Hierarchic assemblies

It is particularly important to study process phenomena under dynamic (rather than static) conditions. Most current analytical techniques are designed to determine the initial and final states of a material or process. Instmments must be designed for the analysis of materials processing in real time, so that the cmcial chemical reactions in materials synthesis and processing can be monitored as they occur. Recent advances in nuclear magnetic resonance and laser probes indicate valuable lines of development for new techniques and comparable instmmentation for the study of interfaces, complex hquids, microstmctures, and hierarchical assemblies of materials. Instmmentation needs for the study of microstmctured materials are discussed in Chapter 9. 

To be successful in these applications, it is important that materials can self-assemble into precisely defined structures. Peptide-based polymers have many advantages over conventional synthetic polymers since they are able to hierarchically assemble into stable, ordered conformations [4]. Depending on the substituents of the amino acid side chain, polypeptides are able to adopt a multitude of... 

Jiang, Y., Li, H., Zhu, L., Zhou, J. M., and Perrett, S. (2004). Amyloid nucleation and hierarchical assembly of Ure2p fibrils. Role of asparagine/glutamine repeat and nonrepeat regions of the prion domains./. Biol. Chem. 279, 3361-3369. 

Jones, E. M., and Surewicz, W. K. (2005). Fibril conformation as the basis of species- and strain-dependent seeding specificity of mammalian prion amyloids. Cell 121, 63-72. Kad, N. M., Myers, S. L., Smith, D. P., Smith, D. A., Radford, S. E., and Thomson, N. H. (2003). Hierarchical assembly of beta2-microglobulin amyloid in vitro revealed by atomic force microscopy./. Mol. Biol. 330, 785-797. 

In general, dendrimer syntheses involves hierarchical assembly strategies that require the following construction components ... 

Assembly by intervention of other components ( crystalase enzyme). Information-controlled assembly. Hierarchic assembly... 

Sisson A, Papp I, Landfester K, Haag R (2009) Functional nanoparticles from dendritic precursors hierarchical assembly in miniemulsion. Macromolecules 42 556-559... 

The third section describes the hierarchy and supramolecular chirality of molecular assemblies in the crystalline state. The steroidal molecules construct hierarchical assemblies on the basis of sequential information, as in the case of proteins. The notable feature is that each hierarchical assembly exhibits supramolecular chirality, such as three-axial, tilt, helical, and bundle chirality. On the other hand, the primary ammonium salts construct hierarchical hydrogen bonding networks which, in some cases, create supramolecular chirality from achiral components. The creation of chirality can be interpreted from a topological viewpoint, leading us to define the handedness of the supramolecular chirality. At the end of this section we present the general concept that molecular-level information on organic substances can be expressed by their assemblies through non-covalent interactions. 

Since the steroidal molecules are highly asymmetric, the resulting hierarchical assemblies may have the corresponding three-dimensional structures with supramolecular chirality. Starting from molecular chirality, each assembly must be chiral. In this context, we encountered a new problem, how we describe such molecular and supramolecular chirality. The first idea is that the steroidal molecules are analogous to a vertebrate animal which has three-axial chirality based on three directions such as head-leg, right-left, and belly-back. The three-axial chirality enables us to determine the three-axes of the hierarchical assemblies, as in the case of the helices of proteins and DNA. 

Expression of Supramolecular Chirality in Hierarchical Assemblies 26.4.2.1 Three-Axial Chirality... 

Whang D, Jin S, Lieber CM (2003) Nanolithography using hierarchically assembled nanowire masks. Nano Lett 3 951-954... 

As anticipated already, metalation of the ruthenium-mediated multiporphyrin adducts described above introduces new sites for further axial coordination and basically makes them suitable for being used as building blocks in the hierarchical assembly of higher order adducts. 

Hybridization with Nanomaterials Toward Hierarchic Assemblies. 76... 

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