Comparison of AB2 and AB4 monomers in ferrocene-cored benzyl ether dendrimers

Ferrocene-cored unsymmetric and symmetric arylalkyl ether dendrimers based on an AB2 monomer (3,5-dihydroxybenzyl alcohol) were prepared. Their electrochemical properties were compared with the unsymmetric and symmetric ferrocene-cored dendrimers based on a relatively rigid and three-dimensionally disposed AB4 monomer. The thermodynamics and kinetics of heterogeneous electron transfer in these dendrimers show that G2n of AB2 dendrimers behave similar to Gn of AB4 dendrimers. For example, the redox reaction shows significant irreversibility especially at higher scan rates in the case of G4 didendron based on AB2 monomer and G2 didendron based on AB4 monomer. Despite the fact that AB4 building blocks are more rigid, the effective encapsulation in both these dendrimers are similar. This result is attributed to the three dimensional disposition of the branching points in the AB4 monomer.