The structural transformation and catalytic properties of metal/polymer nanocomposites derived from hypercross-linked polystyrene (HPS) exhibiting both microporosity and macroporosity, and filled with Pt nanoparticles, are investigated in the direct oxidation of L-sorbose to 2-keto-L-gulonic acid. Transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, anomalous small-angle X-ray scattering, and catalytic studies suggest that the catalytically active species, nanoparticles of mixed composition with a mean diameter of 1.6 nm, develop after the initial induction period. At the highest selectivity (96.8%) at 100% L-sorbose conversion, the catalytic activity is measured to be 2.5 × 10-3 mol/mol Pt-s, which corresponds to a 4.6-fold increase in activity relative to the Pt-modified microporous HPS previously reported. This substantial increase in catalytic activity is attributed to the presence of macropores, which facilitate mass transport and, consequently, accessibility of the nanoparticle surface for reactants.

The Suzuki-Miyaura cross-coupling reaction of ArX (I, Br) with Ar¢B(OH) 2 , catalyzed by Pd-containing water-soluble micelle formed by PS-PEO copolymer and N-cetylpyridinium chloride as a surfactant, was studied in water and methanol. The reaction was performed under mild conditions (temperature up to 50°C) and the catalyst can be recycled (5 runs) by ultrafiltration without any loss of its catalytic activity. The phenomenon was observed, consisting in growing Pd-nanoparticle size because the small nanoparticles dissolve to form larger nanoparticles in the course of reaction as well as in the presence of the only reagent, ArI. In the latter case, additionally, the formation of very small, not completely dissolved Pd nanoparticles, obviously having a high catalyst activity, is observed. This observation, together with the catalyst activity data might have an implication for a leaching mechanism for the studied catalytic system.

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A new family of polysilsesquioxanes colloids was synthesized by hydrolytic condensation of a functionalized precursor N-(6-aminohexyl)aminopropyltrimethoxysilane (AHAPS), H2N(CH2)6NHCH2CH2CH2Si(OCH3)3, and studied using small-angle X-ray scattering, transmission electron microscopy, liquid and solid state NMR, elemental analysis, and other methods. The PAHAPS (polymerized AHAPS) structure is highly functionalized and its functionality can be varied by protonation of the amino groups. This allows varying the local ordering in the PAHAPS colloids, including formation of highly ordered lamellar structures when the AHAPS precursor is hydrolyzed in pure water. By varying the type of solvent (water or THF), one can vary the macrostructure and properties (for example, to impart colloidal solubility) of PAHAPS. These features make PAHAPS a robust polymer material synthesized in a one-pot reaction procedure. As amino groups (protonated or not) easily interact with the majority of transition-metal compounds, PAHAPS colloids can template a variety of particles of interest:  magnetic, semiconductor, metal, or metal oxides with a small variation in the synthetic procedure. Here, formation of narrowly distributed discrete Pt nanoparticles packed within PAHAPS colloids (Pt content reaching 36 wt % without particle agglomeration) is described. The dependence of Pt nanoparticle and PAHAPS colloid sizes on metal compound and reducing agent types is demonstrated.