ROESLER  GROUP HOMEPAGE
 
synthetic inorganic and organometallic chemistry
 


                                                      Current Research

Research Areas Dendrimers with Inorganic Skeletons
Dendrimers [1-3] (from the Greek “dendron” ~ three, branch and “meros” ~ part) are highly branched, regular, three-dimensional monodisperse macromolecules with a branch occurring regularly at each monomer unit or after a succession of monomer units. The hallmark of dendrimer chemistry is the ability to synthesize in a controlled manner very high molecular weight polymers with narrow molecular weight distributions.


During the last decade, dendrimer chemistry has expanded in a spectacular fashion, as illustrated by numerous recent reviews [1-8]. This dramatic development was driven by the practical applications dendrimers found as inkjet inks and toners, in vitro diagnostics, MRI contrast agents, and size standards. The envisaged applications are much more numerous and it is estimated that large molecules with dendritic architecture will have a major technological impact in the future. The proven capability of dendrimers to host, either in the internal cavities or on the surface, smaller molecules that can be later released in a slow equilibrium makes dendrimers promising drug delivery agents, as well as slow delivery agents for perfumes and herbicides. The use of dendrimers as catalyst carriers aims to combine the advantages of homogeneous and heterogeneous catalysis. The large light absorption and focalisation capability of dendrimers functionalized on the periphery with chromophores can be exploited in application as photoactive materials (i.e. light harvesting devices). Other applications include surfactants, polymer additives, thin films and coatings,  sensors, and nanocomposites.


Although the majority of dendrimers reported so far have organic backbones, a variety of dendrimers containing heteroatoms (Si, P, B, Ge, Bi) have been synthesized as well [7, 8]. In most of these cases though, the heteroatoms were intercalated into the organic skeleton. The only dendrimers with an inorganic framework reported to date are first and second generation silicon derivatives. At the same time, a large variety of "classical" inorganic polymers are known and many of them are manufactured on an industrial scale. Among these,  polyphosphazenes, polysiloxanes and polysilanes are most widely used.
Our group designs and synthesizes dendrimers with an inorganic skeleton. These molecules will exploit the special properties of the inorganic frameworks in order to produce dendritic materials with properties superior to the organic analogues.  Primarily targeted are dendrimers with applications as photoactive materials and drug delivery agents.


[1] J. Issberner, R. Moors, F. Vögtle, Angew. Chem. Int. Ed. Engl. 1994, 33, 2413. [2] A. Archut, F. Vögtle, Chem. Soc. Reviews 1998, 27, 233. [3] A. W. Bosman, H. M. Janssen, E. W. Meijer, Chem. Rev. 1999, 99, 1665. [4] D. A. Tomalia, A. M. Naylor, W. A. Goddard III, Angew. Chem. Int. Ed. Engl. 1990, 29, 138. [5] S. Hecht, J. M. J. Fréchet, Angew. Chem. Int. Ed. 2001, 40, 74. [6] A. Adronov, J. M. J. Fréchet, Chem. Commun. 2000, 1701. [7] J.-P. Majoral, A.-M. Caminade, Chem. Rev. 1999, 99, 845. [8] H. Frey, C. Lach, K. Lorenz, Adv. Mater. 1998, 10, 279.

Books on dendrimers:
G. R. Newkome, C. N. Moorefield, F. Vögtle, Dendrimers and Dendrons, Wiley-VCH, Weinheim 2001.
F. Vögtle, Ed., Topics in Current Chemistry, Vol. 197, Dendrimers, Springer, Berlin 1998, and Vol. 210, Dendrimers II, Springer, Berlin 2000.
Books on inorganic polymers:
J. E. Mark, H. R. Allcock, R. West, Inorganic Polymers, Prentice Hall, New Jersey, 1992.
U. Schubert, N. Hüsing, Synthesis of Inorganic Materials, Chap. 5, Wiley-VCH, Weinheim, 2000.

More information on dendrimer research can be found at:
Dendrimer Research at Berkley, Fréchet Group
Dendrimer Research in Berlin, Vögtle Group
Dendrimer research at Akron, Newkome Group
Phosphorus Dendrimer Research in Toulouse, Majoral Group
Dendrimer Research at Stanford
Dendrimer Research at Michigan Molecular Institute
Phosphorus Dendrimer Research at Dendrichem
PAMAM Dendrimers at Dendritech Inc.
Dendrimer Research at IBM
Who's Who in Dendrimer Research
More dendrimer links
A. N. Shipway, Review on Dendrimer Research
More information on inorganic polymers can be found at:
Inorganic Polymers at PennState, Allcock Group
Inorganic Polymers at the University of Toronto, Manners Group
School of Polymers at the University of Southern Mississippi
Phosphorus Dendrimer Research in Tolouse, Majoral Group


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