How CuCl and CuCl2 Insert into C–N Bonds of Diazo Compounds: An Electronic Structure and Mechanistic Study

2020 ◽  
Vol 124 (10) ◽  
pp. 2029-2035 ◽  
Author(s):  
Fengyu Li ◽  
John Zenghui Zhang ◽  
Fei Xia
Keyword(s):  
Electronic Structure ◽  
Diazo Compounds ◽  
Mechanistic Study

scholarly journals Tuning Rh(II)-Catalyzed Cyclopropanation with Tethered Thioether Ligands

2020 ◽  
Author(s):  
Derek Cressy ◽  
Cristian Zavala ◽  
Anthony Abshire ◽  
William Sheffield ◽  
Ampofo Darko
Keyword(s):  
Electronic Structure ◽  
Computational Modeling ◽  
Spectroscopic Investigation ◽  
Product Formation ◽  
Side Product ◽  
Diazo Compounds ◽  
Paddlewheel Complexes ◽  
Ethyl Diazoacetate ◽  
High Utility

Dirhodium(II) paddlewheel complexes have high utility in diazo-mediated cyclopropanation reactions and ethyl diazoacetate is one of the most commonly used diazo compounds in this reaction. In this study, we report our efforts to use tethered thioether ligands to tune the reactivity of Rh-carbene mediated cyclopropanation of olefins with ethyl diazoacetate. Microwave methods enabled the synthesis of a family of Rh-complexes in which tethered thioether moieties were coordinated to axial sites of the complex. Different tether lengths and thioether substituents were screened to optimize cyclopropane yeilds and minimize side product formation. Furthermore, good yields were obtained when equimolar diazo and olefin were used. Structural and spectroscopic investigation revealed that tethered thioethers changed the electronic structure of the rhodium core, which was instrumental in the performance of the catalysts. Computational modeling of the catalysts provided further support that the tethered thioethers were responsible for increased yields.

Mechanistic study on gold(I)-catalyzed crosscoupling of diazo compounds: A DFT study

2017 ◽  
Vol 118 (14) ◽  
pp. e25581
Author(s):  
Yan Li ◽  
Ruixue Tian ◽  
Changhai Liang
Keyword(s):  
Dft Study ◽  
Diazo Compounds ◽  
Mechanistic Study

In situ growth of Fe(ii)-MOF-74 nanoarrays on nickel foam as an efficient electrocatalytic electrode for water oxidation: a mechanistic study on valence engineering

2019 ◽  
Vol 55 (75) ◽  
pp. 11307-11310 ◽  
Author(s):  
Qijun Wang ◽  
Feifei Wei ◽  
Devaraj Manoj ◽  
Zheye Zhang ◽  
Junwu Xiao ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Water Oxidation ◽  
Nickel Foam ◽  
Mechanistic Study ◽  
In Situ Growth

DFT results first demonstrate that varying the metal valence can tune the stable intrinsic electronic structure of MOF, different valence Fe(ii) and Fe(iii)-MOF-74 nanoarrrays on nickel foam are further synthesized as electrode for water oxidation.

scholarly journals Tuning Rh(II)-Catalyzed Cyclopropanation with Tethered Thioether Ligands

2020 ◽  
Author(s):  
Derek Cressy ◽  
Cristian Zavala ◽  
Anthony Abshire ◽  
William Sheffield ◽  
Ampofo Darko
Keyword(s):  
Electronic Structure ◽  
Computational Modeling ◽  
Spectroscopic Investigation ◽  
Product Formation ◽  
Side Product ◽  
Diazo Compounds ◽  
Paddlewheel Complexes ◽  
Ethyl Diazoacetate ◽  
High Utility

Dirhodium(II) paddlewheel complexes have high utility in diazo-mediated cyclopropanation reactions and ethyl diazoacetate is one of the most commonly used diazo compounds in this reaction. In this study, we report our efforts to use tethered thioether ligands to tune the reactivity of Rh-carbene mediated cyclopropanation of olefins with ethyl diazoacetate. Microwave methods enabled the synthesis of a family of Rh-complexes in which tethered thioether moieties were coordinated to axial sites of the complex. Different tether lengths and thioether substituents were screened to optimize cyclopropane yeilds and minimize side product formation. Furthermore, good yields were obtained when equimolar diazo and olefin were used. Structural and spectroscopic investigation revealed that tethered thioethers changed the electronic structure of the rhodium core, which was instrumental in the performance of the catalysts. Computational modeling of the catalysts provided further support that the tethered thioethers were responsible for increased yields.

scholarly journals Lithium Attachment to C60 and Nitrogen- and Boron-Doped C60: A Mechanistic Study

Materials ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2136 ◽  
Author(s):  
Yingqian Chen ◽  
Chae-Ryong Cho ◽  
Sergei Manzhos
Keyword(s):  
Electronic Structure ◽  
Small Molecules ◽  
Lithium Ion ◽  
Single Atom ◽  
Mechanistic Study ◽  
Hybrid Functional ◽  
Generalized Gradient ◽  
Generalized Gradient Approximation ◽  
Boron Doped ◽  
P Type

Fullerene-based materials including C60 and doped C60 have previously been proposed as anodes for lithium ion batteries. It was also shown earlier that n- and p-doping of small molecules can substantially increase voltages and specific capacities. Here, we study ab initio the attachment of multiple lithium atoms to C60, nitrogen-doped C60 (n-type), and boron doped C60 (p-type). We relate the observed attachment energies (which determine the voltage) to changes in the electronic structure induced by Li attachment and by doping. We compare results with a GGA (generalized gradient approximation) functional and a hybrid functional and show that while they agree semi-quantitatively with respect to the expected voltages, there are qualitative differences in the electronic structure. We show that, contrary to small molecules, single atom n- and p-doping will not lead to practically useful modulation of the voltage–capacity curve beyond the initial stages of lithiation.

EELS Measurement of the Local Electronic Structure of Copper Atoms Segregated to Aluminum Grain Boundaries

1996 ◽  
Vol 54 ◽  
pp. 342-343
Author(s):  
S.J. Splinter ◽  
J. Bruley ◽  
P.E. Batson ◽  
D.A. Smith ◽  
R. Rosenberg
Keyword(s):  
Electronic Structure ◽  
Grain Boundaries ◽  
Boundary Segregation ◽  
Thin Layers ◽  
Nominal Composition ◽  
Spatially Resolved ◽  
Service Lifetime ◽  
Heat Treated ◽  
Probe Size ◽  
Local Electronic Structure

It has long been known that the addition of Cu to Al interconnects improves the resistance to electromigration failure. It is generally accepted that this improvement is the result of Cu segregation to Al grain boundaries. The exact mechanism by which segregated Cu increases service lifetime is not understood, although it has been suggested that the formation of thin layers of θ-CuA12 (or some metastable substoichiometric precursor, θ’ or θ”) at the boundaries may be necessary. This paper reports measurements of the local electronic structure of Cu atoms segregated to Al grain boundaries using spatially resolved EELS in a UHV STEM. It is shown that segregated Cu exists in a chemical environment similar to that of Cu atoms in bulk θ-phase precipitates.Films of 100 nm thickness and nominal composition Al-2.5wt%Cu were deposited by sputtering from alloy targets onto NaCl substrates. The samples were solution heat treated at 748K for 30 min and aged at 523K for 4 h to promote equilibrium grain boundary segregation. EELS measurements were made using a Gatan 666 PEELS spectrometer interfaced to a VG HB501 STEM operating at 100 keV. The probe size was estimated to be 1 nm FWHM. Grain boundaries with the narrowest projected width were chosen for analysis. EDX measurements of Cu segregation were made using a VG HB603 STEM.

Electronic structure studies of conducting polymers by electron energy-loss spectroscopy

1996 ◽  
Vol 54 ◽  
pp. 160-161
Author(s):  
J. Fink
Keyword(s):  
Electronic Structure ◽  
Conducting Polymers ◽  
Conjugated Polymers ◽  
Electron Acceptors ◽  
Electron Donors ◽  
Light Emitting ◽  
One Dimensional ◽  
New Class ◽  
Electrical Conductivities ◽  
Electron Energy Loss

Conducting polymers comprises a new class of materials achieving electrical conductivities which rival those of the best metals. The parent compounds (conjugated polymers) are quasi-one-dimensional semiconductors. These polymers can be doped by electron acceptors or electron donors. The prototype of these materials is polyacetylene (PA). There are various other conjugated polymers such as polyparaphenylene, polyphenylenevinylene, polypoyrrole or polythiophene. The doped systems, i.e. the conducting polymers, have intersting potential technological applications such as replacement of conventional metals in electronic shielding and antistatic equipment, rechargable batteries, and flexible light emitting diodes.Although these systems have been investigated almost 20 years, the electronic structure of the doped metallic systems is not clear and even the reason for the gap in undoped semiconducting systems is under discussion.

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