Controlled spatial distribution of tris(2,2′-bipyridine)ruthenium cation ([Ru(bpy)3]2+) in aluminum containing mesoporous silicas

Sohmiya, Minoru; Ogawa, Makoto

doi:10.1016/j.micromeso.2010.12.023

Cited by 15 publications

(5 citation statements)

References 44 publications

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“…The aforementioned valuable effects of nanosheet materials can be exploited for developing photochemical reaction systems and photofunctional materials. However, the mechanism underlying these effects has not been claried in detail; in addition, dye molecules easily form aggregates on inorganic surfaces, which may decrease their excited lifetimes 31 and result in low photoactivity. Thus, we believe that clarication of the mechanism of such effects and control of the assembly structure of dye molecules on inorganic surfaces are important subjects in photochemical materials chemistry.…”

Section: Introductionmentioning

confidence: 99%

Structure resembling effect of clay surface on photochemical properties of meso-phenyl or pyridyl-substituted monocationic antimony(v) porphyrin derivatives

2015

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Four types of meso-phenyl or pyridyl-substituted monocationic antimony(V) porphyrin derivatives (Sb V Pors)-5, 10,15,20-tetraphenyl; 5,10,15-triphenyl-20-mono(4-pyridyl); 5,15-diphenyl-10,20-di(4pyridyl); and 5,10,15,20-tetra(4-pyridyl)porphyrinato dihydroxo antimony(V) chloride-with different hydrophobicities were synthesised, and their photochemical properties on anionic clay were investigated. The absorption and fluorescence behaviour of the Sb V Pors were strongly affected by complex formation with clay. Interestingly, the absorption transition probabilities and fluorescence quantum yields of the Sb V Pors prominently increased on the clay surface. The more hydrophobic Sb V Por showed greater absorption transition probability increase and fluorescence quantum yield enhancement.These unique effects of the highly flat clay surface on the photochemical behaviour of Sb V Por were discussed mainly from the viewpoint of transition probability, by using the potential energy curves of Sb V Por with and without clay. For the more hydrophobic Sb V Por, the molecular structure of the ground and excited states on the clay surface tended to become similar because of the strong hydrophobic interaction between porphyrin and the clay surface, i.e. the 'structure resembling effect'. This effect induces a change in the transition probabilities. † Electronic supplementary information (ESI) available: The structure of synthetic saponite (Fig. S1), the plot of (3 a /3 b ) C /(3 a /3 b ) W versus f C /f W for Sb V Pors (Fig. S2), and the section entitled "The synthesis of Sb V Pors" are available. See

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Section: Introductionmentioning

confidence: 99%

Structure resembling effect of clay surface on photochemical properties of meso-phenyl or pyridyl-substituted monocationic antimony(v) porphyrin derivatives

2015

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“…This unfavorable quenching process of the excited state is generally called “self-quenching”. Many researchers have been investigating the self-quenching for constructing efficient photochemical reaction systems. − However, since a self-quenching includes various types of possible mechanisms and we cannot distinguish them definitely, the mechanism of self-quenching has not been revealed entirely.…”

Section: Introductionmentioning

confidence: 99%

“…A self-quenching is a quenching process of excited state molecule due to an interaction between the same types of molecules. The mechanism of the interaction is classified into a static process and a dynamic process. − Under the static process, − an aggregation of molecules is the main factor to induce a self-quenching. Generally an aggregation is defined as an interaction between transition dipole moments of dyes.…”

Section: Introductionmentioning

confidence: 99%

Regulation of the Collisional Self-Quenching of Fluorescence in Clay/Porphyrin Complex by Strong Host–Guest Interaction

et al. 2012

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This paper proposes a novel methodology to improve noncollisional photochemical reactions such as Förster resonance energy transfer on solid surfaces. Since an excited guest molecule densely adsorbed on the solid surfaces is quenched by an unfavorable interaction between guests in general, the photochemical reactions such as electron and energy transfers tend to be inefficient compared to those in homogeneous systems. In this work, the mechanism of unfavorable quenching process of dyes on the clay surface as a typical solid surface for the photochemical energy transfer was systematically investigated by using a series of porphyrin derivatives. As a result, it was found that the quenching rate constants of excited guest dye determined by the time-resolved fluorescence measurements correlated well with the strengths of coulombic interaction between host and guest. The strong coulombic interaction should suppress the mobility and collision frequency of guests on the clay surface; thus, the collision of guest molecules was revealed as the origin of unfavorable quenching for photochemical reactions on the clay surface. According to this principle, we will be able to construct efficient photochemical reaction systems without any quenching process, such as efficient energy transfers toward an artificial light-harvesting system. In fact, we have already realized almost 100% energy transfer by the suppression of quenching process on the clay surface (e.g., J. Am. Chem. Soc.2011, 133, 14280-14286).

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“…As a result of the controlled distribution, which will be related to the efficiency of the excitation and stability of the excited states, and the access and diffusion of reactants and products, the efficiency of the reaction will be optimized. Taking these points into consideration, we have extended the host–guest systems composed of [Ru(bpy) 3 ] 2+ and mesoporous silicas using modified mesoporous silicas [ 187 – 190 ]. The surface density (or concentration) of the molecular catalyst ([Ru(bpy) 3 ] 2+ ) has been controlled within 0.8 μ mol m −2 mesopore surface or 1.0 mol L −1 mesopore pore volume not only by the varied loading of molecular catalyst but also by the surface density (or concentration) of immobilized functional unit (sulfonated phenyl group), which interacts with the molecular catalysts).…”

Section: Spatial Distribution (Location Density and Orientation) Of mentioning

confidence: 99%

Host–guest chemistry of mesoporous silicas: precise design of location, density and orientation of molecular guests in mesopores

Sohmiya

Saito

Ogawa

2015

Science and Technology of Advanced Materials

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Mesoporous solids, which were prepared from inorganic-surfactant mesostructured materials, have been investigated due to their very large surface area and high porosity, pore size uniformity and variation, periodic pore arrangement and possible pore surface modification. Morphosyntheses from macroscopic morphologies such as bulk monolith and films, to nanoscopic ones, nanoparticles and their stable suspension, make mesoporous materials more attractive for applications and detailed characterization. This class of materials has been studied for such applications as adsorbents and catalysts, and later on, for optical, electronic, environmental and bio-related ones. This review summarizes the studies on the chemistry of mesoporous silica and functional guest species (host–guest chemistry) to highlight the present status and future applications of the host–guest hybrids.

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Controlled spatial distribution of tris(2,2′-bipyridine)ruthenium cation ([Ru(bpy)3]2+) in aluminum containing mesoporous silicas

Cited by 15 publications

References 44 publications

Structure resembling effect of clay surface on photochemical properties of meso-phenyl or pyridyl-substituted monocationic antimony(v) porphyrin derivatives

Structure resembling effect of clay surface on photochemical properties of meso-phenyl or pyridyl-substituted monocationic antimony(v) porphyrin derivatives

Regulation of the Collisional Self-Quenching of Fluorescence in Clay/Porphyrin Complex by Strong Host–Guest Interaction

Host–guest chemistry of mesoporous silicas: precise design of location, density and orientation of molecular guests in mesopores

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