Intramolecular Hydrogen-Bonding, Cation−π, and π-Stacking Interactions Affectingcis/trans Isomerization: Hexacarbonyltungsten Derivatives of Pyridyl-Substituted Arylphosphane Ligands

Abstract

A series of triphenylphosphane- and diphenyl(2-pyridyl)phosphane-substituted tetracarbonyltungsten derivatives has been prepared. Attractive intramolecular interactions between the phosphane ligands have been studied in both the neutral and protonated complexes; π-stacking, hydrogen-bonding, and cation−π bonding interactions were identified and were found to have an influence on the cis/trans isomerism of the complexes. It was found that the cis/trans isomerism could be switched by protonation or deprotonation of the diphenyl(2-pyridyl)phosphane derivatives. The complexes have been characterized by 31P-, 1H-, and 13C NMR spectroscopy, X-ray crystallography, IR spectroscopy, and mass spectrometry.