From Stiba- and Bismaheteroboroxines to N,C,N-Chelated Diorganoantimony(III) and Bismuth(III) Cations鈥擜n Unexpected Case of Aryl Group Migration

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• 作者：Libor Dost谩l ; Roman Jambor ; Ale拧 R暖啪i膷ka ; Robert Jir谩sko ; Anton铆n Ly膷ka ; Jens Beckmann ; Sergey Ketkov
• 刊名：Inorganic Chemistry
• 出版年：2015
• 出版时间：June 15, 2015
• 年：2015
• 卷：54
• 期：12
• 页码：6010-6019
• 全文大小：558K
• ISSN：1520-510X

文摘

An unprecedented transfer of an aryl group from boron to Sb and Bi is observed in the reaction of heteroboroxines of general formula ArM[(OBR)₂O] [where M = Sb, Bi; Ar = C₆H₃-2,6-(CH₂NMe₂)₂; R = Ph, 4-CF₃C₆H₄, 4-BrC₆H₄] with corresponding boronic acid RB(OH)₂. Using this procedure, ion pairs [ArMR]⁺[R₄B₅O₆]^{鈭?/sup> were obtained [where M = Sb and R = Ph (4), 4-CF₃C₆H₄ (5), 4-BrC₆H₄ (6); where M = Bi and R = Ph (7), 4-CF₃C₆H₄ (8), 4-BrC₆H₄ (9)]. All compounds were characterized using elemental analysis, electrospray ionization mass spectrometry, and multinuclear NMR spectroscopy, and molecular structures of 4 and 7 were determined by single-crystal X-ray diffraction analysis. The central metal atoms in 4鈥?b>9 were arylated by respective boronic acids, which represents, to the best of our knowledge, unprecedented reaction path in the chemistry of heavier group 15 elements. Investigation of the mechanism of this transformation indicated that Lewis pairs consisting of monomeric oxides ArMO and boroxine rings are probably key intermediates. In this regard, molecular structures of ArSbO[(4-CF₃C₆H₄)₃B₃O₃]路(4-CF₃C₆H₄)B(OH)₂ (10) and {ArSbO[(3,5-(CF₃)₂C₆H₃)₃B₃O₃]} (13) were established by single-crystal X-ray diffraction analysis, and compound 13 was also fully characterized in solution by multinuclear NMR spectroscopy. The bonding in 13 was analyzed in detail by using density functional theory and natural bond order calculations and compared with known adduct ArSbOB(C₆F₅)₃ (14) and hypothetical ArSbO monomer.}