Related Experiment Video
Updated: Jan 6, 2026

Construction and Systematical Symmetric Studies of a Series of Supramolecular Clusters with Binary or Ternary Ammonium Triphenylacetates
Published on: February 15, 2016
Conformational preference determined by inequivalent n-pairs: rotational studies on acetophenone and its monohydrate
Juncheng Lei1, Jiaqi Zhang, Gang Feng
1School of Chemistry and Chemical Engineering, Chongqing University, Daxuecheng South Rd. 55, 401331, Chongqing, China. qian.gou@cqu.edu.cn fengg@cqu.edu.cn.
Abstract:
Acetophenone and its complex with water have been investigated by using pulsed jet Fourier transform microwave spectroscopy complemented with quantum chemical calculations. Rotational spectra of the acetophenone monomer comprising nine isotopologues were measured and assigned, enabling the accurate structural description of the carbon skeleton. The most stable isomer of the monohydrate of acetophenone was detected in the supersonic jet expansion. Water serves as a proton donor and acceptor forming an O-HO[double bond, length as m-dash]C hydrogen bond and a secondary C-HO-H weak hydrogen bond with acetophenone through a six-membered ring. The water molecule lies almost in the plane of the aromatic ring. Bader's quantum theory of atoms in molecules, Johnson's non-covalent interaction, electron localization function and natural bond orbital analyses were applied to characterize the nature of the non-covalent interactions in the target complex. All rotational transitions are split into two components arising from the hindered methyl internal rotation. Upon the complexation, the V3 barrier to internal rotation of -CH3 slightly decreases, with 7.50(3) kJ mol-1 for the monomer, and 7.04(5) kJ mol-1 for the acetophenone-H2O dimer, respectively.
More Related Videos
Related Concept Videos
¹H NMR of Conformationally Flexible Molecules: Temporal Resolution
¹H NMR Chemical Shift Equivalence: Enantiotopic and Diastereotopic Protons
In chiral compounds such as 2-butanol, replacing the methylene hydrogens at C3 produces a pair of...
Chair Conformation of Cyclohexane
The hydrogen atoms linked to carbons are arranged in two different axial and equatorial orientations to achieve this...
Conformations of Ethane and Propane
Staggered conformation is a low energy and more stable conformation with the C-H bonds on the front carbon placed at 60°dihedral angles relative to the C-H bonds on the back carbon, leading to a reduced torsional strain. In staggered...
Structures of Carboxylic Acid Derivatives
Carboxylic acid derivatives contain an acyl group attached to a heteroatom such as chlorine, oxygen, or nitrogen. The carbonyl carbon and oxygen are both sp2-hybridized with an unhybridized p orbital.
The three sp2 orbitals of the carbonyl carbon form three σ bonds, one each with the carbonyl oxygen, the α carbon, and the heteroatom, whereas the other two sp2 orbitals of the carbonyl oxygen are occupied by the lone pairs. Further, the unhybridized p...
Prochirality

