Light Harvesting by a Periodic Mesoporous Organosilica Chromophore

Inagaki, Shigenori; Ohtani, Osamu; Goto, Yasutomo; Okamoto, Ken‐ichi; Ikai, Masamichi; Yamanaka, Kenichi; Tani, Takao; Okada, Tadashi

doi:10.1002/ange.200900266

Cited by 63 publications

(69 citation statements)

References 39 publications

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“…The almost complete quenching of the emission from the PPy moieties at 420 nm for Ir-PPy-PMO suggests efficient energy transfer from the PPy moieties to the [Ir III (ppy) 3 ] complex. The system presented is the first lightharvesting system for energy funneling into the acceptor (Ir complex) located on the pore walls, although we reported some PMO-based light-harvesting systems, in which acceptors such as dye molecules [18,19] and rhenium complexes [20] are placed in the mesochannels. Ru-PPy-PMO showed almost no emission because of the very low luminescence quantum yield of [Ru II (bpy) 2 (ppy)] + .…”

Section: Methodsmentioning

confidence: 99%

Periodic Mesoporous Organosilica Derivatives Bearing a High Density of Metal Complexes on Pore Surfaces

Waki¹,

Mizoshita²,

Tani³

et al. 2011

Angewandte Chemie

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Periodic mesoporous organosilicas (PMOs) synthesized from alkoxysilane precursors bridged with organic moieties, R[Si-(OR') 3 ] n , n ! 2, R = organic group, R' = CH 3 , C 2 H 5 , etc. by surfactant-directed self-assembly are a new class of functional materials that have well-defined nanoporous structures and highly functional organic groups in the silica walls. [1] It is preferable to incorporate organic groups in the pore walls rather than to graft them on the wall surfaces because in the former case the organic groups offer little resistance to the diffusion of molecules and ions in the mesochannels and are quite resistant to leaching. Many PMOs containing bridging organic groups (R) that range from aliphatic and aromatic hydrocarbons to heterocycles and metal complexes have been reported. [2,3] Incorporating metal complexes into PMO frameworks is particularly important because metal complexes possess unique features such as catalytic activity, luminescence emission, redox properties, and excited-state reactivity. [4] PMOs with metal complexes are usually prepared by co-condensation of a metal-complex-bridged alkoxysilane precursor and a large amount (typically over 90 %) of tetraethoxysilane. This is due to general difficulties in producing PMOs from just a precursor with a bulky metal complex because of weak interaction between hydrolyzed precursors and surfactants. [5] An alternative approach is to form metal complexes on a pore surface after synthesis by using bridging organic groups in the framework as metal ligands. Matsuoka and co-workers attached the organometallic fragments {Cr(CO) 3 } and {Mo(CO) 3 } to the phenyl ring of phenylene(Ph)-bridged PMO. [6] Recently, Polarz and co-workers reported the coordination of transition-metal cations to Ph-PMOs functionalized with carboxylic, dithiocarboxylic, acetylacetonate, and amine groups. [7] This approach has the advantage that bulky metal complexes can be densely and selectively integrated on the pore surface of highly ordered PMOs. However, these metal complexes attached to a PMO framework have limited functionalities mainly because of the poor ligand ability of these PMOs.Recently, octahedral d 6 metal complexes such as polypyridine-coordinated ruthenium (Ru II ) and iridium (Ir III ) com-

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Section: Methodsmentioning

confidence: 99%

Periodic Mesoporous Organosilica Derivatives Bearing a High Density of Metal Complexes on Pore Surfaces

Waki¹,

Mizoshita²,

Tani³

et al. 2011

Angewandte Chemie

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“…Our model system, benzene PMO, is chosen as it is structurally the simplest of aromatic PMOs, which have been shown to self-organize at a molecular scale [25] and possess optical [26] and electrical [27] properties that promise applications in light-harvesting [28,29], photocatalysis, and photovoltaics. Specifically, we show that methanol is a better solvent in synthesizing thin films of benzene PMO through EISA, whereas ethanol favors the formation of crystals of hydrolyzed organosilica precursor.…”

Section: Introductionmentioning

confidence: 99%

The effect of solvent in evaporation-induced self-assembly: A case study of benzene periodic mesoporous organosilica

et al. 2011

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Volatile organic solvents were considered to have little influence on the synthesis of mesostructured materials through evaporation-induced self-assembly (EISA), because upon evaporation they leave the sol and hence do not interfere with the self-assembly process. We show here that the choice of solvent is crucial in the synthesis of thin films of phenylene-bridged periodic mesoporous organosilica (benzene PMO). Methanol is found to be a better solvent for the synthesis of thin films, whereas ethanol favors the formation of (HO) 3 Si-C 6 H 4 -Si(OH) 3 crystals, the identity and structure of which is established by X-ray diffraction. A ternary reactant composition diagram is designed to visualize the relationship among multiple synthesis experiments and to guide the interpretation of experimental results and optimization of the quality of the periodic mesoporous organosilica film. Our study highlights the importance of solvent choice, a factor often neglected in EISA. We expect it to inspire researchers to explore the effect of solvent in designing the synthesis of mesoporous materials. mesoporous materials, periodic mesoporous organosilica, evaporation induced self assembly, thin films

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“…The emission at 550 nm from [Ir III (ppy) 3 ] was greater for excitation at 300 nm than at 380 nm, as shown in Figure 2 c. This result is thought to be caused by the more 3 ] complex. The system presented is the first lightharvesting system for energy funneling into the acceptor (Ir complex) located on the pore walls, although we reported some PMO-based light-harvesting systems, in which acceptors such as dye molecules [18,19] and rhenium complexes [20] are placed in the mesochannels. Ru-PPy-PMO showed almost no emission because of the very low luminescence quantum yield of [Ru II (bpy) Figure 2 a and d).…”

mentioning

confidence: 97%

Periodic Mesoporous Organosilica Derivatives Bearing a High Density of Metal Complexes on Pore Surfaces

Waki¹,

Mizoshita²,

Tani³

et al. 2011

Angew Chem Int Ed

Self Cite

View full text Add to dashboard Cite

Periodic mesoporous organosilicas (PMOs) synthesized from alkoxysilane precursors bridged with organic moieties, R[Si-(OR') 3 ] n , n ! 2, R = organic group, R' = CH 3 , C 2 H 5 , etc. by surfactant-directed self-assembly are a new class of functional materials that have well-defined nanoporous structures and highly functional organic groups in the silica walls.[1] It is preferable to incorporate organic groups in the pore walls rather than to graft them on the wall surfaces because in the former case the organic groups offer little resistance to the diffusion of molecules and ions in the mesochannels and are quite resistant to leaching. Many PMOs containing bridging organic groups (R) that range from aliphatic and aromatic hydrocarbons to heterocycles and metal complexes have been reported. [2,3] Incorporating metal complexes into PMO frameworks is particularly important because metal complexes possess unique features such as catalytic activity, luminescence emission, redox properties, and excited-state reactivity. [4] PMOs with metal complexes are usually prepared by co-condensation of a metal-complex-bridged alkoxysilane precursor and a large amount (typically over 90 %) of tetraethoxysilane. This is due to general difficulties in producing PMOs from just a precursor with a bulky metal complex because of weak interaction between hydrolyzed precursors and surfactants. [5] An alternative approach is to form metal complexes on a pore surface after synthesis by using bridging organic groups in the framework as metal ligands. Matsuoka and co-workers attached the organometallic fragments {Cr(CO) 3 } and {Mo(CO) 3 } to the phenyl ring of phenylene(Ph)-bridged PMO.[6] Recently, Polarz and co-workers reported the coordination of transition-metal cations to Ph-PMOs functionalized with carboxylic, dithiocarboxylic, acetylacetonate, and amine groups. [7] This approach has the advantage that bulky metal complexes can be densely and selectively integrated on the pore surface of highly ordered PMOs. However, these metal complexes attached to a PMO framework have limited functionalities mainly because of the poor ligand ability of these PMOs.Recently, octahedral d 6 metal complexes such as polypyridine-coordinated ruthenium (Ru II ) and iridium (Ir III ) complexes have been attracting interest because of their photophysical properties and they have been widely utilized for dye-sensitized solar cells, [8] organic light emitting devices, [9] and photocatalysts.[10] Typical ligands for the d 6 metal complexes are bipyridine and 2-phenylpyridine (PPy).[11] Thus, the synthesis of PMO containing such chelating ligands in the framework is important for the formation of highly functional d 6 metal complexes on the pore surface. Herein, we report the synthesis of a novel PMO containing PPy moieties in the PMO framework (PPy-PMO) and the successful formation of a high density of Ru or Ir polypyridine complexes on the pore surfaces (Scheme 1). The PPy ligands in the pore walls of the obtained PPy-PMOs exhibit molecular-scale periodi...

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Light Harvesting by a Periodic Mesoporous Organosilica Chromophore

Cited by 63 publications

References 39 publications

Periodic Mesoporous Organosilica Derivatives Bearing a High Density of Metal Complexes on Pore Surfaces

Periodic Mesoporous Organosilica Derivatives Bearing a High Density of Metal Complexes on Pore Surfaces

The effect of solvent in evaporation-induced self-assembly: A case study of benzene periodic mesoporous organosilica

Periodic Mesoporous Organosilica Derivatives Bearing a High Density of Metal Complexes on Pore Surfaces

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