ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

A PCILO study of the hydrogen-bond of linear ethers and crown ethers with phenol

M. Omastová, J. Mlýnek, and A. Romanov

Polymer Institute, Centre for Chemical Research, Slovak Academy of Sciences, CS-842 36 Bratislava

Abstract: The PCILO method was used for calculation of interaction energies of phenol with linear and crown ethers. The geometry of all interacting molecules was at first completely optimized. The linear ethers represented systems of the structure R—(CH₂—CH₂—0)_x—R with the number of oxygen atoms x = 1,2, 3,4, 6 and R =—CH₃,—CH₂—CH₃. 1,4-Dioxan, 12-crown-4, and 18-crown-6 were calculated as cyclic ethers. Association energies were shown to be almost independent of the number of oxygen atoms in an ether molecule. This holds for both linear and cyclic ethers. Differences in association energies of linear and cyclic ethers are small (to 2kJmol^-1). As a whole, the hydrogen bond between associates may be considered as weak; it follows from the value of the energy (about — 20 k J mol^-1) and from the — О — О — distance, which is only little smaller than a sum of van der Waals radii of oxygen atoms.

Full paper in Portable Document Format: 422a205.pdf

Chemical Papers 42 (2) 205–212 (1988)