Zeolite-entrapped ruthenium(II) complexes with bipyridine and related ligands. Elimination of ligand-field-state deactivation and increase in 3MLCT state lifetimes

Maruszewski, K.; Strommen, Dennis P.; Kincaid, James R.

doi:10.1021/ja00071a049

Cited by 115 publications

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“…This conclusion was verified and led to the development of a reliable method for the preparation of pure samples of zeolite-entrapped [RuL 2 (H 2 O) 2 ] 2 (where L is a polypyridine ligand; see Equation (1)]. [13,14] This crude material can be purified in the same manner described for Z-[RuL 3 ] 2 complexes without generating significant amounts of the tris-ligated species.…”

Section: Zeolite Structuresmentioning

confidence: 89%

“…[13,14] Thus, both red and blue shifts in the l max and l em peaks were noted for various complexes and lifetimes were observed to either increase or decrease, dramatically so in certain cases. Based on thorough (temperature-dependent) lifetime and spectroscopic measurements of a rather extensive series of complexes, [13±18] a self-consistent and reliable framework has been devised for interpretation of these zeolite-induced alterations, the major effects being interactions of the polar zeolite framework with peripheral heteroatoms of ligands such as 2,2'-bipyrazine (bpz), and steric restrictions to elongation of the RuÀN bonds in the socalled ligand-field (LF), or 3 dd, state.…”

Section: Effects On Photophysical Propertiesmentioning

confidence: 95%

“…The availability of pure samples of zeolite-entrapped, bispolypyridine complexes provided an entry for the synthesis of tris-ligated heteroleptic complexes, according to the procedure in Equation (2), [13,14] where L and L' are two different polypyridine ligands.…”

Section: Zeolite Structuresmentioning

confidence: 99%

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The Development of Zeolite-Entrapped Organized Molecular Assemblies

Kincaid

2000

Chem. Eur. J.

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A brief summary is presented of the development of organized molecular assemblies entrapped within the supercages of Y-zeolite. Emphasis is placed on work originating in the author's laboratory, although a discussion of some of the important contributions made by other workers, which inspired and facilitated this work, are included. Following pioneering studies by Lunsford and co-workers, which demonstrated the feasibility of encapsulating the common photosensitizer [Ru(bpy)3]2+ within the Y-zeolite supercage, Dutta and co-workers documented efficient photoinduced electron transfer to viologen acceptors occupying neighboring supercages. We have extended the range of available materials by developing synthetically versatile methods to permit the incorporation of heteroleptic complexes, including constituent ligands which contain peripheral nitrogen donor groups; for example, 2,2'-bipyrazine. In an impressive study employing zeolite-excluded acceptors, Dutta and co-workers showed that the reducing equivalents available from photoinduced electron transfer from the zeolite entrapped sensitizer to intra-zeolite acceptors could be transferred to the extra-zeolite acceptors in aqueous suspensions, although the net charge-separation efficiency was low, presumably because of a persistent relatively efficient back-electron transfer process involving the primary photoproduct; that is, the entrapped sensitizer-acceptor dyad. Exploiting the susceptibility of certain heteroleptic complexes to add reactive ruthenium reagents, methods were developed to construct spatially organized donor-sensitizer-acceptor triads within the supercage framework of Y-zeolite. Such assemblies exhibit dramatically improved net charge-separation efficiencies, presumably as a consequence of inhibiting the wasteful back-electron transfer reaction between the initial sensitizer-acceptor couple.

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Section: Zeolite Structuresmentioning

confidence: 89%

Section: Effects On Photophysical Propertiesmentioning

confidence: 95%

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The Development of Zeolite-Entrapped Organized Molecular Assemblies

Kincaid

2000

Chem. Eur. J.

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“…Similar increases in this activation energy have been observed for Ru(bpy) 3 2 þ in solid-state media and attributed to destabilization of the ligand field states by the solid. 56 Interestingly, the fraction of cis-Ru(bpy) 2 (ina) 2 /TiO 2 excited states formed was also temperature dependent, behavior indicative of nonunity intersystem crossing yields. 55 In studies with compounds of the type Ru(ina)(NH 3 ) 5 2 þ and Ru(dcb)(NH 3 ) 4 2 þ , enhanced photostability after attachment to TiO 2 was also observed.…”

Section: Ligand Field and Ligand Localized Excited Statesmentioning

confidence: 97%

Solar Photochemistry with Transition Metal Compounds Anchored to Semiconductor Surfaces

Meyer

2010

Physical Inorganic Chemistry

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There exists a critical need for sustainable power on a terawatt (TW ¼ 10 12 W) scale. 1,2 As the world's need for energy is related to the number of people on Earth, a staggering 45% population growth over the last quarter-century equates to roughly 2 billion people and a 6 TW ($63%) increase in needed power. 3 In addition, the urbanism of third-world and industrialized nations and cities has led to an increase in the demand for fuel that has driven gas and oil prices to record highs. 3 Regardless of price, the continued use of fossil fuels cannot be a long-term solution as they come from a limited stock and the deleterious environmental consequences of their combustion have become self-evident. 4,5 The increased average global temperature and rates of glacial melting measured over the past few decades are telling signs. [6][7][8][9] Concern should be elicited as ice-core data correlate temperature with greenhouse gas concentrations over the past half-a-million years. The present 380 ppm atmospheric CO 2 levels exceed any values attained over the same time period. 5,6 Further, other than natural photosynthesis, there exist no obvious means by which we can decrease today's level. Thus, population, energy demand, and fuel prices do not convey the severity of the need for sustainable energy.It is our belief that molecular assemblies, particularly molecules arranged at semiconductor interfaces, will one day efficiently harvest and convert energy from the Sun, thereby providing sustainable, carbon-neutral power for future generations. The Sun is in fact the only source that on its own can provide the TWs of power needed. It has been shown that the amount of solar energy reaching the Earth in one day could power the planet for an entire year. 7,8 Remaining is the important challenge of harvesting, converting, and storing this energy in a cost-effective way. Coordination Physical Inorganic Chemistry: Reactions, Processes, and Applications Edited by Andreja Bakac

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“…The assembly of donor-acceptor pairs in heterogeneous support systems, such as zeolites, clays, and polymers, can provide the appropriate electrostatic and steric environment for the prevention of BeT, thereby favoring the generation of a long-lived charge-separated state. The study of zeolites as supramolecular scaffolds for energy storage systems (via long-lived charge separation) has been pioneered largely by Dutta et al [14,15,[73][74][75][76][77][78] with significant contributions also from the groups of Kincaid [79,80] and Mallouk [81][82][83]. There are many examples demonstrating how intelligent use of the zeolite framework, to spatially organize the donor and acceptor components, can result in the generation of extremely long-lived charge-separated states.…”

Section: Electron Transfermentioning

confidence: 99%

Supramolecular photochemistry in zeolites: From catalysts to sunscreens

Chrétien

2007

Pure and Applied Chemistry

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Zeolites are nanoporous, crystalline aluminosilicate materials comprised of a series of strictly uniform channels and cavities repeating along the tri-directional structure of the lattice. Over the last 30 years, researchers have increasingly recognized the desirable properties of these materials as hosts for photochemical reactions. This review will endeavor to draw attention to the properties of zeolite materials that make them appealing substrates for hosting guest molecules during photochemical reactions. An overview of some classical examples in zeolite host-guest photochemistry will be presented along with a brief description of a new use for zeolite materials as protective encapsulators.

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Zeolite-entrapped ruthenium(II) complexes with bipyridine and related ligands. Elimination of ligand-field-state deactivation and increase in 3MLCT state lifetimes

Cited by 115 publications

References 0 publications

The Development of Zeolite-Entrapped Organized Molecular Assemblies

The Development of Zeolite-Entrapped Organized Molecular Assemblies

Solar Photochemistry with Transition Metal Compounds Anchored to Semiconductor Surfaces

Supramolecular photochemistry in zeolites: From catalysts to sunscreens

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