Homologous Series of Heavier Element Dipnictenes 2,6-Ar2H3C6E=EC6H3-2,6-Ar2 (E = P, As, Sb, Bi; Ar = Mes = C6H2-

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• 作者：Brendan Twamley ; Chadwick D. Sofield ; Marilyn M. Olmstead ; and Philip P. Power
• 刊名：Journal of the American Chemical Society
• 出版年：1999
• 出版时间：April 14, 1999
• 年：1999
• 卷：121
• 期：14
• 页码：3357 - 3367
• 全文大小：195K
• 年卷期：v.121,no.14(April 14, 1999)
• ISSN：1520-5126

文摘

The synthesis and characterization of several m-terphenyl heavier main group 15 (P, As, Sb, or Bi)dihalides, together with their reduction to give a homologous series of double-bonded dipnictenes, are reported.Reaction of LiC₆H₃-2,6-Mes₂ (Mes = C₆H₂-2,4,6-Me₃) or LiC₆H₃-2,6-Trip₂ (Trip = C₆H₂-2,4,6-ⁱPr₃) with theappropriate trihalide affords 2,6-Mes₂H₃C₆ECl₂ (E = As, 1; Sb, 2; Bi, 3) and 2,6-Trip₂H₃C₆ECl₂ (E = P, 4;As, 5; Sb, 6; Bi, 7). The compounds 1-7 were characterized by ¹H and ¹³C NMR spectroscopy as well as by³¹P NMR spectroscopy in the case of 4. In addition, the structures of 3, 5, and 6 were determined. Reductionof the phosphorus species 4 with potassium in hexane gives a mixture of the diphosphene 2,6-Trip₂H₃C₆P=PC₆H₃-2,6-Trip₂, 12, and the phosphafluorene species, 1-(2,4,6-triisopropylphenyl)-5,7-diisopropyl-9-phosphafluorene, 11. The compound 11, which results from the insertion of a phosphorus into a C(Ar)-C(i-Pr)bond was synthesized in higher yield by the reduction of 4 with magnesium. The simple reduction of 1-4, 6,and 7 with potassium, and of 5 with magnesium, yielded the new series of dipnictenes, 2,6-Mes₂H₃C₆E=EC₆H₃-2,6-Mes₂ (E = As, 8; Sb, 9; Bi, 10) and 2,6-Trip₂H₃C₆E=EC₆H₃-2,6-Trip₂ (E = P, 12; As, 13; Sb, 14a; Bi,15), as well as the partially reduced species 2,6-Trip₂H₃C₆(Cl)SbSb(Cl)C₆H₃-2,6-Trip₂ (14b). The compounds,which displayed high thermal stability, were characterized by ¹H, ¹³C, and ³¹P NMR and UV-vis spectroscopy.The structures of 8-11, 13, 14a, and 14b were determined. These compounds constitute the first homologousseries of dipnictene structures for all the heavier group 15 elements. The E-E bond shortenings observed forthe heaviest antimony or bismuth derivatives lead to the conclusion that overlap is quite important in thefifth- and sixth-period elements of this group.