Synthesis and supramolecular association of immobilized NCN-pincer platinum(II) complexes on hyperbranched polyglycerol supports

Pertosylation of hyper-branched polyglycerol (M-n = 2000; M-w/M-n = 1.3) followed by partial displacement of the tosyl groups with carboxylic acid functionalized NCN-pincer platinum(II) complexes [PtI-2,6-(NMe2CH2)(2)C6H2-4-COOH], resulted in covalent attachment of the NCN-pincer complexes to the polyglycerol. These functionalized hyperbranched macromolecules have been characterized by H-1, C-13, and Pt-195 NMR, UV-visible, and IR spectroscopy. The presence of Pt and I atoms renders them directly visible by transmission electron microscopy (TEM) without staining procedures, which offers images of associated hyperbranched macromolecules. TEM micrographs show disk-shaped structures with a small size-distribution (15-20 nm), and characteristic core-shell ring structures. The thickness of the corona observed in TEM could be correlated with the substitution degree with pincer platinum moieties.