American Chemical Society
Browse
om1009022_si_001.pdf (5.03 MB)
Download file

Isolation and Structural Characterization of Some Aryltellurium Halides and Their Hydrolyzed Products Stabilized by an Intramolecular Te···N Interaction

Download (5.03 MB)
journal contribution
posted on 2011-02-14, 00:00 authored by Kriti Srivastava, Poonam Shah, Harkesh B. Singh, Ray J. Butcher
The isolation of pure [2-(phenylazo)phenyl-C,N′]tellurium(IV) tribromide (6) has been achieved by modifying the reported procedure, which involved transmetalation of [2-(phenylazo)phenyl-C,N′]mercury(II) chloride (7) with TeBr4. The mixed-valent derivative bis[2-(phenylazo)phenyl-C,N′]ditellurium dichloride (19), incorporating both a divalent and a tetravalent tellurium, was obtained serendipitously during the reduction of [2-(phenylazo)phenyl-C,N′]tellurium(IV) trichloride (16) with hydrazine hydrate. Bis[2-(phenylazo)phenyl-C,N′]telluride (10) has been synthesized by the ortho-lithiation route. Telluride 10, on treatment with SO2Cl2 and Br2, underwent oxidative addition to give the expected Te(IV) halogenated products bis[2-(phenylazo)phenyl-C,N′]tellurium(IV) dichloride (13) and bis[2-(phenylazo)phenyl-C,N′]tellurium(IV) dibromide (11), respectively. However, a similar reaction of 10 with I2 resulted in the formation of an unexpected telluronium cation, iodobis[2-(phenylazo)phenyl-C,N′]telluronium triiodide (14), and [2-(phenylazo)phenyl-C,N′]tellurenenyl(II) iodide (12). Alkaline hydrolysis of 16 under reflux conditions resulted in the formation of monomeric [2-(phenylazo)phenyl-C,N′]tellurinic acid (20) and its sodium salt (21) as a cocrystal. Bis[[2-(phenylazo)phenyl-C,N′]tellurium]oxide (22) was obtained from the hydrolysis of [2-(phenylazo)phenyl-C,N′]tellurium(II) chloride (17). The reaction of 13 with an alkaline solution resulted in the formation of the corresponding bis[2-(phenylazo)phenyl-C,N′]tellurium(IV) oxide (23) and dichlorobis[2-(phenylazo)phenyl-C,N′]tellurium(IV) oxide (24). The identity of all the derivatives was confirmed by multinuclear NMR (1H, 13C, 125Te) and FT-IR spectroscopy, elemental analysis, and ESI-MS. The structures for tellurium derivatives 6, 1014, 17, 19, 2023, and 23A were also confirmed by X-ray crystallography. Density functional theory (DFT) was utilized for optimizing the geometries of 11, 13, and 14 to examine the possibility of a four-membered intramolecular Te···N interaction.

History