Solid-state organometallic chemistry of molecular metal oxide clusters: carbon-hydrogen activation by an iridium polyoxometalate

Siedle, A. R.; Newmark, Richard A.; Brown-Wensley, K. A.; Skarjune, R. P.; Haddad, L. C.; Hodgson, Keith O.; Roe, A. L.

doi:10.1021/om00099a037

Cited by 27 publications

(12 citation statements)

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“…2.15(2)–2.29(3) Å]. Thus, although the gross structure is unambiguous in showing a single C 3 fragment bound to the metal center, whether it is an η 2 -bound propene with a supporting γ-agostic 93 interaction ( I , Scheme 7 ) or the isomeric allyl-hydride, that arises from γ-C–H activation of propene ( II ), 22 , 49 , 94 – 97 cannot be determined due to the quality of the data. We thus turned to variable temperature SSNMR and solution NMR spectroscopy, as well as periodic DFT calculations, to determine the precise structure.…”

Section: Resultsmentioning

confidence: 99%

“… 24 This rapid catalytic solid/gas H/D scrambling in 3,3,3-d 3 -propene using [1-NBA][BAr F 4 ] can be compared to that measured in solution phase under stoichiometric conditions for Ir(POCOP t Bu )(η 2 -d 3 -propene) that requires heating (∼40 h at 333 K), 22 or the slow (greater than 16 h) solid/gas reactivity of [(Ph 3 P) 3 IrH 2 ] 3 [PW 12 O 40 ] with 3,3,3-d 3 -propene that results in intramolecular scrambling in the final allyl-hydride product. 49 Interestingly, that this solid/gas catalysis is much faster (∼5 minutes) compared with bulk-scale synthesis of [1-(propene)][BAr F 4 ] (2 h) suggests that the most active sites are at, or near, the surface. We have previously drawn similar conclusions regarding the use of [Rh( i Bu 2 PCH 2 CH 2 P i Bu 2 )(η 2 η 2 -C 4 H 6 )][BAr F 4 ] as a solid-state ethene hydrogenation catalyst.…”

Section: Resultsmentioning

confidence: 99%

“…Experimental evidence points towards a presumed molecular species as the active catalyst, although the precise details have not been disclosed. Siedle & Newmark reported the room temperature solid/gas isomerization of simple alkenes using iridium or rhodium phosphine cations partnered with Keggin-type trianions, such as [Ir(H) 2 (PPh 3 ) 2 ] 3 [PW 12 O 40 ], 47 – 49 however the precise molecular structure of the catalyst was not determined.…”

Section: Introductionmentioning

confidence: 99%

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Solid-state molecular organometallic chemistry. Single-crystal to single-crystal reactivity and catalysis with light hydrocarbon substrates

et al. 2017

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Solid-state molecular organometallic chemistry. Single-crystal to single-crystal reactivity and catalysis with light hydrocarbon substrates

et al. 2017

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“…This is mainly due to formation of polyoxometalates between the transition metals and other ions in the chemical bath. The valence electrons that otherwise would be donated to the material are instead localized into formed complexes [39], which limit the doping efficiencies to ~1 donated electron per ion. This phenomenon is observed even in the materials with upward of seven valence electrons [37,38].…”

Section: Cbd Experimental Datamentioning

confidence: 99%

Efficient Optimization of the Optoelectronic Performance in Chemically Deposited Thin Films

Slonopas¹,

Dhar²,

Ryan³

et al. 2017

Thin Film Processes - Artifacts on Surface Phenomena and Technological Facets

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Chemical deposition methodology is a well-understood and highly documented category of deposition techniques. In recent years, chemical bath deposition (CBD) and chemical vapor deposition (CVD) have garnered considerable attention as an effective alternative to other deposition methods. The applicability of CVD and CBD for industrial-sized operations is perhaps the most attractive aspect, in that thin-film deposition costs inversely scale with the processing batch size without loss of desirable optoelectronic properties in the materials. A downside of the method is that the optoelectronic characteristics of these films are highly susceptible to spurious deposition growth mechanisms. For example, increasing the temperature of the chemical deposition bath can shift the deposition mechanisms from ion-by-ion (two dimensional) precipitation to bulk solution cluster-by-cluster (three dimensional) formation which then deposit. This drastically changes the structural, optical, and electrical characteristics of CBD-deposited thin films.A similar phenomenon is observed in CVD deposited materials. Thus, it is of great interest to study the coupling between the deposition parameters and subsequent effects on film performance. Such studies have been conducted to elucidate the correlation between growth mechanisms and film performance. Here, we present a review of the current literature demonstrating that simple changes can be made in processing conditions to optimize the characteristics of these films for optoelectronic applications.

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“…Doping efficiency was estimated for the T = 300K using [173][174]. The lower than expected doping efficiency is partially affected by the localization of nearly all iridium free electrons into the polyoxometalate formations [175].…”

Section: Iridium Doping Efficiencymentioning

confidence: 99%

Mid-IR Range Photosensitive Device Based on Chemically Deposited Nanocrystalline Chalcogenide Thin Films with Tunable Opto-electrical properties

Slonopas

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Past several decades have driven modernization of technology and machinery. This modernization has pushed the limits of our technology and increased our dependence on the energy. Additional side-effect of this rapid growth has been an exponential increase in the generated heat of the modern machinery.In most cases this waste heat is simply released into the environment. Numerous research groups have pursued an idea of capturing and converting the waste heat. Thermoelectric, pyroelectrics, organic Rankine cycle (ORC), and several other methods have been proposed to capture and convert the waste heat into electricity. Presently, all methods, however, have low conversion efficiency and are not economically feasible.In this work we focused on a practical approach to convert mid-IR electromagnetic waves to electricity. It is based on inexpensive thin film technology utilizing a junction between a narrow bandgap lead salt and wide bandgap chalcogenide film.Lead sulfide (PbS) was chosen as the narrow band semiconductors for the IR energy conversion.Lead salt photodetectors uniquely demonstrate high room temperature sensitivity to black-body sources in low temperatures and high internal quantum efficiency (QE). Further, the peculiar band structure of the lead salt allows for small Auger recombination and minimized losses.Due to its favorable opto-electrical properties and band compatibility with PbS, cadmium sulfide (CdS) was chosen as the wide bandgap semiconductor for this work.This work has shown that high quality nanocrystalline thin films of lead sulfide (PbS) and cadmium sulfide (CdS) can be grown cost efficiently using chemical bath deposition (CBD) method. Chemical bath seeding procedure was also developed in order to achieve reproducibility in the transport phenomena of the advanced materials. Seeding also allows these films to be deposited on any surface, including smooth flexible materials. Seeded kernels have shown to become the crystallization centers for both nanocrystalline films.Opto-electrical properties of the films were tuned in such a way to make the materials useful in a broad-band of the IR spectrum. We have shown that altering the parameters of the chemical bath deposition alters the grains hence changing the transport characteristics of the materials. We have shown that parameters of the chemical bath deposition can be optimized to produce highly sensitive thin films tuned to a specific range of the electromagnetic spectra.Novel transparent conducting oxide, Iridium (Ir) doped Titanium Oxide (TiO2) was developed in this work for the use in the optoelectronic device. Ir has been shown to be one of the most efficient dopants in thin films. Ir doped TiO2 has shown to have transport characteristics similar ii to those of the commonly used TCOs, with much higher optical transmittance in the infra-red range.Lastly devices were manufactured from the developed materials. TiO2/CdS/PbS/Au heterojunctions were manufactured and showed photoresponsivity. Device efficiencies were shown to depend on the...

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Solid-state organometallic chemistry of molecular metal oxide clusters: carbon-hydrogen activation by an iridium polyoxometalate

Cited by 27 publications

References 0 publications

Solid-state molecular organometallic chemistry. Single-crystal to single-crystal reactivity and catalysis with light hydrocarbon substrates

Solid-state molecular organometallic chemistry. Single-crystal to single-crystal reactivity and catalysis with light hydrocarbon substrates

Efficient Optimization of the Optoelectronic Performance in Chemically Deposited Thin Films

Mid-IR Range Photosensitive Device Based on Chemically Deposited Nanocrystalline Chalcogenide Thin Films with Tunable Opto-electrical properties

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