Synthetic methods for dendritic molecules

Bibliography and Notes for Chapter 2 Synthetic methods for dendritic molecules  

Review articles are indicated by the words Review(s) or Book/Books in bold-faced type. 

Moorefield, F. Vogtle, Dendrimers and Dendrons Concepts, Syntheses, Applications, Wiley-VCH, Weinheim 2001  

18 a) M. Malkoch, K. Schleicher, E. Drock-enmuller, C. J. Hawker, T. P. Russell, 

Merrifield,/. Am. Chem. Soc. 1963, 85, 2149-2154. Reviews R. B. Merrifield, Angew. Chem. 1985, 97, 801-812 Angew. Chem. Int. Ed. 1985, 24, 799-810 R. B. Merrifield, Science 1986, 232, 341—347 Book F. Zaragoza Dorwald, Organic Synthesis on Solid Phase, 2nd Edit., Wiley-VCH, Weinheim 2002. 

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This Topics volume also shows that in the development of dendrimer chemistry there is still a need for efficient synthetic methods ensuring multiple high-yield conversion and leading to more or less pure (monodisperse, structurally perfect) dendritic molecules. Large libraries of imperfect substances are often formed at higher generations, only differing in small structural details. 

Development of the dendritic method for macroassembly did not simply arise from the first examples of deliberately prepared branched molecules. Rather, it was a logical progression of synthetic approaches derived from the efforts of countless researchers to realize new materials with novel properties and uses. 

The general area of dendritic and hyperbranched polymers has received remarkable attention over the past decade. New properties not available with linear polymers have been demonstrated. For example, evidence has been provided that supports the existence of considerable space for the encapsulation of small molecules, and this has led to the idea of a dendritic box" (69j. A severe problem with dendrimers is their timesynthetic methods that form hyperbranched materials that may exhibit many of the advantageous properties of dendritic macromolecules have been receiving significant attention (70j. 

To characterize dendrimers, analytical methods used in synthetic organic chemistry as well as in macromolecular chemistry can be applied. Mass spectrometry and NMR spectroscopy are especially useful tools to estimate purity and structural perfection. To get an idea of the size of dendrimers, direct visualization methods such as atomic force microscopy (AFM) and transmission electron microscopy (TEM), or indirect methods such as size exclusion chromatography (SEC) or viscosimetry, are valuable. Computer aided simulation also became a very useful tool not only for the simulation of the geometry of a distinct molecule, but also for the estimation of the dynamics in a dendritic system, especially concerning mobility, shape-persistence, and end-group disposition. 

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