title: From Stiba- and Bismaheteroboroxines to N,C,N-Chelated Diorganoantimony(III) and Bismuth(III) Cations-An Unexpected Case of Aryl Group Migration.
abstract: 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](-) 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 4-9 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]·(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.
authors.forename: Libor
authors.initials: L
authors.lastname: Dostál
authors.forename: Roman
authors.initials: R
authors.lastname: Jambor
authors.forename: Aleš
authors.initials: A
authors.lastname: Růžička
authors.forename: Robert
authors.initials: R
authors.lastname: Jirásko
authors.affiliation: §Research Institute for Organic Syntheses, Rybitví 296, CZ 533 54 Pardubice, Czech Republic.
authors.forename: Antonín
authors.initials: A
authors.lastname: Lyčka
authors.affiliation: ∥Institut für Anorganische Chemie, Universität Bremen, Leobener Straße, 28359 Bremen, Germany.
authors.forename: Jens
authors.initials: J
authors.lastname: Beckmann
authors.affiliation: ⊥G.A.Razuvaev Institute of Organometallic Chemistry, RAS, 49 Tropinin Street, 603950 Nizhny Novgorod, Russian Federation.|#N.I. Lobachevsky Nizhny Novgorod State University, Gagarin Avenue 23, 603950 Nizhny Novgorod, Russian Federation.
authors.forename: Sergey
authors.initials: S
authors.lastname: Ketkov