Supramolecular structures, complex polymeric

Supramolecular Structures Complex Polymeric Systems - Organization, Design and Formation using Interfaces and Cyclic or Complex Molecules... 

In some of these type of polymeric materials there are two forces that organize the polymer strands into a supramolecular structure, and are usually hydrogen bonds and 7r-7r interactions, this happens with the complex [l,2,4,5-C6H2 CH20CH2C(pz)3 4Ag2(BF4)2] .605... 

Summary The analysis of supramolecular structures containing polymers, and the discussion about the effect of polymeric materials with different chemical structures that form inclusion complexes is extensively studied. The effect of the inclusion complexes at the air-water interface is discussed in terms on the nature of the interaction. The entropic or enthalpic nature of the interaction is analyzed. The description of these inclusion complexes with different cyclodextrines with several polymers is an interesting way to understand some non-covalent interaction in these systems. The discussion about the generation and effect of supramolecular structures on molecular assembly and auto-organization processes is also presented in a single form. The use of block copolymers and dendronized polymers at interfaces is a new aspect to be taken into account from both basic and technological interest. The effect of the chemical structure on the self-assembled systems is discussed. 

An example from chemistry is the use of vesicles, liquids, and foams to direct biomimetic mineralization and polymerization. Such templates, that may only have a transitory existence were used to template the assembly of structurally complex, three-dimensional architectures. Subsequently, within supramolecular chemistry, the term "direeted self-assembly" has become more generally understood to include any templated process that brings together molecular components, even if the directing moiety is part of the final structure. " ... 

Various examples of bi- and trifurcated-acceptor interactions have been found in supramolecular structures of metal carbonyl complexes. In (/<-CO)(jU-CHCH3)-[(C5H5)Fe(CO)]2, 91, the bridging carbonyl ligand participates in two C-H- -O hydrogen-bonding interactions with C-H units of the cyclopentadienyl ligands. As a result the dinuclear molecules are self-assembled into polymeric chains [152]. 

Several types of supramolecular self-assembly are found in indenyl and fluorenyl complexes of the alkali metals. It has recently become possible for the first time to elucidate the crystal structures of unsolvated lithium indenide, [LiC9H7] , 26, and sodium fluorenide, [NaCoHgjn, 27 [24]. The crystal structure of 26 closely resembles that of unsolvated lithium cyclopentadienide because it also consists of a polymeric multidecker array in which the Li atoms are symmetrically coordinated by two rj -cyclopentadienyl rings of the indenyl ligands. In contrast, unsolvated sodium fluorenide, 27, forms a two-dimensional supramolecular structure in the solid state (Figure 7.3). In this unusual coordination polymer both the five- and six-membered rings of the fluorene system participate in coordination to sodium via and rj -interactions, respectively. 

Transition metal complexes self-assembled via Tc-interactions are not large in number, although some very interesting examples have been reported. This area of organometallic chemistry is far from being systematically investigated and it is quite difficult to make any predictions concerning possible supramolecular structures of particular compounds. With the exception of several polymeric olefin and arene complexes, the majority of the complexes described in this section are cyclopentadienyl derivatives. 

The self-assembly of supramolecular structures such as host-guest inclusion complexes has r ently bem the focus of a number of research efforts. This approach allows the d ign and building of nanoscale molecular device. It constitutes a conveni t route to realizing the polymerization of hydrophobic molecules (guests) such as thiophene derivatives in aqueous soluticm by using CDs (hosts) and to customizing the polymer ardiitectures 9-11). 

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