An official website of the United States government
Abstract Shewanella oneidensisMR‐1 is a promising chassis organism for microbial electrosynthesis because it has a well‐defined biochemical pathway (the Mtr pathway) that can connect extracellular electrodes to respiratory electron carriers inside the cell. We previously found that the Mtr pathway can be used to transfer electrons from a cathode to intracellular electron carriers and drive reduction reactions. In this work, we hypothesized that native NADH dehydrogenases form an essential link between the Mtr pathway and NADH in the cytoplasm. To test this hypothesis, we compared the ability of various mutant strains to accept electrons from a cathode and transfer them to an NADH‐dependent reaction in the cytoplasm, reduction of acetoin to 2,3‐butanediol. We found that deletion of genes encoding NADH dehydrogenases from the genome blocked electron transfer from a cathode to NADH in the cytoplasm, preventing the conversion of acetoin to 2,3‐butanediol. However, electron transfer to fumarate was not blocked by the gene deletions, indicating that NADH dehydrogenase deletion specifically impacted NADH generation and did not cause a general defect in extracellular electron transfer. Proton motive force (PMF) is linked to the function of the NADH dehydrogenases. We added a protonophore to collapse PMF and observed that it blocked inward electron transfer to acetoin but not fumarate. Together these results indicate a link between the Mtr pathway and intracellular NADH. Future work to optimize microbial electrosynthesis inS. oneidensisMR‐1 should focus on optimizing flux through NADH dehydrogenases.
more »
« less
Multielectron C–H photoactivation with an Sb( v ) oxo corrole
Pnictogen complexes are ideal for mediating multi-electron chemical reactions in two-electron steps. We report an Sb( v ) bis-μ-oxo corrole that photochemically oxidises the C–H bonds of organic substrates. In the case of toluene, the substrate is oxidised to benzaldehyde, a rare example of a four-electron photoreaction.
more »
« less
- Award ID(s):
- 1855531
- PAR ID:
- 10180796
- Date Published:
- Journal Name:
- Chemical Communications
- Volume:
- 56
- Issue:
- 39
- ISSN:
- 1359-7345
- Page Range / eLocation ID:
- 5247 to 5250
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
New coordination environments are reported for Np( iii ) and Pu( iii ) based on pilot studies of U( iii ) in 2.2.2-cryptand (crypt). The U( iii )-in-crypt complex, [U(crypt)I 2 ][I], obtained from the reaction between UI 3 and crypt, is treated with Me 3 SiOTf (OTf = O 3 SCF 3 ) in benzene to form the [U(crypt)(OTf) 2 ][OTf] complex. Similarly, the isomorphous Np( iii ) and Pu( iii ) complexes were obtained similarly starting from [AnI 3 (THF) 4 ]. All three complexes (1-An; An = U, Np, Pu) contain an encapsulated actinide in a THF-soluble complex. Absorption spectroscopy and DFT calculations are consistent with 5f 3 U( iii ), 5f 4 Np( iii ), and 5f 5 Pu( iii ) electron configurations.more » « less
-
Abstract In this work, the Coulson‐Longuet‐Higgins response function (atom‐atomic polarizabilities [AAPs]) is used to describe the transfer of an electron perturbation in π‐conjugated systems in the presence of a static electric field. Computations are performed using different many‐electron approaches to study the effect. An accurate account of the electron correlation is shown to play a key role in the description of the interaction of a π‐shell with the external electrostatic field. Studies in this work reveal that the Hückel theory widely used in calculations of electron‐perturbation transfer is not reliable even at the qualitative level to describe the effects studies in this work. However, the π‐electron coupled cluster theory has been proven capable of providing a reliable electronic structure (among them, AAPs and excitation energies) that agree with the results obtained with the π‐electron full configuration‐interaction approach. The calculations also show that these properties have an essentially nonlinear character in terms of the strength of the applied electric field. The results obtained in the present work can provide useful information relevant to the application of π‐conjugated systems in molecular electronics.more » « less
-
Abstract In this work, an electron blocking layer (EBL) free light emitting diode (LED) nanowire is proposed with alternate prestrained layers of InxGa1−xN/GaN, which are inserted between the GaN/InGaN multi‐quantum wells (MQWs) and n‐GaN layer. This study signifies the role of prestrained layers on the piezoelectric polarization of LED nanowires, for enhanced luminescence. When compared with the conventional one, the EBL free LED nanowire with prestrained layer shows an enhancement of ~2.897% efficiency, which occurs due to the reduction of polarization field in the active region. The LED with 15% indium in the prestrained layer obtains a maximum efficiency of 85.21% along with a minimum efficiency droop of 3.848% at 40 mA injected current. The proposed III‐nitride LED nanostructure allows for achieving superior optical power across the output spectral range.more » « less
- Free Publicly Accessible Full Text
-
Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1039/c9cc09892e
