Dendritic catalysis has proven to be a potent modern tool for different reactions like hydrogenation and a variety of cross-coupling reactions such as the Heck and Suzuki reaction. The construction of such branched and highly functionalized architectures proved to be challenging and requires endurance and precise synthetic protocols. Therefore, the development of a convenient and robust toolbox to synthesize phosphine-terminated branched or linear multi-substituted structures is of great interest. In this work we present an atom-economic and facile way of introducing phosphine moieties into branched and/or highly functional polymer-based scaffolds utilizing the terminal double-bond motive of allyl groups or 1,2-polyisoprene respectively. The degree of functionalization, solubility and morphological aspects can be targeted by varying the polymer composition, i.e. introducing a second block segment or by the generation of star-shaped polymer architectures. Additionally, the successful introduction of the phosphine motive can be validated by its characteristic and scaffold-independent fingerprint in 1D- and 2D-NMR spectroscopy experiments. As the binding of the catalytically active metal, i.e. palladium(0) and the resulting stoichiometry of the formed complexes is crucial for the efficacy of the resulting catalyst, the binding kinetics are investigated by NMR spectroscopy studies. The presented multivalent ligand systems could be utilized in manifold applications like dendritic or (pseudo)micellar catalysis due to nano-confinement with great potential in the field of multi-phase reactions by showing a simultaneous catalytic and phase-mediating activity.

Simple toolbox for building dendritic and polyisoprene based multidentate phosphine ligand structures and their Pd(0) complexes

2019 Spring National Meeting

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.