Microwave spectrum and intramolecular hydrogen bonding of 2-isocyanoethanol (HOCH(2)CH(2)N≡C).
The microwave spectrum of 2-isocyanoethanol (HOCH2CH2NC) has been investigated in the 12-120 GHz spectral range. The assignment of this spectrum was severely complicated by the rapid transformation of 2-isocyanoethanol into its isomer 2-oxazoline, which has a rich and strong spectrum. This process appeared both in a gold-plated microwave cell and in a brass cell and is presumed to be catalyzed by metals or traces of base. The spectrum of one conformer was ultimately assigned. This form is stabilized by an intramolecular hydrogen bond between the hydroxyl group and the isocyano group and is the first gas-phase study ever of this kind of hydrogen bonding. The distance between the hydrogen atom of the hydroxyl group and the nitrogen and carbon atoms are as long as 256 and 298 pm, respectively, indicating that covalent contribution to the hydrogen bond is minimal. Electrostatic forces are much more important because the O-H and N≡C bonds are almost parallel and the corresponding bond moments are practically antiparallel. The microwave work has been augmented by quantum chemical calculations at the CCSD(T)/cc-pVTZ and MP2/cc-pVTZ levels of theory. Results of these calculations are generally in good agreement with experimental findings.
Centre for Theoretical and Computational Chemistry (CTCC), Department of Chemistry, University of Oslo , Blindern, NO-0315 Oslo, Norway.
Harald
H
Møllendal
Svein
S
Samdal
Jean-Claude
JC
Guillemin
D000431:Ethanol / Q000031:analogs & derivatives* / Q000737:chemistry; D006860:Hydrogen Bonding; D008872:Microwaves; D009570:Nitriles / Q000737:chemistry*; D011789:Quantum Theory
C000593087:2-isocyanoethanol; D009570:Nitriles; D000431:Ethanol