Ligand properties of the –OSeF5 and –OTeF5 groups in pseudo-trigonal-bipyramidal molecules
Abstract
The compounds F2Se(OSeF5)2, F2Se(OTeF5)2, and F2Te(OTeF5)2 have been prepared and their structures investigated by 77Se and 125Te n.m.r. spectroscopy. All three materials have pseudo-trigonal-bipyramidal structures with axial –OSeF5(–OTeF5) ligands, with the fluorine ligands in equatorial positions. This behaviour is discussed in terms of the extreme electronegativity of these ligands. F2Te(OTeF5)2 reacts further with FOTeF5 to give mer-F3Te(OTeF5)3 but no fac-F3Te(OTeF5)3. Selenium-77 n.m.r. spectroscopic data for numerous selenium fluorides are presented.