The preparation of bis(perfluoroethyl) tellurium difluoride and dichloride, trans perfluoroethyl tellurium monochloride tetrafluoride, trans bis(perfluoroethyl) tellurium tetrafluoride; and the preparation and X-ray crystal structure of perfluoroethyl tellurium trifluoride

• Published in: Canadian journal of chemistry 1985-08, Vol.63 (8), p.2273-2280
• Main Authors: Lau, Clement, Passmore, Jack, Richardson, E. Keith, Whidden, Tom K, White, Peter S
• Format: Article
• Language: English
• Subjects: Aliphatic compounds; Aliphatic, non-condensed and condensed benzenic, and alicyclic compounds; Chemistry; Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; Organic chemistry; Organic compounds; Physics; Preparations and properties; Structure of solids and liquids; crystallography; Structure of specific crystalline solids
• ISSN: 0008-4042; 1480-3291
• DOI: 10.1139/v85-374

The reaction of (C 2 F 5 ) 2 Te and XeF 2 in a slurry of SO 2 ClF yielded (C 2 F 5 ) 2 TeF 2 essentially quantitatively. Chlorine and (C 2 F 5 ) 2 Te gave (C 2 F 5 ) 2 TeCl 2 . Both (C 2 F 5 ) 2 TeF 2 and (C 2 F 5 ) 2 TeCl 2 were assigned a trigonal bipyramidal geometry, on the basis of their 19 F nmr and vibrational spectra, with the lone pair and C 2 F 5 groups in equatorial, and the halogens in the axial positions. Perfluoroethyl tellurium trifluoride was prepared essentially quantitatively by the reaction of C 2 F 5 TeTeC 2 F 5 and XeF 2 in liquid SO 2 F 2 . The generally inert SO 2 ClF was found to react with C 2 F 5 TeTeC 2 F 5 to give C 2 F 5 TeCl x F 3−x , and sulphur dioxide. The structure of C 2 F 5 TeF 3 was determined by X-ray diffraction. The crystals are tetragonal with a = 10.129(4), c = 25.561(6) Å, and Z = 16. The structure was refined in space group I4 1 /a to a conventional R factor of 0.051 for 901 observed reflections with I ≥ 3σ(I). Each tellurium atom is surrounded by two terminal fluorine atoms and two bridging fluorine atoms and a C 2 F 5 group in an axial position around the apex of a distorted square pyramid. The square-pyramidal units are linked by symmetrical cis bridging atoms into endless chains with bridging angles of 180° and 177°. The geometry of the (C 2 F 5 TeF 4 ) group is consistent with steric activity of the non-bonded electron pair. The 19 F nmr and Raman spectra of C 2 F 5 TeF 3 were recorded and the Raman spectrum assigned. Trans-C 2 F 5 TeClF 4 was prepared by the reaction of C 2 F 5 TeTeC 2 F 5 , and an excess of ClF. The trans octahedral geometry of C 2 F 5 TeClF 4 was unambiguously assigned from its 19 F nmr and vibrational spectra. A mixture of trans-(C 2 F 5 ) 2 TeF 4 and trans-C 2 F 5 TeClF 4 was obtained from the reaction of (C 2 F 5 ) 2 Te and an excess of ClF. Trans geometry of (C 2 F 5 ) 2 TeF 4 was unambiguously assigned from its 19 F nmr spectrum.