Supra-molecular architectures

An important challenge in the design of novel conjugated polymers is the synthesis of materials with tailor-made solid-state electronic properties. This section outlines the synthesis of the most significant classes of poly(para-phenylenevinylene)s (PPVs), poly(para-phenylene)s (PPPs), and related structures. Furthermore, this review demonstrates that the chromophoric and electronic properties of conjugated rr-systems are sensitive to their molecular and supra-molecular architecture. 

On the other hand, the G-quadruplex with a twisted supra molecular architecture represents a nice example of a dynamic chiral supramolecular system, when guanine and guanosine molecules are used. Molecular chirality may be used as a tool to assemble molecules and macromolecules into supramolecular structures with dissymmetric shapes. The supramolecular chirality, which results from both the properties and the way in which the molecular components associate, is by constitution dynamic and therefore examples of large-scale transcription of such virtual chirality remain rare. 

Staehelin, L.A. (2003) Chloroplast structure from chlorophyll granules to supra-molecular architecture of thylakoid membranes. Photosynth. Res., 76,... 

Abstract The metal-driven construction of multi-porphyrin assemblies, which exploits the formation of coordination bonds between exocyclic donor site(s) on the porphyrins and metal centers, has recently allowed the design and preparation of sophisticated supra-molecular architectures whose complexity and function begin to approach the properties of naturally occurring systems. Within this framework, meso-pyridyl/phenyl porphyrins (PyPs), or strictly related chromophores, can provide geometrically well-defined connections to as many as four metal centers by coordination of the pyridyl peripheral groups. Several discrete assemblies of various nuclearities, in which the pyridylporphyrins are connected through external coordination compounds, have been constructed in recent years. In this review, we summarize recent work in this field from our and other laboratories. The photophysical properties of some ruthenium-mediated assemblies of porphyrins prepared by our group are also described. 

Vesicles, bicelles and L.C. dispersions. The large number of papers devoted to vesicle and bicelle formulations reflects the paramount importance they have in both applied and theoretical field. As for the above paragraph such aggregates has often been used to stabilize membrane protein and peptides to be studied. Furthermore because of their supra-molecular architecture, they represent the most common fluid nanocontainers for drug delivery applications and the most common mimicking systems in biological membranes studies. 

It is a powerful approach for fabricating supra molecular architectures. Self-assembly of peptides and proteins is a promising route to the fabrication of a variety of molecular materials including nanoscale fibers and fiber network scaffolds (Figure 9.30). The main mechanism for a generic self-assembly is the intermolecular forces that bring the smaller unit together [36, 37]. 

Some authors point out that the precipitation techniques may provide an excessively strong interference into the delicate molecular organization of asphaltenes associates (Figure 10), leading to their irreversible transformation, so that the supra-molecular architecture in solutions of the precipitated material may be different from that in native crude. Consequently, studies of aggregation in crude oil solutions may supply valuable information regarding the manner of asphaltenes-asphaltenes interactions in the presence of other crude oil components. 

Figure 2.2. Proposed architecture for mesostructured metal germanium sulphides. Adamantanoid clusters [Ge4S10]4 link upon addition of a metal salt to form a supra-molecular mesostructured material where surfactant molecules charge balance the negative charge on the framework. Reproduced with permission from [38].

In the fledgling field of super- and supra-molecular liquid crystals, many different terms have been introduced which describe some of the same structures. Figure 1 shows some classical molecular architectures that can be used to describe the gross structures of super- and supra-molecular liquid crystals. For example, two mesogenic units, i.e., molecular entities that can be deployed in material design in order to induce mesophase formation, can... 

Topics which have formed the subjects of reviews this year include excited state chemistry within zeolites, photoredox reactions in organic synthesis, selectivity control in one-electron reduction, the photochemistry of fullerenes, photochemical P-450 oxygenation of cyclohexene with water sensitized by dihydroxy-coordinated (tetraphenylporphyrinato)antimony(V) hexafluorophosphate, bio-mimetic radical polycyclisations of isoprenoid polyalkenes initiated by photo-induced electron transfer, photoinduced electron transfer involving C o/CjoJ comparisons between the photoinduced electron transfer reactions of 50 and aromatic carbonyl compounds, recent advances in the chemistry of pyrrolidino-fullerenes, ° photoinduced electron transfer in donor-linked fullerenes," supra-molecular model systems,and within dendrimer architecture,photoinduced electron transfer reactions of homoquinones, amines, and azo compounds, photoinduced reactions of five-membered monoheterocyclic compounds of the indigo group, photochemical and polymerisation reactions in solid Qo, photo- and redox-active [2]rotaxanes and [2]catenanes, ° reactions of sulfides and sulfenic acid derivatives with 02( Ag), photoprocesses of sulfoxides and related compounds, semiconductor photocatalysts,chemical fixation and photoreduction of carbon dioxide by metal phthalocyanines, and multiporphyrins as photosynthetic models. 

The different methodologies of functionalization of fullerenes, as well as the several types of supra-molecular interactions, allowed the preparation of multiple architectures with interesting properties... 

Due to the significant ability in imaging the native architecture of biological membranes comprising supra molecular assemblies in... 

Cooperativity is crucial in designing molecular constituents for the functional supra-molecular self-assemblies. Especially when increasing numbers of components are involved, high degrees of positive cooperativity are usually d anded for the self-assembly of a desired architecture with high fidelity and specific performance. The double helix is one such functional assembly. 

Abstract Molecular self-assembly is a powerful approach being explored for novel supra-molecular nanostructures and bio-inspired nanomaterials. In this article, we focus on recent research concerning the self-assembly of de novo designed artificial peptides and peptidomimetics into nanofiber structures, specifically towards developing a new class of soft-materials. These nanofiber architectures have potential use not only in biomedical applications, such as 3D-matrix scaffolds for tissue engineering and biomineralization, but also in nanotechnology such as nano-templates and dimension-regulated functional nano-objects. 

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