Monometallic and bimetallic colloids were prepared in micelles of the block copolymer polystyrene-b-poly-4-vinylpyridine in toluene and analyzed by electron microscopy and various techniques of X-ray analysis. These metal colloids were studied in hydrogenation of cyclohexene, 1,3-cyclooctadiene, and 1,3-cyclohexadiene. A strong influence of the synthetic pathway to the colloids and the type of reducing agent on the catalytic activity of the colloids was found. The lowest activity was observed for N2H4·H2O reduction which is related to a morphology where only a small number of noble-metal colloids is embedded in the micelle core. The highest activity was obtained for the super-hydride reduction where the data suggest the existence of many metal clusters per micelle. The bimetallic Au/Pd colloids with metal ratios 1/5, 1/4, and 1/3 show the highest activity in hydrogenation of cyclohexene to cyclohexane. The Pd monometallic and Au/Pd bimetallic colloids are also rather selective catalysts (both in the homogeneous and a heterogeneous modification), as shown by the hydrogenation of 1,3-cyclooctadiene and 1,3-cyclohexadiene to the corresponding cycloalkenes.

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SUMMARY Novel Pt-containing polymers derived from Zeise salt and polystyrene-polybutadiene diblock (PS-PB) and triblock (SBS) copolymers have been synthesized. The comparison of complex formation peculiarities of Pd-, Rh-, and Pt-containing polymers derived from SBS with 72 wt.-% of PB and PS-PB with 15 wt.-% of PB displayed that a short PB block in PS-PB allows to maintain solubility of organometallic polymers even if intermolecular complexation is probable. Such a solubility was found to be provided by micellization in Pd-, Pt-, and Rh-containing polymers derived from PS-PB. Moreover, crosslinks formed due to complexation were shown to contribute to micellization: iron carbonyl complexes immobilized on PS-PB, where solely intramolecular complexes can be formed, do not provide micellization.

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Three routes to the preparation of nanodispersed metal or metal oxides particles in polymer matrices have been studied. Thermal treatment in air of W-, Mo-and Cr-carbonyl complexes with polyacrylonitrile (PAN) results in the formation of nanometer-size metal oxide particles in a polycyclic polymer. Co-containing polymers were prepared by mixing Co 2 (CO) 8 with a PAN copolymer or an aromatic polyamide in dimethylformamide (DMF). Co 2 (CO) 8 interacts with DMF giving the complex [Co(DMF) 6 ] 2+ [Co(CO) 4 ] -2 . Subsequent thermolysis converts this complex to nanodispersed Co particles. By ferromagnetic resonance and small-angle x-ray scattering, it was found that the average Co particle size depends on the type of polymeric matrix, the thermolysis conditions and the Co loading and varies from 1 to 10 nm.Colloidal metal particles and metal clusters are intriguing because their behavior differs from both bulk metal and isolated metal atoms. The huge specific surface and confinement of charge carriers suggests potential applications as catalysts, as ferrofluids, and as materials for third- harmonic generation (1,2), The principal difficulty in preparing such metal colloids is developing a method to control the particle growth. This problem can be partly solved by carrying out the nucleation and growth process either in solid polymer matrices (3) or in cages (or pores, for example, zeolites) (4) or in organized media such as microemulsions, vesicles or micelles (5). Reactions in such microreactors work with the concept that growth processes are limited in nanostructured matrices by the size of the structures themselves. Here, we discuss another way to control the nucleation and growth process in polymeric matrices which might be especially appealing when the methods listed above cannot be applied, that is, when the polymeric matrix does not form vesicles or micelles. For this case, carrying out the metal colloid formation in solid polymeric matrices can provide size control by changing the type of polymeric matrix, complexation power