72643-40-4Relevant academic research and scientific papers
Synthesis of Pd(II) complexes of unsymmetrical, hybrid selenoether and telluroether ligands: Isolation of tellura-palladacycles by fine tuning of intramolecular chalcogen bonding in hybrid telluroether ligands
Gupta, Anand,Deka, Rajesh,Srivastava, Kriti,Singh, Harkesh B.,Butcher, Ray J.
, p. 95 - 103 (2019)
Two novel unsymmetrical selenoether ligands namely, N,N-dimethyl-2-(o-tolylselanyl)aniline (10) and 2-((2,6-dimethylphenyl)selanyl)-N,N-dimethylaniline (11) were synthesized from N,N-dimethylbenzylamine via the ortho-lithiation route. When ligands 10 and 11 were treated with Pd(COD)Cl2 (COD = 1,5-cyclooctadiene), the reaction afforded novel Pd(II) complexes of the form Pd(2-NMe2CH2C6H4)(R)SeCl2, where R = 2-MeC6H4 (16) and 2,6-MeC6H3 (17) respectively. Similarly, when unsymmetrical telluroether ligands, N,N-dimethyl-2-(phenyltellanyl)aniline (12), N,N-dimethyl-2-(o-tolyltellanyl)aniline (13), 2-((2,6-dimethylphenyl)tellanyl)-N,N-dimethylaniline (14) and 2-((2,6-diisopropylphenyl)tellanyl)-N,N-dimethylaniline (15), which contain one coordinating group with an sp3 N-donor atom, were treated with Pd(COD)Cl2, the palladium telluroether complexes of the form Pd(2-NMe2CH2C6H4)(R)TeCl2, where R = C6H5 (18), 2-MeC6H4 (19), 2,6-MeC6H3 (20) and 2,6-iPrC6H3 (21) respectively were obtained. The selenoether complexes 16 and 17 and telluroether complexes 18, 20 and 21 were characterized by single crystal X-ray diffraction studies. In the asymmetric unit of complex 18, two molecules are present and due to the presence of weak, intermolecular Te?Cl interactions, the two molecules exist as symmetrically related dimer. The N-donor substituents, which were involved in intramolecular chalcogen bonding (IChB) with the chalcogen atoms in the free ligand, made six-membered chelating rings in the complexes. Again, when bis(2-phenylazophenyl-C,N′)selenide 22 was treated with Pd(COD)Cl2, it afforded ortho C–H bond activated cyclopalladated complex 24. However, when bis(2-phenylazophenyl-C,N′)telluride 23 was treated with Pd(COD)Cl2, due to strong IChB from two N-donor substituents, the reaction afforded cleaved product, [2-(phenylazo)phenyl-C,N′]tellurenyl chloride, 25. All the metal complexes exhibited significant downfield chemical shifts in 77Se/125Te NMR spectra as compared to the corresponding free ligands. The downfield shifts in the 77Se/125Te NMR signal in the complexes might be attributed to the coordination of the chalcogen atoms to the electropositive Pd(II) center.
Isolation and structural characterization of some aryltellurium halides and their hydrolyzed products stabilized by an intramolecular Te...N interaction
Srivastava, Kriti,Shah, Poonam,Singh, Harkesh B.,Butcher, Ray J.
body text, p. 534 - 546 (2011/03/21)
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 SO 2Cl2 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, 10-14, 17, 19, 20-23, 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.
