title: Electronic and structural effects of stepwise borylation and quaternization on borirene aromaticity.
abstract: Room-temperature photolysis of the aminoboryl complex [(OC)(5)Cr═B═N(SiMe(3))(2)] in the presence of a series of mono- or bis(boryl) alkynes bis{bis(dimethylamino)boryl}ethyne, 1-phenyl-2-bis(dimethylamino)borylethyne, and 1-trimethylsilyl-2-bis(dimethylamino)borylethyne led to the isolation of hitherto unknown borylborirenes in resonable yields, that is, [(RC═CR')(μ-BN(SiMe(3))(2))] (7, R = B(NMe(2))(2), R' = Ph; 8, R = R' = B(NMe(2))(2); 9, R = B(NMe(2))(2), R' = SiMe(3)). The borirenes were isolated and spectroscopically characterized by multinuclear NMR, IR, and UV/vis spectroscopy, crystallography, and elemental analysis. Reactivity studies of the borirenes demonstrated their behavior toward different Lewis bases. The isolated adducts and the parent borirenes were compared to 1,3-mesityl-2-phenylborirene and its adducts. To gain insight into the electronic structure and to evaluate the influence of the exocyclic groups, Density Functional Theory (DFT) calculations were carried out.
authors.affiliation: Institut für Anorganische Chemie, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany. h.braunschweig@uni-wuerzburg
authors.forename: Holger
authors.initials: H
authors.lastname: Braunschweig
authors.forename: Alexander
authors.initials: A
authors.lastname: Damme
authors.forename: Rian D
authors.initials: RD
authors.lastname: Dewhurst
authors.forename: Sundargopal
authors.initials: S
authors.lastname: Ghosh
authors.forename: Thomas
authors.initials: T
authors.lastname: Kramer
authors.forename: Bernd
authors.initials: B
authors.lastname: Pfaffinger
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Radacki
authors.forename: Alfredo
authors.initials: A
authors.lastname: Vargas
mesh_terms: D001896:Boron Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D004583:Electrons; D015394:Molecular Structure; D010782:Photolysis
chemical_list: D001896:Boron Compounds