COMPUTATIONAL STUDY OF BRIDGE-MEDIATED INTERVALENCE ELECTRON TRANSFER II: COUPLINGS IN DIFFERENT METALLOCENE COMPLEXES

2012 ◽  
Vol 11 (06) ◽  
pp. 1341-1356 ◽  
Author(s):  
YINXI YU ◽  
HAOBIN WANG ◽  
SHAOWEI CHEN
Keyword(s):  
Electron Transfer ◽  
Density Functional ◽  
Computational Study ◽  
Mixed Valence ◽  
Functional Theory ◽  
Transfer Processes ◽  
Mediated Electron Transfer ◽  
Bridge Structures ◽  
Electron Transfer Processes ◽  
The Relationship

The constrained density functional theory (CDFT) was used to study bridge-mediated electron transfer processes in mixed-valence systems with two identical metallocene (cobaltocene, ruthenocene, and nickelocene) moieties linked by various bridge structures. Based on the electronic coupling matrix elements obtained from the CDFT calculations, the relationship between the bridge linkage and the effectiveness of intervalence transfer was discussed.

Highly Diastereoselective Functionalization of Piperidines by Photoredox Catalyzed C–H Arylation and Epimerization

2019 ◽  
Author(s):  
Morgan Walker ◽  
Brian Koronkiewicz ◽  
Shuming Chen ◽  
Kendall N Houk ◽  
James Mayer ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Transient Absorption ◽  
Transient Absorption Spectroscopy ◽  
Spectroscopic Methods ◽  
Reaction Conditions ◽  
Functional Theory ◽  
Transfer Processes ◽  
Electron Transfer Processes ◽  
Multiple Substitution

<div>We report a photoredox catalyzed α-amino C–H arylation reaction of highly substituted piperidine derivatives with electron deficient cyano(hetero)arenes. The scope and limitations of the reaction were explored, with piperidines bearing multiple substitution patterns providing the arylated products in good yields and with high diastereoselectivity. In order to probe the mechanism of the overall transformation, optical and fluorescent spectroscopic methods were used. By employing flash-quench transient absorption spectroscopy, we were able to observe electron transfer processes associated with radical formation beyond the initial excited state Ir(ppy)<sub>3</sub> oxidation. Following the rapid and unselective C–H arylation reaction, a slower epimerization occurs to provide the high diastereomer ratio observed for a large majority of the products. Several stereoisomerically pure products were re-subjected to the reaction conditions, each of which converged to the experimentally observed diastereomer ratios. The observed distribution of diastereomers corresponds to a thermodynamic ratio of isomers based upon their calculated relative energies using density functional theory (DFT).</div>

Switchable Electron-Transfer Processes in a Mixed-Valence, Kinetically Locked, Trinuclear RuII Metallamacrocycle

2004 ◽  
Vol 116 (30) ◽  
pp. 4028-4031 ◽  
Author(s):  
Naz Shan ◽  
Steven J. Vickers ◽  
Harry Adams ◽  
Michael D. Ward ◽  
Jim A. Thomas
Keyword(s):  
Electron Transfer ◽  
Mixed Valence ◽  
Transfer Processes ◽  
Electron Transfer Processes

scholarly journals An expression for the bridge-mediated electron transfer rate in dye-sensitized solar cells

2014 ◽  
Vol 372 (2013) ◽  
pp. 20130011 ◽  
Author(s):  
Emanuele Maggio ◽  
Alessandro Troisi
Keyword(s):  
Electron Transfer ◽  
Solar Cells ◽  
Density Functional ◽  
Dye Sensitized Solar Cells ◽  
Functional Theory ◽  
Dye Sensitized ◽  
Mediated Electron Transfer ◽  
Sensitized Solar Cells ◽  
Bridge Length ◽  
Structure Calculations

We have derived an expression for the rate of electron transfer between a semiconductor and a redox centre connected to the semiconductor via a molecular bridge. This model is particularly useful to study the charge recombination (CR) process in dye-sensitized solar cells, where the dye is often connected to the semiconductor by a conjugated bridge. This formalism, designed to be coupled with density functional theory electronic structure calculations, can be used to explore the effect of changing the bridge on the rate of interfacial electron transfer. As an example, we have evaluated the CR rate for a series of systems that differ in the bridge length.

Switchable Electron-Transfer Processes in a Mixed-Valence, Kinetically Locked, Trinuclear RuII Metallamacrocycle

2004 ◽  
Vol 43 (30) ◽  
pp. 3938-3941 ◽  
Author(s):  
Naz Shan ◽  
Steven J. Vickers ◽  
Harry Adams ◽  
Michael D. Ward ◽  
Jim A. Thomas
Keyword(s):  
Electron Transfer ◽  
Mixed Valence ◽  
Transfer Processes ◽  
Electron Transfer Processes

Effects of halogen substituted on the Mn-O electron transfer of NiMn2O4

2019 ◽  
Vol 33 (10) ◽  
pp. 1950090
Author(s):  
Hai-Long Li ◽  
Liang Bian ◽  
Fa-Qin Dong ◽  
Wei-Min Li ◽  
Hao Zou ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Oxygen Vacancy ◽  
Theoretical Basis ◽  
Density Functional ◽  
Mixed Valence ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Hybrid Orbital ◽  
Hybrid Orbitals ◽  
Valence Configuration

To observe the effect of halogen-substitution on the Mn-O electron transfer of NiMn2O4, we calculated Mn-mixed-valence configuration (charge-disproportionation) and oxygen vacancy by the density functional theory (DFT). The results indicate that the halogen-p5 state induces the O-2p orbital splitting to create an oxygen vacancy in the VB (valence band: about −5 eV). The oxygen vacancy can capture an electron from Mn[Formula: see text]-3d5 orbital that makes the Mn[Formula: see text]-3d5 change to Mn[Formula: see text]-3d4 states (Mn-charge disproportionate), and providing many effective-hole (40.14 [Formula: see text] 96.72 × 10[Formula: see text] kg). The halogen-p5-O-2p4 hybrid orbitals enhance the O-2p4-Mn-3d5 p-d hybrid orbital (about 19.18 electron). That increases the surface potential in Mn-O octahedron (for Cl-substituted: about 60 meV), the corresponding electron–electron interactions change from complex t[Formula: see text] (O-2p4-Mn[Formula: see text]-3d[Formula: see text] to complete [Formula: see text] (O-2p4-Mn[Formula: see text]-3d[Formula: see text]-e[Formula: see text](O-2p4-halogen-p5) orbital. This study effectively analyzes the microscopic changes of the electron transfer caused by the small amount of doping, provides a theoretical basis for the design of NMO-based semiconductor material.

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