Jarkko Pietikäinen

Halogenation of tellurium by SO2Cl2. Formation and crystal structures of (H3O)[Te3Cl13]·1/2SO2, [(C4H8O)2H][TeCl5]·(C4H8O), [(Me2SO)2H]2[TeCl6], and [Ni(NCCH3)6][Te2Cl10]

Abstract The halogenation of elemental tellurium with SO2Cl2 in various solvents has been investigated. (H3O)[Te3Cl13]·1/2SO2 (1) and [(C4H8O)2H][TeCl5]·(C4H8O) (2) were obtained in CS2 and THF, respectively. When DMSO is added into the THF solution of tellurium and SO2Cl2, [(Me2SO)2H]2[TeCl6] (3) is formed. In the acetonitrile solution tellurium and SO2Cl2 form [Ni(NCCH3)6][Te2Cl10] (4) in the presence of metallic nickel. All compounds 1–4 were characterized by 125Te NMR and by X-ray crystallography. The formation of the anions has been discussed.

Cation-anion interactions in triphenyl telluronium salts. The crystal structures of (Ph3Te)2[MCl6] (M = Pt, Ir), (Ph3Te)[AuCl4], and (Ph3Te)(NO3).HNO3

Abstract Triphenyltelluronium hexachloroplatinate ( 1 ), hexachloroiridate ( 2 ), tetrachloroaurate ( 3 ), and tetrachloroplatinate ( 4 ) were prepared from Ph 3 TeCl and potassium salts of the corresponding anions. Upon recrystallization of 4 from concentrated nitric acid, K 2 [PtCl 6 ] and (Ph 3 Te)(NO 3 )·HNO 3 ( 5 ) were obtained. The crystal structures of 1 – 3 and 5 are reported. Compounds 1 and 2 are isostructural. They are triclinic, P 1, Z =2 (the asymmetric unit contains two formula units). Compound 1 : a =10.7535(2), b =17.2060(1), c =21.4700(3) A, α =78.9731(7), β =77.8650(4), γ =78.8369(4)°. Compound 2 : a =10.7484(2), b =17.1955(2), c =21.4744(2) A, α =78.834(1), β =77.649(1), γ =78.781(1)°. Compound 3 is monoclinic, P 2 1 / c , Z =4, a =8.432(2), b =14.037(3), c =17.306(3) A, β =93.70(3)°. Compound 5 is monoclinic. P 2 1 / n , Z =4, a =9.572(2), b =14.050(3), c =13.556(3) A, β =90.76(3)°. The primary bonding in the Ph 3 Te + cation in each salt is a trigonal AX 3 E pyramid with TeC bond lengths in the range 2.095(8)–2.14(2) A and the bond angles 94.1(6)–100.9(5)°. The weak Te⋯Cl ( 1 – 3 ) and Te⋯O ( 5 ) secondary interactions expand the coordination sphere. In 1 and 2 the cation shows a trigonal bipyramidal AX 3 YE coordination with one primary TeC bond and the shortest secondary Te⋯Cl contact in axial positions and the two other TeC bonds and the lone-pair in equatorial positions. The cation in 3 shows a distorted octahedral AX 3 Y 3 E environment and that in 5 is a more complex AX 3 Y 3 Y′ 2 arrangement. In both latter salts the structure is a complicated three-dimensional network of cations and anions.

Formation and crystal structure of polymeric (MeTeCl3)n

Abstract The reaction of hexamethyldisilane with tellurium tetrachloride in carbon disulfide afforded polymeric (MeTeCl3)n (1) that was characterized by TOF ES mass spectroscopy, 125Te NMR spectroscopy, and X-ray crystallography. Pale brown, air-and moisture-sensitive crystals of 1 are monoclinic, space group P21/n with a = 1030.69(5), b = 643.61(2), c = 1041.68(5) pm, ß = 119.236(5)°, V = 0.60299(5) nm3, and Z = 4. The crystal structure consists of infinite helical chains of the MeTeCl3 units linked by bridging chlorine atoms. The polymeric chains are linked together by Te···Cl and Cl···Cl close contacts. The possible routes for the formation of (MeTeCl3)n are discussed.

Reversible Dissociation of (Se6I2)(AsF6)2 in SO2(I)

The dissociation of (Se6I2)(AsF6)2 in SO2(1) has been investigated by 77Se NMR spectroscopy at –80 °C involving both a natural-abundance sample as well as that containing selenium enriched in the 77Se-isotope (enrichment 92 %). In addition to the previously characterized cations Se6I2 2+, SeI3 +, 1,1,4,4-Se4I4 2+, Se10 2+, Se8 2+, and Se4 2+, the NMR spectra of the equilibrium solution exhibited additional resonances the assignment of which has been carried out by 77Se-77Se COSY, selective irradiation experiments, and spectral simulation. Combining this information with the trends in the chemical shifts as well as with iodine, selenium, and charge balances that were calculated from quantitative integrated intensities, the presence of cyclic cations Se7[+ and 1,4-Se7I2 2+, as well as acyclic Se2I+, and 1,1,6,6-Se6I4 2+(two rotamers) could be inferred. Upon evaporation of the solvent only Se6I22+ was found to be present in the solid state.

Novel tellurium halides Te2Cl2 and Te2Br2

Novel Te2Cl2 and Te2Br2 were prepared by the reaction of Li2Te and TeX4 and characterized by mass spectroscopy and 125Te NMR spectroscopy, and by successful syntheses of 1,2-Te2S5 and 1,2-Te2Se5.

The Preparation of 1,2-Te2E5 (E = S, Se) from Tellurium Chloride Te2Cl2

A novel tellurium chloride Te2Cl2 has been prepared. Its application for the preparation of l,2-Te2Se5 and l,2-Te2S5 is described.

Novel Tellurium Halides

Tellurium reacts with SO2Cl2 in THF producing [HOC4H8][TeCl5(OC4H8)] (1a). In CS2 [H3O][Te3Cl13],·SO2 (2) is formed. When Me3SiBr or Me2SO is added to the reaction solution of 1a, [HOC4H8][TeBr5(OC4H8)] (1b) and [(Me2SO)2H]2[TeCl6] (3) are obtained, respectively. The reaction between metallic nickel, tellurium, and SO2Cl2 in acetonitrile produces [Ni(CH3CN)6][Te2Cl10] (4). All products are characterized by 125Te NMR spectroscopy and X-ray crystallography.

Selenium- and Tellurium-Containing Chalcogen Nitrides

The recent progress in the chemistry of electrically neutral selenium-and tellurium-containing chalcogen nitrides is reviewed. The synthetic and structural aspects of the eight-membered E4N4, six-membered E4N2, and E2N2 are described.