Ionic hydrogen bond and ion solvation. 7. Interaction energies of carbanions with solvent molecules

Journal Article · Wed Jun 08 00:00:00 EDT 1988 · J. Am. Chem. Soc.; (United States)

DOI:https://doi.org/10.1021/ja00220a022· OSTI ID:7003544

Meot-Ner Mautner, M

The bonding energy of a water molecule to carbanions ranges from 11.0 kcal/mol for c-C/sub 5/H/sub 5//sup -/ to 13-15 kcal/mol for CH/sub 2/CH/sup -/, CH/sub 2/CHO/sup -/, and CH/sub 2/COCH/sub 3//sup -/ and to 16.2 kcal/mol for HCC/sup -/. Alcohols bond to c-C/sub 5/H/sub 5//sup -/ more strongly, by up to 20.6 kcal/mol for the strongly acidic CF/sub 3/CH/sub 2/OH, and the attachment energies show an inverse linear correlation with the acidities of the alcohols. The c-C/sub 5/H/sub 5//sup -/ ion exhibits unusual behavior in that it bonds to the hydrogen donor H/sub 2/O more weakly (11.0 kcal/mol) than to CH/sub 3/CN (15.5 kcal/mol). In contrast, the more localized pyrrolide ion c-C/sub 4/H/sub 4/N/sup -/ bonds to the two solvents by comparable strength, 15.8 and 15.7 kcal/mol, respectively. These observations indicate a specific N/sup -/ x OH hydrogen bonding contribution in c-C/sub 4/H/sub 4/N/sup -/ x H/sub 2/O, and/or an unusual C/sup -/ x HC type hydrogen-bonding contribution in c-C/sub 5//sup -/ x CH/sub 3/CN. As to structures, correlations between ..delta..H/sup 0//sub D/ and ..delta..H/sup 0//sub acid/ suggest that ligands may hydrogen bond to the ..pi.. system of c-C/sub 5/H/sub 5//sup -/, and to the oxygen atoms in CH/sub 2/CHO/sup -/ and CH/sub 3/COCH/sub 2//sup -/. The latter is also supported by solvent shell effects in CH/sub 3/COCH/sub 2//sup -/ x nH/sub 2/O.

• Research Organization: National Bureau of Standards, Gaithersburg, MD (USA)
• OSTI ID: 7003544
• Journal Information: J. Am. Chem. Soc.; (United States), Journal Name: J. Am. Chem. Soc.; (United States) Vol. 110:12; ISSN JACSA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ALCOHOLS
ANIONS
CARBANIONS
CHARGED PARTICLES
CHEMICAL BONDS
DATA
ELEMENTS
EXPERIMENTAL DATA
HYDROGEN
HYDROGEN COMPOUNDS
HYDROXY COMPOUNDS
INFORMATION
IONS
MOLECULES
NONMETALS
NUMERICAL DATA
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
SOLVATION
SOLVENT PROPERTIES
THERMODYNAMIC PROPERTIES
WATER