Platinum chain-length effects

In many papers in which the reaction rates or adsorption coefficients of a series of substrates were obtained the effect of structure is discussed only qualitatively. Rilzicka and Cerveny (5) found that the rate of hydrogenation of 1-olefins C6-C17 in ethanol under usual conditions on platinum, palladium and rhodium catalysts decreased monotonically with the chain length. Since in this olefinic series the chain length did not affect (68) the relative adsorptivity of olefins, as demonstrated in Table II, the observed phenomenon may be explained only by the effect exerted by the chain length on the rate constants. Since, moreover, the polar effect of substituents in this series is virtually the same, an explanation can be sought in the steric hindrance of the adsorbed double bond by the free end of the olefin molecule. The trans isomers were adsorbed much more weakly than the respective cis... 

The mesomorphism of silver(I) complexes of poly(alkoxy)stilbazoles has been reviewed recendy. However, it is appropriate to cover this work here in order to see the effect of an anion on mesomorphism in cationic complexes and to allow some comparison to be made with the complexes described in the preceding section. In these studies, there were two main variables, namely the substitution pattern of the stilbazole used and the nature of the anion. The former was varied in the same way as for the palladium and platinum complexes just described, while the latter was either triflate or an alkylsulfate whose chain length was varied. 

Gololobov, A., Bekk, L, Bragina, G., et al. (2009). Platinum Nanoparticle Size Effect on Specific Catalytic Activity in n-Alkane Deep Oxidation Dependence on the Chain Length of the Paraffin, Kin. Ratal, 50, p[. 830-836. 

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