scholarly journals A Mechanistic Investigation into the Zinc Carbenoid-Mediated Homologation Reaction by DFT Methods: Is a Classical Donor−Acceptor Cyclopropane Intermediate Involved?

2010 ◽  
Vol 75 (21) ◽  
pp. 7322-7331 ◽  
Author(s):  
Wilhelm A. Eger ◽  
Charles K. Zercher ◽  
Craig M. Williams
Keyword(s):  
Dft Methods ◽  
Mechanistic Investigation ◽  
Donor Acceptor ◽  
Zinc Carbenoid

Assessing the performance of commonly used DFT functionals in studying the chemistry of frustrated Lewis pairs

2014 ◽  
Vol 13 (01) ◽  
pp. 1350074 ◽  
Author(s):  
Fang Huang ◽  
Jinliang Jiang ◽  
Mingwei Wen ◽  
Zhi-Xiang Wang
Keyword(s):  
Lewis Acids ◽  
Density Functional ◽  
Basis Set ◽  
Basis Sets ◽  
Frustrated Lewis Pairs ◽  
Dft Methods ◽  
Functional Theory ◽  
Donor Acceptor ◽  
Reaction Barriers ◽  
Better Than

The benchmark study has assessed the performance of 18 density functional theory (DFT) functionals, including GGAs, hybrid-GGAs, meta-GGAs, and hybrid meta-GGAs, in predicting bonding strength, barrier height and structure for systems involving Lewis acids and bases. Three databases were built for the study, including 15 bonding enthalpies of dative bonds (DBH15), 10 reaction barriers (BH10) and 10 X-ray structures (XCS10). Wavefunction-based ab initio calculations were also carried out for comparisons. The benchmark data were computed at the CCSD(T)/BSI//MP2/BSI(BSI=aug-cc-pVTZ) level. The 6-311++G(d,p)(BSII) and 6-31G(d,p)(BSIII) basis sets were employed in DFT calculations. Generally, M06-2X/BSII and M05-2X/BSII outperform the other tested DFT methods. M05-2X/BSIII and M06-2X/BSIII are less accurate than M05-2X/BSII and M06-2X/BSII (or M05-2X/BSII//M05-2X/BSIII and M06-2X/BSII//M06-2X/BSIII), suggesting that large basis sets (e.g. BSII) are necessary to improve energetics. SCS-MP2 is less accurate than MP2, consistently overestimating bonding enthalpies and reaction barriers. Moreover, six DFT functionals (M05-2X, M06-2X, B3LYP, ωB97X-D, BMK and B97-D) were examined by comparing with the experimental bonding enthalpies of eighteen donor–acceptor complexes, which indicate that M05-2X and M06-2X are still better than others. Nevertheless, M05-2X and M06-2X significantly overestimate or underestimate the bonding enthalpies of F-substituted complexes, implying the necessity of improving the two functionals for describing fluorides. Using the six basis sets (BSI, cc-pVTZ, aug-cc-pVDZ, cc-pVDZ, TZVP and BSII) and DBH15 and BH10 databases, the influence of the basis sets on the performance of M06-2X functional was examined, which reveals that BSII is the most suitable basis set for the functional.

Analysis of time-resolved donor-acceptor-pair spectra of ZnSe : Li and ZnSe : N

1998 ◽  
Vol 184-185 (1-2) ◽  
pp. 531-535
Author(s):  
P Bäume
Keyword(s):  
Acceptor Pair ◽  
Time Resolved ◽  
Donor Acceptor ◽  
Donor Acceptor Pair

Approaches to empirical donor-acceptor and polarity-parameters of polymers in solution and at interfaces

1992 ◽  
Vol 89 ◽  
pp. 1615-1622 ◽  
Author(s):  
S Spange ◽  
D Keutel ◽  
F Simon
Keyword(s):  
Donor Acceptor ◽  
Polarity Parameters

Evidence of a donor-acceptor type transition in CuGaSe2

1980 ◽  
Vol 41 (7) ◽  
pp. 707-712 ◽  
Author(s):  
A. Poure ◽  
G. Aguero ◽  
G. Masse ◽  
J.P. Aicardi
Keyword(s):  
Type Transition ◽  
Donor Acceptor

NET PHOTOSYNTHESIS AND EAR GRAIN CONTENT IN THE VARIETIES OF SPRING WHEAT UNDER THE INFLUENCE OF DONOR-ACCEPTOR RELATIONS

2012 ◽  
pp. 66-71
Author(s):  
E.F. Ionov ◽  
◽  
N.E. Ionova ◽  
V.A. Dragavtsev ◽  
◽  
...  
Keyword(s):  
Spring Wheat ◽  
Net Photosynthesis ◽  
Donor Acceptor

Photoactive donor-acceptor thin films as prospective materials for evaporated bulk heterojunctions of molecular semiconductors

2008 ◽  
Author(s):  
Derck Schlettwein ◽  
Robin Knecht ◽  
Dominik Klaus ◽  
Christopher Keil ◽  
Günter Schnurpfeil
Keyword(s):  
Thin Films ◽  
Bulk Heterojunctions ◽  
Donor Acceptor ◽  
Molecular Semiconductors

A New Deep Acceptor in Epitaxial Cubic SiC

1989 ◽  
Vol 162 ◽  
Author(s):  
J. A. Freitas ◽  
S. G. Bishop
Keyword(s):  
Thin Films ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Excitation Intensity ◽  
Acceptor Pair ◽  
Deep Acceptor ◽  
Intensity Dependence ◽  
Pl Spectra ◽  
Donor Acceptor ◽  
Donor Acceptor Pair

ABSTRACTThe temperature and excitation intensity dependence of photoluminescence (PL) spectra have been studied in thin films of SiC grown by chemical vapor deposition on Si (100) substrates. The low power PL spectra from all samples exhibited a donor-acceptor pair PL band which involves a previously undetected deep acceptor whose binding energy is approximately 470 meV. This deep acceptor is found in every sample studied independent of growth reactor, suggesting the possibility that this background acceptor is at least partially responsible for the high compensation observed in Hall effect studies of undoped films of cubic SiC.

Quantum Dot Bioconjugates as Energy Donors in Fluorescence Resonance Energy Transfer Assays

2003 ◽  
Vol 773 ◽  
Author(s):  
Aaron R. Clapp ◽  
Igor L. Medintz ◽  
J. Matthew Mauro ◽  
Hedi Mattoussi
Keyword(s):  
Energy Transfer ◽  
Quantum Dot ◽  
Organic Dyes ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Genetically Engineered ◽  
Molar Ratio ◽  
Binding Assays ◽  
Specific Sequence ◽  
Donor Acceptor

AbstractLuminescent CdSe-ZnS core-shell quantum dot (QD) bioconjugates were used as energy donors in fluorescent resonance energy transfer (FRET) binding assays. The QDs were coated with saturating amounts of genetically engineered maltose binding protein (MBP) using a noncovalent immobilization process, and Cy3 organic dyes covalently attached at a specific sequence to MBP were used as energy acceptor molecules. Energy transfer efficiency was measured as a function of the MBP-Cy3/QD molar ratio for two different donor fluorescence emissions (different QD core sizes). Apparent donor-acceptor distances were determined from these FRET studies, and the measured distances are consistent with QD-protein conjugate dimensions previously determined from structural studies.

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