Diglyme (C 6 H 14 O 3 ) complexes of molybdenum and tungsten: crystal structures of [MO 2 Cl 2 (C 6 H 14 O 3 )](M = Mo or W)

The diglyme complexes [MO2Cl2(C6H14O3)](M = Mo or W) have been prepared by reaction of MoO2Cl2 or WOCl4–Me3SiOSiMe3 with diglyme. X-Ray diffraction studies have shown that in these complexes the metals exhibit distorted-octahedral geometry, with cis-dioxo and trans-chloro ligands. Two ether oxygen atoms are co-ordinated trans to the oxo ligands leaving one terminal oxygen atom of the ligand uncomplexed. Assignments of metal–ligand stretching vibrations as observed by IR and Raman spectroscopy are presented. Variable temperature 13C-{1H} NMR spectra in CD2Cl2 solution indicate rapid intramolecular exchange between free and bound terminal oxygen atoms.