1-Naphthyl- and mesityltellurium(IV, II) derivatives of small bite chelating organic ligands: Effect of steric bulk and intramolecular secondary bonding interaction on molecular geometry and supr

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• 作者：Ashok K.S. Chauhan ; Anamika ; Arun Kumar ; Ramesh C. Srivastava ; R.J. Butcher ; Andrew Duthie
• 关键词：Sterically hindered organotelluriums ; Supramolecular association ; Intramolecular coordination ; Secondary bonding interactions
• 刊名：Journal of Organometallic Chemistry
• 出版年：2006
• 期刊代码：64_0022328x
• 类别：ch
• 出版时间：15 December 2006
• 卷：691
• 期：26
• 页码：5887-5894
• 文件大小：223 K

摘要

The synthesis and characterization of unsymmetric diorganotellurium compounds containing a sterically demanding 1-naphthyl or mesityl ligand and a small bite chelating organic ligand capable of 1,4-TeN(O) intramolecular interaction is described. The reaction of ArTeCl₃ (Ar = 1-C₁₀H₇, Np; 2,4,6-Me₃C₆H₂, Mes) with (SB)HgCl [SB = the Schiff base, 2-(4,4′-NO₂C₆H₄CHNC₆H₃-Me)] or a methyl ketone (RCOCH₃) afforded the corresponding dichlorides (SB)ArTeCl₂ (Ar = Np, g>1Aag>; Mes, g>1Bag>) or (RCOCH₂)ArTeCl₂ (Ar = Np; R = Ph (g>2Aag>), Me (g>3Aag>), Np (g>4Aag>); Ar = Mes, R = Ph (g>2Bag>)). Reduction of g>1Aag> and g>1Bag> by Na₂S₂O₅ readily gave the tellurides (SB)ArTe (Ar = Np (g>1Ag>), Mes, (g>1Bg>)) but that of dichlorides derived from methylketones was complicated due to partial decomposition to tellurium powder and diarylditelluride (Ar₂Te₂), resulting in poor yields of the corresponding tellurides g>2Ag>, g>2Bg> and g>3Ag>. Oxidation of the isolated tellurides with SO₂Cl₂, Br₂ and I₂ yielded the corresponding dihalides. All the synthesized compounds have been characterized with the help of IR, ¹H, ¹³C, and ¹²⁵Te NMR and in the case of g>2Aag>, and g>2Bag> by X-ray crystallography. Appearance of only one ¹²⁵Te signal indicated that the unsymmetric derivatives were stable to disproportionation to symmetric species. Intramolecular 1,4-TeO secondary bonding interactions (SBIs) are exhibited in the crystal structures of both the tellurium(IV) dichlorides, g>2Aag>, and g>2Bag>. Steric repulsion of the mesityl group in the latter dominates over lone pair–bond pair repulsion, resulting in significant widening of the equatorial C–Te–C angle. This appears to be responsible for the lack of TeCl involved supramolecular associations in the crystal structure of g>2Bag>.