Amido ferrocenyl dendrimers

With the dendrimers series shown in Fig. 1, the order of AE° values was H2PO4- > HS04 > Cl" > NO3-. This order can, however, vary greatly from one dendrimer series to the other, and the same can be said of the dendritic effect some dendrimer families (such as the above one) give a strong dendritic effect for a given anion, and others do not. For instance, an amido-ferrocenyl dendrimer with an octabenzylated durene core and 24 redox termini underwent values of the order of what was found for the dendrimer 9-Fc of Fig. 1, far less than 18-Fc of Fig. 1. 

The first ferrocenyl dendrimers suitable for redox recognition contained amido groups attached to the ferrocenyl moiety [23,24], so that the H-bonding interaction with oxo-anions, known from Beer s work with endo-receptors [8-14], would be efficient. At this point, it is essential to point out that mononuclear amidoferrocenes that contain a linear substituent without any special topological requirement for anion recognition display no specific effect [23,24],... 

Recently, Astruc and co-workers have reported the synthesis of dendrimers based on cluster cores.354,355 The reaction of an octahedral molybdenum cluster [n-p,4N]2[Mo6Br8(CF3S03)6] with the dendritic p-NaO-gFfjCfCF CF CF S Me Fc led to the isolation of an air-sensitive Mog-cluster-cored octadecylferrocenyl dendrimer, 300.354 This dendrimer was found to be useful as a detector for ATP2, and the may be advantageous over amido-ferrocenyl containing dendrimers, since the completely oxidized ferrocenium form is stable.354... 

The versatile chemistry of the ferrocenyl moiety has also allowed for the preparation of a large number of dendrimeric structures with this group at the periphery (116-118). A series of dendrimers based upon polypropylenimine cores have been reported (119,120) and star-shaped macromolecules with ferrocene units at the periphery have been produced (121), as well as amido-ferrocene dendrimers (eg, 38) (122). A convergent approach has allowed for the synthesis of dendrimers (39) for which the ferrocene units at the periphery display electronic interaction (123). 

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