Chloromethyl phenyl ether in the gas phase, studied by electron diffraction, infrared spectroscopy and ab initio calculations

Abstract

The molecular structure of chloromethyl phenyl ether (CMPE) is investigated from gas phase electron diffraction data and IR frequencies in CS 2 solution, complemented with geometry relaxed ab initio calculations on the HF/4-21G/3-3-31G level. The anomeric effect greatly affects the geometrical parameters, among other things making the C(sp 3)O bond shorter than the C(sp 2)O bond. Furthermore, the anomeric interaction significantly shifts the equilibrium between an e rotameric form (OC(sp 3) in-plane with phenyl ring) and an o rotameric (OC(sp 3) approximately perpendicular to phenyl ring) towards the o form. In fact CMPE appears as a mixture of about equal amounts of ( e, sc) and ( o, sc) conformations. The IR spectral frequencies are reassigned and analogous geometrical trends with anisole rotamers are discussed.