scholarly journals Tunable Band Gaps in MUV-10(M): A Family of Photoredox-Active MOFs with Earth-Abundant Open Metal Sites

2021 ◽  
Author(s):  
Kevin Fabrizio ◽  
Konstantinos Lazarou ◽  
Lillian Payne ◽  
Liam Twight ◽  
Christopher H. Hendon ◽  
...  
Keyword(s):  
Band Gaps ◽  
Redox Potentials ◽  
Research Attention ◽  
Co Catalysts ◽  
Redox Indicators ◽  
Open Metal Sites ◽  
Earth Abundant ◽  
Metal Organic ◽  
Electrostatic Control

<div> <div> <p>Titanium-based metal—organic frameworks (Ti-MOFs) attract intense research attention because they can store charges in the form of Ti3+ and they serve as photosensitizers for co-catalysts through heterogeneous photoredox reactions at the MOF-liquid interface. Both charge storage and charge transfer depend on redox potentials of the MOF and the molecular substrate, but the factors controlling these energetic aspects are not well understood. Additionally, photocatalysis involving Ti-MOFs relies on co-catalysts rather than the intrinsic Ti reactivity in part because Ti-MOFs with open metal sites are rare. Here, we report that the class of Ti-MOFs known as MUV-10 can be synthetically modified to include a range of redox-inactive ions with flexible coordination environments that control the energies of the photoactive orbitals. Lewis acidic cations installed in the MOF cluster (Cd, Sr , and Ba ) or introduced to the pores (H, Li, Na, K) tune the electronic structure and band gaps of the MOFs. Through use of optical redox indicators, we report the first direct measurement of the Fermi levels (redox potentials) of photoexcited MOFs in situ. Taken together, these results explain the ability of Ti-MOFs to store charges and provide design principles for achieving heterogeneous photoredox chemistry with electrostatic control.</p> </div> </div>

scholarly journals Tunable Band Gaps in MUV-10(M): A Family of Photoredox-Active MOFs with Earth-Abundant Open Metal Sites

2021 ◽  
Author(s):  
Kevin Fabrizio ◽  
Konstantinos Lazarou ◽  
Lillian Payne ◽  
Liam Twight ◽  
Christopher H. Hendon ◽  
...  
Keyword(s):  
Band Gaps ◽  
Redox Potentials ◽  
Research Attention ◽  
Co Catalysts ◽  
Redox Indicators ◽  
Open Metal Sites ◽  
Earth Abundant ◽  
Metal Organic ◽  
Electrostatic Control

<div> <div> <p>Titanium-based metal—organic frameworks (Ti-MOFs) attract intense research attention because they can store charges in the form of Ti3+ and they serve as photosensitizers for co-catalysts through heterogeneous photoredox reactions at the MOF-liquid interface. Both charge storage and charge transfer depend on redox potentials of the MOF and the molecular substrate, but the factors controlling these energetic aspects are not well understood. Additionally, photocatalysis involving Ti-MOFs relies on co-catalysts rather than the intrinsic Ti reactivity in part because Ti-MOFs with open metal sites are rare. Here, we report that the class of Ti-MOFs known as MUV-10 can be synthetically modified to include a range of redox-inactive ions with flexible coordination environments that control the energies of the photoactive orbitals. Lewis acidic cations installed in the MOF cluster (Cd, Sr , and Ba ) or introduced to the pores (H, Li, Na, K) tune the electronic structure and band gaps of the MOFs. Through use of optical redox indicators, we report the first direct measurement of the Fermi levels (redox potentials) of photoexcited MOFs in situ. Taken together, these results explain the ability of Ti-MOFs to store charges and provide design principles for achieving heterogeneous photoredox chemistry with electrostatic control.</p> </div> </div>

scholarly journals Tunable Band Gaps in MUV-10(M): A Family of Photoredox-Active MOFs with Earth-Abundant Open Metal Sites

2021 ◽  
Author(s):  
Kevin Fabrizio ◽  
Konstantinos Lazarou ◽  
Lillian Payne ◽  
Liam Twight ◽  
Christopher H. Hendon ◽  
...  
Keyword(s):  
Band Gaps ◽  
Redox Potentials ◽  
Research Attention ◽  
Co Catalysts ◽  
Redox Indicators ◽  
Open Metal Sites ◽  
Earth Abundant ◽  
Metal Organic ◽  
Electrostatic Control

<div> <div> <div> <p>Titanium-based metal—organic frameworks (Ti-MOFs) attract intense research attention because they can store charges in the form of Ti3+ and they serve as photosensitizers for co-catalysts through heterogeneous photoredox reactions at the MOF-liquid interface. Both charge storage and charge transfer depend on redox potentials of the MOF and the molecular substrate, but the factors controlling these energetic aspects are not well understood. Additionally, photocatalysis involving Ti-MOFs relies on co-catalysts rather than the intrinsic Ti reactivity in part because Ti-MOFs with open metal sites are rare. Here, we report that the class of Ti-MOFs known as MUV-10 can be synthetically modified to include a range of redox-inactive ions with flexible coordination environments that control the energies of the photoactive orbitals. Lewis </p> <p>acidic cations installed in the MOF cluster (Cd, Sr , and Ba ) or introduced to the pores (H, Li, Na, K) tune the electronic structure and band gaps of the MOFs. Through use of optical redox indicators, we report the first direct measurement of the Fermi levels (redox potentials) of photoexcited MOFs in situ. Taken together, these results explain the ability of Ti-MOFs to store charges and provide design principles for achieving heterogeneous photoredox chemistry with electrostatic control.</p> </div> </div> </div>

Tunable Band Gaps in MUV-10(M): A Family of Photoredox-Active MOFs with Earth-Abundant Open Metal Sites

2021 ◽  
Author(s):  
Kevin Fabrizio ◽  
Konstantinos A. Lazarou ◽  
Lillian I. Payne ◽  
Liam P. Twight ◽  
Stephen Golledge ◽  
...  
Keyword(s):  
Band Gaps ◽  
Open Metal Sites ◽  
Earth Abundant

In situ synthesis of novel Cu2CO3(OH)2 decorated 2D TiO2 nanosheets with efficient photocatalytic H2 evolution activity

2018 ◽  
Vol 47 (2) ◽  
pp. 348-356 ◽  
Author(s):  
Hao Xu ◽  
Dongsheng Dai ◽  
Songsong Li ◽  
Lei Ge ◽  
Yangqin Gao
Keyword(s):  
Hydrogen Evolution ◽  
Low Cost ◽  
In Situ Synthesis ◽  
H2 Evolution ◽  
Photocatalytic Hydrogen Evolution ◽  
Co Catalysts ◽  
Tio2 Nanosheets ◽  
Earth Abundant ◽  
Photocatalytic H2 Evolution

Semiconductor-based photocatalytic hydrogen evolution from water with earth-abundant and low cost co-catalysts has attracted much attention.

Inquiry for the multifunctional design of metal–organic frameworks: in situ equipping additional open metal sites (OMSs) inducing high CO2 capture/conversion abilities

2021 ◽  
Author(s):  
Mingwei Jia ◽  
Jiantang Li ◽  
Jiaming Gu ◽  
Lirong Zhang ◽  
Yunling Liu
Keyword(s):  
Co2 Capture ◽  
Metal Organic Frameworks ◽  
High Co2 ◽  
Synergistic Catalysis ◽  
Open Metal Sites ◽  
Metal Organic ◽  
Multifunctional Design

On the basis of in situ fabricating multifunctional MOFs, a binuclear Co-MOF with open cobalt sites was accomplished. The multifunctional sites afforded increased CO2 uptake, together with the synergistic catalysis in promoting the CO2 conversion.

Tuning the Redox Activity of Metal−Organic Frameworks for Enhanced, Selective O2 Binding

2019 ◽  
Author(s):  
Andrew Rosen ◽  
M. Rasel Mian ◽  
Timur Islamoglu ◽  
Haoyuan Chen ◽  
Omar Farha ◽  
...  
Keyword(s):  
Density Functional ◽  
Metal Organic Frameworks ◽  
Redox Activity ◽  
Screening Methods ◽  
Bridging Ligands ◽  
Metal Centers ◽  
Computational Screening ◽  
Open Metal Sites ◽  
Metal Organic ◽  
Unsaturated Metal Sites

<p>Metal−organic frameworks (MOFs) with coordinatively unsaturated metal sites are appealing as adsorbent materials due to their tunable functionality and ability to selectively bind small molecules. Through the use of computational screening methods based on periodic density functional theory, we investigate O<sub>2</sub> and N<sub>2</sub> adsorption at the coordinatively unsaturated metal sites of several MOF families. A variety of design handles are identified that can be used to modify the redox activity of the metal centers, including changing the functionalization of the linkers (replacing oxido donors with sulfido donors), anion exchange of bridging ligands (considering μ-Br<sup>-</sup>, μ-Cl<sup>-</sup>, μ-F<sup>-</sup>, μ-SH<sup>-</sup>, or μ-OH<sup>-</sup> groups), and altering the formal oxidation state of the metal. As a result, we show that it is possible to tune the O<sub>2</sub> affinity at the open metal sites of MOFs for applications involving the strong and/or selective binding of O<sub>2</sub>. In contrast with O<sub>2</sub> adsorption, N<sub>2</sub> adsorption at open metal sites is predicted to be relatively weak across the MOF dataset, with the exception of MOFs containing synthetically elusive V<sup>2+</sup> open metal sites. As one example from the screening study, we predict that exchanging the μ-Cl<sup>-</sup> ligands of M<sub>2</sub>Cl<sub>2</sub>(BBTA) (H<sub>2</sub>BBTA = 1<i>H</i>,5<i>H</i>-benzo(1,2-d:4,5-d′)bistriazole) with μ-OH<sup>-</sup> groups would significantly enhance the strength of O<sub>2</sub> adsorption at the open metal sites without a corresponding increase in the N<sub>2</sub> affinity. Experimental investigation of Co<sub>2</sub>Cl<sub>2</sub>(BBTA) and Co<sub>2</sub>(OH)<sub>2</sub>(BBTA) confirms that the former exhibits only weak physisorption, whereas the latter is capable of chemisorbing O<sub>2</sub> at room temperature. The chemisorption behavior is attributed to the greater electron-donating character of the μ-OH<sup>-</sup><sub> </sub>ligands and the presence of H-bonding interactions between the μ-OH<sup>-</sup> bridging ligands and the O<sub>2</sub> adsorbate.</p>

Mechanistische Untersuchungen zum reversiblen Gleichgewicht von metallorganischen Tripeldecker- und Sandwichkomplexen des Typs [Bis{(η5-CpR)Co}-μ-{η4:η4-aren}] und [(η5-CpR)Co(η6-aren)] / Mechanistic Studies towards the Reversible Equilibrium between Metal Organic Triple Decker and Sandwich Complexes [Bis{(η5 -CpR)Co}-μ-{η4 :η4-arene}] and [{(η5-CpR)Co(η6-arene)]

1998 ◽  
Vol 53 (11) ◽  
pp. 1267-1272 ◽  
Author(s):  
Jörg J. Schneider ◽  
Dirk Wolf
Keyword(s):  
Ligand Exchange ◽  
Sandwich Complexes ◽  
Valuable Metal ◽  
H Nmr ◽  
Synthetic Utility ◽  
Metal Organic ◽  
Arene Ligand ◽  
Benzene Toluene

The arene ligand exchange mechanism of slipped arene triple deckers [Bis{(η5-CpR)Co}-μ-{η4:η4-arene}] (R = Me5, 1,2,4 tri-tert butyl, arene = benzene, toluene) 1 was studied by 1H-NMR spectroscopy for different concentrations and solvents. It has been found that triple deckers of type 1 decompose slowly in solution. A unique equilibrium, between these triple deckers and the mixed sandwich complexes [(η6-arene)Co(η5-CpR)] and 14 e [(η5-Cp)Co]solv fragments generated in situ by decomposition o f 1 exists. In addition to this equilibrium arene lability of the thus formed mixed sandwich complex type has been detected by NMR making slipped triple deckers 1 ideal single source compounds for the generation of two [(η5-Cp)Co] fragments in one reaction step. Such fragments are valuable metal ligand components with high synthetic utility in organometallic chemistry.

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