P. Huppmann

Ligand properties of the -OSeF5 and -OTeF5 groups in pseudo-trigonal-bipyramidal molecules

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.

Transition metal derivatives with the OTeF5 group

Abstract −OTeF5 Derivatives are presented of Ti, V, Nb, Ta, Cr, Mo, W, Re, Os and Au. The coordination behaviour of these central atoms are discussed. Ti, V, and Cr prefer tetrahedral environment, Mo, Os, and Re prefer a pentacoordinated species, while W (as the long-known U-derivatives) prefers the octahedral environment. Some crystal structures are presented.

Selenium-nitrogen and tellurium-nitrogen compounds

Abstract Te-N and Se-N compounds are notoriously unstable. However, starting with H 2 NTeF 5 or (CH 3 ) 3 SiNHTeF 5 a variety of tellurium nitrogen compounds have been prepared, such as F 5 TeNSF 2 , F 5 TeNPF 3 , F 5 TeNCl 2 a.o. A crystal structure is given of F 5 TeNWCl 4 , and an electron diffraction structure of F 5 TeNCO. Whereas F 5 SNCO has a similar structure, F 5 SeOCN appears as cyanate! The first selenium-nitrogen double bond systems have been prepared with F 5 TeNSeCl 2 and F 5 TeNSeF 2 .