Surface-block dendrimer

In the case of surface-block dendrimers, the dendrimer periphery exhibits different functionalities in specific molecular segments. They are formed by coupling of dendrons differing in the nature of their terminal functionalities to a common core unit (cf. Section 3.2.1) [6, 10]. 

Phosphorus-containing surface-block dendrimers can be prepared by a method developed by Majoral et al. [57] (Fig. 3.9). 

Fig. 3.8 Convergent synthesis of a bifunctionalised dendrimer with two different peripheral groups in separate molecular segments (surface-block dendrimers)...

Surface-block dendrimer with different peripheral groups in separate segments of the molecule. 

Fig. 2. Schematic drawing of layer-block, segment-block, and surface-block dendrimers...

All these experiments give dendrons possessing either a vinyl, a primary amino, a bisphosphino, or an azido group at the level of the core. Other functional groups can be incorporated [30,31]. These compounds are useful precursors of multidendritic systems. Various surface-block dendrimers can be prepared from these macromolecules. For instance, a Michael addition between dendron 17c-[G 3] (100% excess) and dendron 15b-[G 3] at 90°C induces the formation of dendrimer 20-[G 3]-[G 3] (Scheme 13). This dendrimer possesses two different faces 16 dimethylamino groups on one side, 16 nitrile groups on the other side. 

Scheme 14. Synthesis of the surface-block and layer-block dendrimer 21-[G 3]-[[G 3]2]2...

Maraval V, Laurent R, Donnadieu B, Mauzac M, Caminade AM, Majmal JP (2000) Rapid synthesis of phosphoms-containing dendrimers with controlled molecular architectures first example of surface-block, layer-block, and segment-block dendrimers issued from the same dendron. J Am Chem Soc 122 2499-2511... 

All the fullerene-containing dendrimers reported to date have been prepared with a Cgo core but never with fullerene units at their surface or with Cgg spheres in the dendritic branches. We have recently started a research program on the synthesis of dendrons substituted with fullerene moieties. These fulleroden-drons are interesting building blocks for the preparation of monodisperse fullerene-rich macromolecules. In addition, they are also amphiphilic compounds capable of forming stable Langmuir films at the air-water interface. 

Leon, J.W., Kawa, M., and Frechet, J.M.J. (1996) Isophthalate ester-terminated dendrimers versatile nanoscopic building blocks with readily modifiable surface functionalities. J. Am. Chem. Soc. 118, 8847-8859. 

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