Polymere auf Basis tetraedrischer Monomere der Gruppe IV
In this thesis, porous organic polymers were synthesized on the basis of tetrahedral monomers of
the group IV. Their optical properties and porosities were investigated and specifically tuned by
the choice of monomers, reaction conditions or by postmodification.
First, a tetrahedral, silicon-centered monomer with terminal bromides was employed for the
Yamamoto homocoupling (Scheme 1, left). The alkyne functionalities at the central atom allow for
the cleavage of the silicon-carbon-bond, after which the organic fragments of the insoluble
network were identified. The results were compared to a formally structural identical material
that was synthesized via an alternative synthesis route. Furthermore, tetrakis(4-ethynylphenyl)stannane was employed in a screening under Sonogashira-
Hagihara conditions (Scheme 1, right). Fluorescence and porosity of the formally identical
networks were dependent on the chosen reaction conditions. The materials were cleaved at the
tin-carbon bonds with chloroacetic acid to analyze the organic linkers and examine the
completeness of the polymerization.
In addition, networks were screened for the influence of the central atom in the tetrahedral
monomer. The elements of group IV (M = C, Si, Ge, Sn) were used as central units. Irrespectively
of the applied conditions, the carbon-centered materials revealed the highest BET surface areas
whereas the tin-centered ones yielded the lowest. Nevertheless, the absolute dimension of the
surface area is related to the chosen synthesis protocol.
Moreover, postmodification of porous polymers derived from AA’-polymerization of varying
amounts of silicon- and tin-centered monomers was realized. They were selectively cleaved at the
tin-carbon bonds to release fractions of the linkers and to tune porosity and emission color.
Finally, sulfur containing polymers were synthesized from tetrakis(4-ethynylphenyl)silane for
implementation as cathode material in lithium sulfur batteries. The networks showed moderate
activities with capacities up to 750 mAh/g