Reaction Mechanism of Silicon−Hydrogen Bond Activation Studied Using Femtosecond to Nanosecond IR Spectroscopy and Ab Initio Methods

1998 ◽  
Vol 120 (39) ◽  
pp. 10154-10165 ◽  
Author(s):  
H. Yang ◽  
M. C. Asplund ◽  
K. T. Kotz ◽  
M. J. Wilkens ◽  
H. Frei ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Reaction Mechanism ◽  
Ir Spectroscopy ◽  
Ab Initio ◽  
Bond Activation ◽  
Ab Initio Methods

Cooperative Effects in Aminothiols: Acid-Base Equilibria and the Molecular Structure of 2-(N, N-Dimethylaminomethyl)thiophenol

2008 ◽  
Vol 63 (10) ◽  
pp. 1199-1203
Author(s):  
Holger Fleischer ◽  
Dieter Schollmeyer
Keyword(s):  
Molecular Structure ◽  
Aqueous Solution ◽  
Hydrogen Bond ◽  
Solid State ◽  
Ab Initio ◽  
Ab Initio Methods ◽  
Asymmetric Unit ◽  
Acid Base ◽  
Cooperative Effects ◽  
Independent Molecules

Abstract2-(N,N-Dimethylaminomethyl)thiophenol, (1, HL), is present as a non-zwitterionic aminothiol in the solid state, exhibiting an intramolecular S-H···N hydrogen bond. The S···N distances of the two independent molecules in the asymmetric unit are 2.929(10) and 3.050(10) Å. This structural feature is also present in an ab initio (MP2/6-31G*) optimized molecular structure. The investigation of the hydrogen bond by ab initio methods supports an n(N)-σ *(S-H) interaction as the reason for this bond type. On the basis of data from potentiometric acid-base titrations of a 0.01 M aqueous solution of [H2L]Cl with a 0.1 M aqueous solution of sodium hydroxide, values of 4.09±0.01 and 11.50±0.01 were obtained for pKa1 and pKa2 of [H2L]+. pKa1 is much smaller than pKa of thiophenol while pKa2 is bigger than pKa of benzyldimethylamine. The increased difference between pKa1 and pKa2 is attributed to the stabilization of HL by the intramolecular S-H···N hydrogen bond.

Ab initio study of the structure of the hydrogen maleate anion

1993 ◽  
Vol 71 (3) ◽  
pp. 303-306 ◽  
Author(s):  
Miguel A. Ríos ◽  
Jesús Rodríguez
Keyword(s):  
Hydrogen Bond ◽  
Proton Transfer ◽  
Ab Initio ◽  
Electron Correlation ◽  
Basis Set ◽  
Ab Initio Methods ◽  
Ab Initio Study ◽  
Barrier Heights ◽  
Minimum Potential ◽  
Complete Optimization

The hydrogen maleate ion was studied by ab initio methods with complete optimization at the 3-21G, 6-31G, 6-31G**, and 6-31+G(2d,1p) levels. To study the influence of electron correlation, MP2 calculations have been done for the 6-31G** geometry. All calculations at the HF level predicted an asymmetric hydrogen bond with a double minimum potential governing transfer between the two equivalent structures. Moreover, both asymmetry and proton transfer barrier increase systematically with the power of the basis set used, with calculated barrier heights of 0.12 (3-21G), 1.59 (6-31G), 1.64 (6-31G**), and 2.00 kcal/mol (6-31+G). Only the introduction of the electron correlation at the MP2 level seems to predict a single minimum potential.

Ultrafast Infrared Studies of the Reaction Mechanism of Silicon−Hydrogen Bond Activation by η5-CpV(CO)4

1999 ◽  
Vol 103 (49) ◽  
pp. 10426-10432 ◽  
Author(s):  
Preston T. Snee ◽  
Haw Yang ◽  
Kenneth T. Kotz ◽  
Christine K. Payne ◽  
Charles B. Harris
Keyword(s):  
Hydrogen Bond ◽  
Reaction Mechanism ◽  
Bond Activation ◽  
Infrared Studies ◽  
Ultrafast Infrared

Determination of acidic dissociation constants of L-phenylalanyl-glycine and L-alanyl-L-alanine in water using ab initio methods

2014 ◽  
Vol 2 (42) ◽  
pp. 263-263
Author(s):  
Farhoush Kiani ◽  
Mahmoud Tajbakhsh ◽  
Fereydoon Ashrafi ◽  
Nesa Shafiei ◽  
Azar Bahadori ◽  
...  
Keyword(s):  
Ab Initio ◽  
Dissociation Constants ◽  
Ab Initio Methods ◽  
Acidic Dissociation

Nickel-Catalyzed Hydrosilylation of Terminal Alkenes with Primary Silanes via Electrophilic Silicon–Hydrogen Bond Activation

2021 ◽  
Vol 23 (4) ◽  
pp. 1434-1439
Author(s):  
Xiaoyu Wu ◽  
Guangni Ding ◽  
Wenkui Lu ◽  
Liqun Yang ◽  
Jingyang Wang ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Bond Activation ◽  
Terminal Alkenes

Study of the structure and stability of aqua ions La(H2O) n 3+ (n = 8, 9) by ab initio methods

2008 ◽  
Vol 53 (8) ◽  
pp. 1249-1255 ◽  
Author(s):  
V. Yu. Buz’ko ◽  
I. V. Sukhno ◽  
M. B. Buz’ko ◽  
A. A. Polushin ◽  
V. T. Panyushkin
Keyword(s):  
Ab Initio ◽  
Ab Initio Methods ◽  
Structure And Stability
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