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Hydrogen bonding in pure base media. Correlations between calorimetric and infrared spectroscopic data
Author(s) -
Stolov Andrey A.,
Borisover Mikhail D.,
Solomonov Boris N.
Publication year - 1996
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/(sici)1099-1395(199605)9:5<241::aid-poc782>3.0.co;2-c
Subject(s) - chemistry , hydrogen bond , single bond , nitromethane , infrared spectroscopy , enthalpy , crystallography , molecule , organic chemistry , thermodynamics , alkyl , physics
The known correlations between calorimetric and IR spectroscopic data on hydrogen bonding were reinvestigated for hydrogen bond donors (AH) dissolved in pure bases (B). Ninety‐five AH···B systems were considered for which the enthalpies of specific interaction due to hydrogen bonding AH···B (Δ H AH/B sp.int. , kJ mol −1 ), the weight centers of A‐H stretching bands ( v , cm −1 ) and their integral absorption coefficients (α, 10 4 cm mmol −1 ) had been measured. The relationships between Δ H AH/B sp.int. and the parameters of the infrared absorption spectra [weight center shifts Δ v and the changes in the square roots of α (Δα 1/2 )] were analyzed. It was found that the dependence of Δ H AH/B sp.int. on Δα 1/2 consists of two nearly parallel straight lines: the first (−Δ H AH/B sp.int. = 12·0 Δα 1/2 + 0·4) corresponds to water and the weak C(SINGLE BOND)H and O(SINGLE BOND)H H‐bond donors (chloroethylenes, acetylenes acetonitrile, nitromethane, chloroform, o , o′‐di‐ tert ‐butylphenol); the second (−Δ H AH/B sp.int. = 12·1 Δα 1/2 −4·2) corresponds to the stronger N(SINGLE BOND)H and O(SINGLE BOND)H H‐bond donors ( N ‐methylaniline, pyrrole, alcohols, phenol, carbon acids). Non‐linear dependences of Δ H AH/B sp.int. on Δ v were obtained for all C(SINGLE BOND)H, N(SINGLE BOND)H and O(SINGLE BOND)H H‐bond donors except water [−Δ H AH/B sp.int. = 59·9 Δ v /(Δ v + 674)]. Enthalpies of specific interaction for water obey another dependence [−Δ H H 2 O/Bsp.int. /2 = 28·5 Δ v /(Δ v + 269)]. The Δ H AH/B sp.int. values can be estimated by the above correlations with an accuracy of ±3 to ±6 kJ mol −1 . These relationships obtained for solutions of H‐bond donors in pure bases differ from the well known dependences determined for the AH···B hydrogen bonding in carbon tetrachloride medium.