Validity of the Derjaguin Approximation on Electrostatic Effect in the Frumkin−Derjaguin Approach

Langmuir ◽  
2003 ◽  
Vol 19 (23) ◽  
pp. 9962-9967 ◽  
Author(s):  
Kwan Hyoung Kang ◽  
In Seok Kang

2001 ◽  
Vol 56 (12) ◽  
pp. 1360-1368 ◽  
Author(s):  
Robert Weiss ◽  
Frank Pühlhofer

Abstract 4-Fluorobenzenesulfonyl chloride (1) and pentafluorobenzenesulfonyl chloride (2) are transformed into the corresponding N-sulfonylpyridinium triflates 4a-d by treatment with one equivalent of the reagent pair L/TMSOTf (L = 4-dimethylaminopyridine (DMAP), 4-ferf-butylpyridine (TBUPY), 1-methylimidazole (NMI); TMSOTf = trimethylsilyl triflate). Due to the electrostatic effect of the sulfonylonio function, SNAr reactions on these systems can be performed under mild conditions. So the reaction of 2 with excess DMAP/TMSOTf leads by way of peronio substitution to hexakis[(4-dimethylamino)-l-pyridinio]benzene hexa-kis(trifluoromethansulfonate) (7) [22] at room temperature. Additionally, a new reaction path to 4-(1-pyridinio)-substituted benzenesulfonamides, a class of pharmaceutically interesting substances, is shown.





AIChE Journal ◽  
1996 ◽  
Vol 42 (6) ◽  
pp. 1590-1599 ◽  
Author(s):  
Yu-Feng Zhang ◽  
Yi Yang ◽  
Hamid Arastoopour


1989 ◽  
Vol 5 (04) ◽  
pp. 385-387
Author(s):  
Lai Luhua ◽  
◽  
Luo Yu ◽  
Xu Xiaojie ◽  
Shao Meicheg ◽  
...  


2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Jin Kyun Kim ◽  
Cheol Lee ◽  
Seon Woo Lim ◽  
Aniruddha Adhikari ◽  
Jacob T. Andring ◽  
...  

Abstract Why metalloenzymes often show dramatic changes in their catalytic activity when subjected to chemically similar but non-native metal substitutions is a long-standing puzzle. Here, we report on the catalytic roles of metal ions in a model metalloenzyme system, human carbonic anhydrase II (CA II). Through a comparative study on the intermediate states of the zinc-bound native CA II and non-native metal-substituted CA IIs, we demonstrate that the characteristic metal ion coordination geometries (tetrahedral for Zn2+, tetrahedral to octahedral conversion for Co2+, octahedral for Ni2+, and trigonal bipyramidal for Cu2+) directly modulate the catalytic efficacy. In addition, we reveal that the metal ions have a long-range (~10 Å) electrostatic effect on restructuring water network in the active site. Our study provides evidence that the metal ions in metalloenzymes have a crucial impact on the catalytic mechanism beyond their primary chemical properties.





2007 ◽  
Vol 111 (14) ◽  
pp. 3831-3838 ◽  
Author(s):  
Tomohiro Kimura ◽  
Keiko Ninomiya ◽  
Shiroh Futaki
Keyword(s):  


2006 ◽  
Vol 8 (21) ◽  
pp. 2531 ◽  
Author(s):  
Samuel Rentsch ◽  
Ramon Pericet-Camara ◽  
Georg Papastavrou ◽  
Michal Borkovec


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