Supramolecules field

With the field of hydrogen-bonded electron transfer in its infancy, new frontiers await exploration and numerous issues remain to be addressed. The D—[H]—A supramolecules of the preceding sections define two basic PCET reaction mechanisms ... 

The variety of the examples listed above documents that dendrimer chemistry has attained increasing interest. In this compilation of recent results the trend towards functional and application-oriented molecules including biochemically active, photoswitchable, and polymerlike dendrimers is particularly apparent. Dendrimers cross the boundaries of classical organic chemistry and as new materials will penetrate deeper into the topical fields of nanostructures , supramolecules and polymers in the future. Increasing industrial research on dendrimers and the commercial availability of PAMAM and polyamine dendrimers should stimulate further investigations in this field. 

In 1978, Jean-Marie Eehn introduced the modem concept of supramolecular chemistry, which he defined as the. . chemistry of molecular assemblies and of the inter-molecular bond, "" although the term itself made a much earlier appearance (in Webster s Dictionary in 1903). Traditionally, phrases such as "chemistry beyond the molecule." "the chemistry of the non-covalent bond," and non-molecular chemistry" or even "Lego chemistry" were also used to describe the field. In the beginning, supramolecules mainly comprised two components, a host and a guest, which interact with one another in a nonco-valent fashion (Fig. 1). The area rapidly evolved to... 

H.-S. Kim, S.-M. Choi, J.-H.Lee, P. Busch, S.J. Koza.E.A. Verploegen,B.D. Pate.Uniaxially oriented, highly ordered, large area columnar superstiuctures of discotic supramolecules using magnetic field and surface interactions. Adv. Mater. 20, 1105-1109 (2008)... 

Because of their intellectual and practical importance, and their aesthetic beauty, chemists have longed to mimic such large, multimolecular complexes. The phrase supramolecular chemistry—chemistry beyond the molecule—has been coined to describe this field. Certainly, the host-guest systems we discussed above are simple examples of supramolecules, and the molecular recognition forces we ve enumerated will provide the driving force for assembly. But, when a large number of molecules assembles into one complex system, new issues arise. Here we will summarize some of the general issues associated with supramolecular chemistry, and then we will present some examples of especially successful or informative systems. 

---