| Abstract
| - Recent studies revealed that catalysts, prepared on dendronized support, frequently exhibitenhanced activity and selectivity as compared to their non-dendronized analogues. Regretfully, in earlystudies of the supported dendritic catalysis, no particular attention was paid to the coordinative nature ofthe dendritic backbone. In this study, we functionalized Wang polystyrene support with three types of dendritictemplates: poly(aril benzyl ether), poly(aryl benzyl thioether), and poly(aryl benzyl amine). Thesedendronized resins were further decorated with phosphine ligands on the periphery and complexed with aPd(0) catalytic precursor. The catalysis of the Heck and Suzuki reactions of bromobenzene with the firstto third generation supported dendritic catalysts was examined and compared to that of the non-dendriticanalogues. All of the examined reactions revealed a positive dendritic effect, reflected in up to 5-fold increasein yield, in the most prominent case. The reasons for the observed effect are the proximity of the ligatingsites translated into reduced cross-linking and, probably, the increased distance of the catalyst from thepolymer matrix. We proved, however, that the latter could not be achieved with a linear spacer. Althoughthe Suzuki reaction was rather insensitive to the backbone structure, the Heck reaction catalysis at 80 °Cexhibited substantial sensitivity to the nature of the dendritic backbone, with the polyether structuredemonstrating the best outcome. This is the first demonstration of the influence of the coordinative abilityof the backbone on the activity of a supported dendritic catalyst.
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