On the influence of the ratio between the proton donor and acceptor concentrations on the relative error in the determination of the equilibrium constant of complexes formation with a hydrogen bond in the case of proton donor self-association

Author(s):  
E. Valiev ◽  
M. Sheyh-Zade
1980 ◽  
Vol 58 (13) ◽  
pp. 1372-1375 ◽  
Author(s):  
J. N. Spencer ◽  
Robert C. Garrett ◽  
Fred J. Mayer ◽  
Johanna E. Merkle ◽  
Carla R. Powell ◽  
...  

Thermodynamic parameters for the self-association of N-methylformamide and N-methylacetamide in CCl4 solvent have been determined by infrared spectroscopy. The pure base calorimetric method was used to determine the enthalpy of hydrogen bond complex formation of N-methylformamide and N-methylacetamide with N,N-dimethylformamide, N,N-dimethylacetamide, ethyl acetate, and dioxane. Comparison of the calorimetric and spectroscopic results show that the dimers of N-methylformamide and N-methylacetamide are linear with hydrogen bond enthalpies of −2.9 and −3.9 kcal mol−1 respectively. The carbonyl group of N-methylacetamide was found to be a better proton accepter than the carbonyl of N-methylformamide in agreement with theoretical predictions. N-methylacetamide was found to be a better proton donor than N-methylformamide in disagreement with theoretical predictions. The dimer self-association constants appear to be larger than previously reported.


Molecules ◽  
2020 ◽  
Vol 25 (21) ◽  
pp. 4899
Author(s):  
Juncheng Lei ◽  
Silvia Alessandrini ◽  
Junhua Chen ◽  
Yang Zheng ◽  
Lorenzo Spada ◽  
...  

The most stable isomer of the 1:1 complex formed by 2,2,2-trifluoroacetophenone and water has been characterized by combining rotational spectroscopy in supersonic expansion and state-of-the-art quantum-chemical computations. In the observed isomer, water plays the double role of proton donor and acceptor, thus forming a seven-membered ring with 2,2,2-trifluoroacetophenone. Accurate intermolecular parameters featuring one classical O-H···O hydrogen bond and one weak C-H···O hydrogen bond have been determined by means of a semi-experimental approach for equilibrium structure. Furthermore, insights on the nature of the established non-covalent interactions have been unveiled by means of different bond analyses. The comparison with the analogous complex formed by acetophenone with water points out the remarkable role played by fluorine atoms in tuning non-covalent interactions.


1983 ◽  
Vol 27 ◽  
Author(s):  
L. Salamanca-Riba ◽  
B.S. Elman ◽  
M.S. Dresselhaus ◽  
T. Venkatesan

ABSTRACTRutherford backscattering spectrometry (RBS) is used to characterize the stoichiometry of graphite intercalation compounds (GIC). Specific application is made to several stages of different donor and acceptor compounds and to commensurate and incommensurate intercalants. A deviation from the theoretical stoichiometry is measured for most of the compounds using this non-destructive method. Within experimental error, the RBS results agree with those obtained from analysis of the (00ℓ) x-ray diffractograms and weight uptake measurements on the same samples.


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