Dendrimers phosphorus-containing

Polyether dendrimers, phosphorus-containing dendrimers, and polyurethane dendritic wedges also have been characterized by MALDI-TOF. 

Among all types of dendrimers, phosphorus-containing dendrimers [4] that are dendrimers having one phosphorus atom at each branching point play more and more an important role. In this chapter, we will focus on their use as catalysts, for materials, and in biology. Besides our own work, a few other groups have reported the synthesis of phosphorus-containing dendrimers. We can mentioned in particular the first example of any type of phosphoms dendrimers (poly(phosphonium)... 

Divergent Approaches to Phosphorus-Containing Dendrimers and their Functionalization J.-P. Majoral, A.-M. Caminade... 

Divergent Approaches to Phosphorus-Containing Dendrimers and their Functionalization... 

Although the first publication on dendrimers appeared in 1978 [ 1 ] it is only in 1990 that the first report on phosphorus-containing dendrimers was published [2] i.e. after numerous papers devoted to the synthesis of organic dendrimers and practically at the same time than the description of a silicon containing dendrimer. 

The aim of this review is to present the state-of-the-art concerning the synthesis and the chemical properties of phosphorus-containing dendrimers with emphasis made on the specificity introduced by phosphorus. 

Most of the methods of synthesis reported above present some limitations and constraints lack of solubility for polycationic phosphorus-containing dendrimers from generation 3 [2], dendrimers of weak molecular weight [4], difficulties to overcome cross Unking reactions [6], possibility only to incorporate phosphorus groups on the surface of dendrimers [3], etc. 

Even if only a few methods of synthesis of phosphorus-containing dendrimers are reported up to date, it is clear that these macromolecules now constitute a well known class of polymers whose studies appear to be an emerging field of research. 

Even if attention has not been focussed on the physical properties of phosphorus-containing dendrimers in this review, one can mention the high dipole moment values observed for these polymers up to 328 debyes for generation 11. 

In summary, phosphorus-containing dendrimers have their own specificity applications of these derivatives in different areas would be numerous in the near future. Some of these applications are in progress. 

Launay, N., Caminade, A.M., Lahana, R., and Majoral, J.P. (1994) A general synthetic strategy for neutral phosphorus-containing dendrimers. Int. Ed. Engl. 33, 1589-1592. 

Figure 13.9 Phosphorus-containing dendrimer with 96 terminal chlorides R is indicated by the bold type in the structure.

Launay N, Slany M, Caminade A-M, Majoral J-P. Phosphorus-containing dendrimers, easy access to new multi-difunctionalized macromolecules. J Org Chem 1996 61 3799-3805. 

Figure 7.6.6. Phosphorus containing dendrimers forming multiply charged cations.

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

The first neutral phosphorus-containing dendrimers ( phosphodendrimers ) were described in 1994 by Majoral et al., who subsequently substantially expanded the range of compounds. The phosphorus was bonded to other heteroatoms such as N and O [104] and also to carbon [105]. However, dendrimers are also known in which phosphorus atoms are located in the core unit or in the periphery, and also both in the core and at the branching points as well as the periphery [106]. An example with pentavalent phosphorus atoms in the core unit and at the branching points is shown in Fig. 4.54. 

Recently, Majoral et al. described the synthesis of a third-generation phosphorus-containing dendrimer possessing 24 chiral iminophosphine end groups derived from (2S)-2-amino-l-(diphenylphosphinyl)-3-methylbutane (Fig. 11) [32]. The dendritic catalyst was tested in allylic substitution reactions, using rac-(.E)-diphenyl-2-propenyl acetate or pivalate as substrates. The observed enantioselectivities were good to excellent (max. 95% ee) in all reactions. After completion of the catalytic reaction, the catalyst could be reused at least twice after precipitation and filtration. A slight decrease... 

---