Related Experiment Video
Updated: Apr 11, 2026

Probing the Structure and Dynamics of Interfacial Water with Scanning Tunneling Microscopy and Spectroscopy
Published on: May 27, 2018
Remarkable conformational flexibility of aqueous 18-crown-6 and its strontium(II) complex-ab initio molecular
Lorenz R Canaval1, Saprizal Hadisaputra, Thomas S Hofer
1Theoretical Chemistry Division, Institute of General, Inorganic and Theoretical Chemistry, University of Innsbruck, Innrain 80-82, A-6020 Innsbruck, Austria. T.Hofer@uibk.ac.at.
Abstract:
Ab initio QMCF-MD simulations of aqueous 18-crown-6 (18C6) and strontium(II)-18-crown-6 (18C6-Sr) were performed to gather insight into their hydration properties. Strongly different characteristics were found for the two solutes in terms of structure and dynamics such as H-bonding. They, however, have in common that their backbone shows high flexibility in aqueous medium, adopting structures significantly differing from idealized gas phase geometries. In particular, planar oxyethylene units stable in the picosecond range occurred in 18C6, while the strontium complex readily exhibits a bent structure. Detailed analysis of this high flexibility was done via two dimensional root mean square deviation plots as well as the evolution of dihedral angles and angles within the simulation trajectory. The vibrational spectra obtained from the QMCF-MD simulations are in excellent agreement with experimental data and show a pronounced blueshift upon complexation of the strontium(II) ion in 18C6.
More Related Videos
16:11Thermochemical Studies of NiII and ZnII Ternary Complexes Using Ion Mobility-Mass Spectrometry
Published on: June 8, 2022
08:54Vibrational Spectra of a N719-Chromophore/Titania Interface from Empirical-Potential Molecular-Dynamics Simulation, Solvated by a Room Temperature Ionic Liquid
Published on: January 25, 2020
Related Concept Videos
¹H NMR of Conformationally Flexible Molecules: Temporal Resolution
¹H NMR of Conformationally Flexible Molecules: Variable-Temperature NMR
Conformations of Cyclohexane
The chair form is the most stable and derives its name from its resemblance to the “easy chair.” In the chair conformation, two carbon atoms are arranged out-of-plane — one above and one below, minimizing the torsional strain. In the chair form, the bond angle is very close to the ideal...
Complexation Equilibria: Factors Influencing Stability of Complexes
Stability of Substituted Cyclohexanes
The two chair conformations of cyclohexanes undergo rapid interconversion at room temperature. Both forms have identical energies and stabilities, each comprising equal amounts of the equilibrium mixture. Replacing a hydrogen atom with a functional group makes the two conformations energetically non-equivalent.
For example, in...
Chair Conformation of Cyclohexane
The hydrogen atoms linked to carbons are arranged in two different axial and equatorial orientations to achieve this...