The rotational spectra of cyclobutanone-water (CY-W), dimethoxymethane-water (DMM-W) and dimethylether-water (DME-W) complexes have been recorded by molecular beam Fourier transform microwave spectroscopy and free jet millimeter-wave absorption spectroscopy. The study of several isotopomers of the molecules provided detailed information on the structure of the intramolecular hydrogen bond. In all cases the water molecule acts as a proton donor forming a bond with the sp2 (CY) or sp3 (DMM and DME) lone pair of the oxygen atom in the keton or ether molecule. A secondary CH•••O type interaction contribute to the stabilization of the DMM-W complex (see figure). Internal dynamic features characterize the spectra of DME-W and DMM-W complexes. In DME-W all rotational transitions are splitted as a consequence of the tunnelling motion of the water between the two equivalent oxygen lone pair. In DMM-W complex the splitting due to the internal rotation of the two methyl groups has been resolved.
Hydrogen bond structure arrangment and dynamical features of water adducts with ethers and ketones.
GIULIANO, BARBARA MICHELA;MELANDRI, SONIA;MARIS, ASSIMO;CAMINATI, WALTHER;VELINO, BIAGIO;
2005
Abstract
The rotational spectra of cyclobutanone-water (CY-W), dimethoxymethane-water (DMM-W) and dimethylether-water (DME-W) complexes have been recorded by molecular beam Fourier transform microwave spectroscopy and free jet millimeter-wave absorption spectroscopy. The study of several isotopomers of the molecules provided detailed information on the structure of the intramolecular hydrogen bond. In all cases the water molecule acts as a proton donor forming a bond with the sp2 (CY) or sp3 (DMM and DME) lone pair of the oxygen atom in the keton or ether molecule. A secondary CH•••O type interaction contribute to the stabilization of the DMM-W complex (see figure). Internal dynamic features characterize the spectra of DME-W and DMM-W complexes. In DME-W all rotational transitions are splitted as a consequence of the tunnelling motion of the water between the two equivalent oxygen lone pair. In DMM-W complex the splitting due to the internal rotation of the two methyl groups has been resolved.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
