Assembly supramolecular

The synthesis and structures of transition metal complexes of anionic cyclo-polypnictogen ligands, e.g. cyclo-P5, are discussed in Section 7.2.1 and 11.2. An exciting recent development involves the use of these complexes as building blocks for the construction of novel supramolecular assemblies, including one-dimensional (ID) and two-dimensional (2D) polymers and even soluble spherical fullerene-like aggregates.Complexes that have been used for this 

In a similar manner, the reaction of 6.28 with CuCl in CH2CI2-CH3CN produces the spherical complex [ Cp Ta(CO)2(t -P4) 6 CuCl g] (6.31). The tantalum complex 6.31 is comprised of 32 core atoms forming four-membered P4 rings and six-membered P4CU2 rings in an extended cubic arrangement with 

Advanced Organic Chemistry, 5th edn., Wiley, New York, 2001, pp. 62-69. 

Steudel, in The Chemistry of Inorganic Ring Systems, ed. R. Steudel, Elsevier, Amsterdam, 1992, pp. 233-254. 

Schiilke, M. T. Averbuch-Pouchot and A. Durif, Z. Anorg. Allg. Chem., 1992, 612, 107. 

In a similar approach, double-stranded helicates of various lengths that were derived from copper and silver-based metallosupramolecular architectures have also been classified by their diffusion properties and estimates of the molecular sizes made [48]. Owing to the ellipsoidal structures, it was necessary to introduce appropriate shape factors to translate the hydrodynamic radii determined directly from the unmodified Stoke-Einstein equation into dimensions that were meaningful for these assemblies. Thus, knowledge of the width of the helicates (determined from the X-ray structure of a single complex in this case) allowed the determination of their lengths from the hydrodynamic radii. The results for a series of these helicates is summarised in Table 9.9. It was further shown that 2D DOSY spectra could be employed to differentiate the helicates of different lengths when present simultaneously in a mixture. 

Structure and schematic rq resentation of the single, double and tetra rosette supramolecular hydrogen-bonded assemblies characterised by diffusion NMR spectroscopy (reproduced with permission from [47], The Royal Society of Chemistry). 

Adapted with permission from [48], Copyright Wiley-VCH Verlag GmbH Co. KGaA. 

This work was supported by NSF Grant No. CHE-0111164 and DOE Grant No. DE-FG03-01ER15257. We thank ChevronTexaco for partial support of E. J. W., Mr. N. R. M. Crawford for assistance with the electronic structure calculations, and Dr. S. A. Baudron for helpful discussions. 

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Tian Y, Fendler J FI, Flungerbuhler FI, Guldi D M and Asmus K-D 1999 Effects of hydrophobic-hydrophilic balance and stereochemistry on the supramolecular assembly of functionalized fullerenes Supramol. Sc/. C 7 67-73... 

A particular point of interest included in these hehcal complexes concerns the chirality. The heUcates obtained from the achiral strands are a racemic mixture of left- and right-handed double heUces (Fig. 34) (202). This special mode of recognition where homochiral supramolecular entities, as a consequence of homochiral self-recognition, result from racemic components is known as optical self-resolution (203). It appears in certain cases from racemic solutions or melts (spontaneous resolution) and is often quoted as one of the possible sources of optical resolution in the biological world. On the other hand, the more commonly found process of heterochiral self-recognition gives rise to a racemic supramolecular assembly of enantio pairs (204). 

Fig. 7. Formation of a supramolecular aggregate composed of a compound containing nine melamine rings (the three-layered nonamelamine derivative A) and nine molecules of neohexylisocyanurate (B). Of the 16 possible conformers that can result, two are shown The first has the nine molecules of B arranged in three rosettes of three molecules each, stacked atop each other in the second, the rosettes are staggered with respect to each other such that the rosettes in the first and third layers of A are aligned with each other, but not with the rosette in the second layer. The supramolecular assembly is stabilized...

Viruses Are Supramolecular Assemblies Acting as Cell Parasites... 

Ribosomes, the supramolecular assemblies where protein synthesis occurs, are about 65% RNA of the ribosomal RNA type. Ribosomal RNA (rRNA) molecules fold into characteristic secondary structures as a consequence of intramolecular hydrogen bond interactions (marginal figure). The different species of rRNA are generally referred to according to their sedimentation coefficients (see the Appendix to Chapter 5), which are a rough measure of their relative size (Table 11.2 and Figure 11.25). 

Supramolecules and supramolecular assemblies including silsesquioxanes and azacrown ethers fragments as liquid crystals with restricted molecular topology 98CC2057. 

Schmittel M, Kalsani V (2005) Functional, Discrete, Nanoscale Supramolecular Assemblies. 245 1-53... 

In this context it is interesting to note that archaea, which possess S-layers as exclusive cell wall components outside the cytoplasmic membrane (Fig. 14), exist under extreme environmental conditions (e.g., high temperatures, hydrostatic pressure, and salt concentrations, low pH values). Thus, it is obvious one should study the effect of proteinaceous S-layer lattices on the fluidity, integrity, structure, and stability of lipid membranes. This section focuses on the generation and characterization of composite structures that mimic the supramolecular assembly of archaeal cell envelope structures composed of a cytoplasmic membrane and a closely associated S-layer. In this biomimetic structure, either a tetraether... 

SUPRAMOLECULAR ASSEMBLIES MADE OF NATURAL STRUCTURAL PROTEINS... 

Keywords. Calcium carbonate. Mineralization, Hyperbranched polymer, Supramolecular assembly. Anionic dendrimer... 

The use of ordered supramolecular assemblies, such as micelles, monolayers, vesicles, inverted micelles, and lyotropic liquid crystalline systems, allows for the controlled nucleation of inorganic materials on molecular templates with well-defined structure and surface chemistry. Poly(propyleneimine) dendrimers modified with long aliphatic chains are a new class of amphiphiles which display a variety of aggregation states due to their conformational flexibility [38]. In the presence of octadecylamine, poly(propyleneimine) dendrimers modified with long alkyl chains self-assemble to form remarkably rigid and well-defined aggregates. When the aggregate dispersion was injected into a supersaturated... 

A supramolecular assembly of macromolecules bearing antenna dendron has been reported. Pyrazole-anchored PBE dendrons were synthesized to examine the coordination behavior to transition-metal cations (Cu, Au, Ag) [31]. Self-assembled metallacycles were found. The Cu-metallacycle further formed luminescent fibers about 1 pm in diameter. The luminescence (605 nm) occurred by the excitation of the dendron (280 nm) and the excitation spectrum was coincident with the absorption spectrum of the dendron, suggesting the antenna effect. Interestingly, the luminescence of the Cu-metallacycle fiber disappeared when the fiber was dissociated into the individual metallacycles in C2H2. 

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