Photosensitization supramolecular

H- and J-aggregates Metal phthalocyanines Photophysical properties Photosensitizers Supramolecular systems... 

Su et al. (Xiao et al., 2008) fabricated a new type of thermotropic liquid-crystalline photosensitive supramolecular ionic self-assembly of polyelectrolyte and functional unit azobenzene IL crystal (azo-ILC), where the thermal and phase behaviors can be modulated by changing the spacer length (methylene units in azo). Ma et al. (Ma et al., 2008) found that the addition of very small amounts of an alcohol or water into tri-n-decylmethylphosphonium chloride and bromide salts (IPlOX) induced the formation of liquid crystalline, where strong association between the hydroxyl groups of alcohol or water and the head groups of IPlOX is indicated. 

Given the actual scenario, one can state that the emerging field of nanotechnology represents new effort to exploit new materials as well as new technologies in the development of efficient and low-cost solar cells. In fact, the technological capabilities to manipulate matter under controlled conditions in order to assemble complex supramolecular structures within the range of 100 nm could lead to innovative devices (nano-devices) based on unconventional photovoltaic materials, namely, conducting polymers, fuUerenes, biopolymers (photosensitive proteins), and related composites. 

Torre G, Nicolau M, Torres T (2001) In Nalwa HS (ed) Supramolecular photosensitive and electroactive materials. Academic, New York, p 1... 

Ferro, S., Jori, G., Sortino, S., Stancanelli, R., Nikolov, P., Tongon, G., Ricchelli, F., and Mazzaglia, A. (2009). Inclusion of 5-[4-(l-dodecanoylpyridinium)-10,15,20-triphenylpor-phine in supramolecular aggregates of cationic amphiphilic cyclodextrines Physic-chemical characterization of the complexes and strengthening of the antimicrobial photosensitizing activity. Biomacromolecules 10(9), 2592-2600. 

Nalwa, H.S. Supramolecular Photosensitive and Electmacttve Material, Elsevier Science, New York. NY, 2001. 

In the design of such supramolecular dyads, a number of prerequisites should to be considered. In order to obtain a true supramolecular assembly there needs to be substantial interaction between the different components of the assembly. There should, however, not be any substantial changes in the physical properties of these components, but their combination should lead to some new and novel characteristics. The combination of components should have properties over and above those of the separate components, without destroying their individual characters. Molecular dyads may, for example, contain a photosensitizer and an electron or energy donor or acceptor. An example of such a combination of a sensitizer and an electron donor is the Ru-PTZ dyad [14] shown in Figure 6.21. In this assembly, the ruthenium center is the sensitizer, S, and the phenothiazine... 

Inoue, Y. (2004) Enantiodifferentiating photosensitized reactions, in Chiral Photochemistry (Molecular and Supramolecular Photochemistry), Vol. 11... 

In this report, we will describe some of our studies aimed at (i) obtaining new inorganic photosensitizers by second-sphere modification of known ones, and (ii) assembling photosensitizer units with other molecular components in discrete, covalently bound supramolecular structures. Studies of type (i), besides their intrinsic interest, have some relevance to the problem of how the properties of a photosensitizer are modified by inclusion in a supramolecular structure. Systems of type (ii) would be useful to study the basic processes of intramolecular electron and energy transfer involved in the performance of molecular photochemical devices. 

Cyano-bridged Supramolecular Systems Containing the Ru(bpy)22+ Photosensitizer Unit. 

Based on their easily tunable photophysical and redox properties, transition metal complexes are versatile components to be used in the construction of photochemical molecular devices. The studies presented in this article show that the combination of the Ru(bpy)22+ photosensitizer and cyanide bridging units allows the synthesis of a variety of polynuclear systems that exhibit interesting photochemical properties. Depending on the nature of the attached metal-containing units, supramolecular systems can be obtained that undergo efficient photoinduced intramolecular energy or electron transfer processes. 

In the modified zeolite sensitization study, a significant enhancement of product ee was reported to occur by the introduction of a chiral sensitizer into the zeolite supercages that otherwise give an almost racemic product [47]. Further supramolecular approaches to the enantiodifferentiating photosensitization will lead to more solid conclusions on the mechanisms and factors that control supramolecular photochirogenesis and open a new channel to asymmetric supramolecular photochemistry in the near future see Chap. 9. 

---