Noncovalent interactions between isoflurane and dimethyl ether. Spectroscopic evidence of trimer formation

Abstract

The IR spectra of isoflurane + dimethyl ether mixtures dissolved in liquid Kr are registered at T ~118–160 K. The results obtained at a wide range of relative concentrations suggest the formation of complexes stabilized by non-covalent interactions of H-bond type. Large excess of DME and low temperature favor trimer formation stabilized by interactions between two DME moieties and both CH groups of isoflurane predominantly. Estimations based on ab initio calculation of spectroscopic and thermodynamic parameters confirm the experimental findings.