Role of Heavy Atom Tunneling in Myers–Saito Cyclization of Cyclic Enyne-Cumulene Systems

2016 ◽  
Vol 120 (5) ◽  
pp. 945-950 ◽  
Author(s):  
Sharmistha Karmakar ◽  
Ayan Datta
Keyword(s):  
Heavy Atom

BODIPY‐Based Photosensitizers as Potential Anticancer and Antibacterial Agents: Role of the Positive Charge and the Heavy Atom Effect

ChemMedChem ◽  
2020 ◽  
Author(s):  
Jaroslaw Piskorz ◽  
Weronika Porolnik ◽  
Malgorzata Kucinska ◽  
Jolanta Dlugaszewska ◽  
Marek Murias ◽  
...  
Keyword(s):  
Antibacterial Agents ◽  
Positive Charge ◽  
Heavy Atom ◽  
Heavy Atom Effect ◽  
Atom Effect

Where is the Heavy-Atom Effect? Role of the Central Ligand in Tetragold(I) Ethynyl Complexes

2010 ◽  
Vol 122 (48) ◽  
pp. 9392-9395 ◽  
Author(s):  
Glenna So Ming Tong ◽  
Pui Keong Chow ◽  
Chi-Ming Che
Keyword(s):  
Heavy Atom ◽  
Heavy Atom Effect ◽  
Atom Effect

Magnetic Anisotropy in Co II X 4 (X=O, S, Se) Single‐Ion Magnets: Role of Structural Distortions versus Heavy Atom Effect

2019 ◽  
Vol 14 (24) ◽  
pp. 4696-4704 ◽  
Author(s):  
Arup Sarkar ◽  
Subrata Tewary ◽  
Shwetali Sinkar ◽  
Gopalan Rajaraman
Keyword(s):  
Magnetic Anisotropy ◽  
Heavy Atom ◽  
Heavy Atom Effect ◽  
Structural Distortions ◽  
Atom Effect

Effect of radiation damage on the molecular image of Th-Phthalocyanine

1978 ◽  
Vol 36 (1) ◽  
pp. 300-301 ◽  
Author(s):  
Takashi Kobayashi ◽  
Natsu Uyeda
Keyword(s):  
Organic Molecules ◽  
Heavy Atom ◽  
High Vacuum ◽  
High Sensitivity ◽  
High Resolution Electron Microscopy ◽  
Molecular Image ◽  
Resolution Electron ◽  
Damage Process ◽  
Intense Electron

Because of a high sensitivity of organic molecules to the electron irradiation, it is difficult to analyse the structure of organic materials with a high resolution electron microscopy in atomic resolution.It is expected to be possible as the second best to detect a position of a heavy atom in a molecule even when the molecule became a skeleton as a result of intense electron bombardment. This paper is to report on the effect of damage on molecular image and a role of a heavy atom in the damage process.The specimen is a thin crystalline film of tholium-phthalocyanine (Th-Pc) prepared by epitaxial growth. The film deposited on a single crystal (001)face of KCl by high vacuum evaporation and the thickness was monitored by the use of quartz crystal microbalance to be about 100 A and 50A. The film was supported on gold coated microgrid with small holes of 1-2μm in diameter.

scholarly journals Linking protein structure and dynamics to catalysis: the role of hydrogen tunnelling

2006 ◽  
Vol 361 (1472) ◽  
pp. 1323-1331 ◽  
Author(s):  
Judith P Klinman
Keyword(s):  
Critical Role ◽  
Heavy Atom ◽  
Hydrogen Atom Transfer ◽  
Transfer Reactions ◽  
Structure And Dynamics ◽  
Alternate Model ◽  
Reaction Barriers ◽  
Hydrogen Isotope Effect ◽  
The Impact

Early studies of enzyme-catalysed hydride transfer reactions indicated kinetic anomalies that were initially interpreted in the context of a ‘tunnelling correction’. An alternate model for tunnelling emerged following studies of the hydrogen atom transfer catalysed by the enzyme soybean lipoxygenase. This invokes full tunnelling of all isotopes of hydrogen, with reaction barriers reflecting the heavy atom, environmental reorganization terms. Using the latter approach, we offer an integration of the aggregate data implicating hydrogen tunnelling in enzymes (i.e. deviations from Swain–Schaad relationships and the semi-classical temperature dependence of the hydrogen isotope effect). The impact of site-specific mutations of enzymes plays a critical role in our understanding of the factors that control tunnelling in enzyme reactions.

Where is the Heavy-Atom Effect? Role of the Central Ligand in Tetragold(I) Ethynyl Complexes

2010 ◽  
Vol 49 (48) ◽  
pp. 9206-9209 ◽  
Author(s):  
Glenna So Ming Tong ◽  
Pui Keong Chow ◽  
Chi-Ming Che
Keyword(s):  
Heavy Atom ◽  
Heavy Atom Effect ◽  
Atom Effect

The Role of Conjugative Interaction in Stable Carbenes of the 1,2,4-Triazol-5-ylidene Type and their Energy of Dimerization. An Ab Initio Study

1996 ◽  
Vol 51 (1-2) ◽  
pp. 95-101 ◽  
Author(s):  
Gerhard Raabe ◽  
Klaus Breuer ◽  
Dieter Enders ◽  
J. Henrique Teles
Keyword(s):  
Ab Initio ◽  
Heavy Atom ◽  
Stationary Points ◽  
Stable Isomer ◽  
Ab Initio Study ◽  
Model Compounds ◽  
Ab Initio Theory ◽  
Singlet Carbenes ◽  
Different Levels

Abstract The role of conjugative interaction in stable carbenes of the 1,2,4-triazol-5-ylidene type was studied at different levels of ab initio theory employing model compounds. In the case of parent 4,5-dihydro-1 H-1,2,4-triazol-5-ylidene this type of interaction was found to be of similar importance as in 1,2,4-triazole and pyridine.Five stationary points were located on the hypersurface of the dimer (C2N3H3)2 . ΔE for all considered dimerization reactions was found to be negative, and the change of energy associated with the formation of the most stable isomer is about -9.5 kcal/mol. In spite of a high value for the singlet-triplet gap of about 90 kcal/mol for the carbene, the heavy atom skeleton of the most stable dimer is close to planarity. This finding is in perfect accordance with the predictions of other authors regarding the geometry of dimers from singlet carbenes stabilized by π-conjugation.

Sign in / Sign up

Export Citation Format

Share Document