title: Stoichiometric and homogeneous-catalytic diboration of the n=n double bond of azobenzene.
abstract: The diboration of the N=N double bond of azobenzene was achieved by reaction of the [3]diboraplatinametalloarenophanes derived from ferrocene, [Fe(eta5-C5H4)B(NMe2)Pt(PEt3)2B(NMe2)(eta5-C5H4)], and bis(benzene)chromium, [Cr(eta6-C6H5)B(NMe2)Pt(PEt3)2B(NMe2)(eta6-C6H5)], with an excess of azobenzene in toluene at elevated temperature. The formation of the anticipated ansa-bis(boryl)hydrazines was substantiated by the determination of the molecular structure of the chromium derivative by X-ray diffraction. The synthesis of the ansa-bis(boryl)hydrazine derivative of ferrocene could also be accomplished under homogeneous catalysis conditions. Hence, reaction of the well-known [2]boraferrocenophane, [Fe(eta5-C5H4)2B2(NMe2)2], and azobenzene in the presence of 5 mol % [Pt(PEt3)3] afforded the bis-borylated hydrazine derivative in good yields.
authors.affiliation: Institut für Anorganische Chemie, Julius-Maximilians-Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany. h.braunschweig@mail.uni-wuerzburg.de
authors.forename: Holger
authors.initials: H
authors.lastname: Braunschweig
authors.forename: Thomas
authors.initials: T
authors.lastname: Kupfer
mesh_terms: D001391:Azo Compounds / Q000737:chemistry*; D001880:Boranes / Q000737:chemistry*; D002384:Catalysis; D009682:Magnetic Resonance Spectroscopy / Q000379:methods / Q000592:standards; D008958:Models, Molecular; D015394:Molecular Structure; D009584:Nitrogen / Q000737:chemistry*; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D012015:Reference Standards; D013237:Stereoisomerism
chemical_list: D001391:Azo Compounds; D001880:Boranes; D009942:Organometallic Compounds; C009850:azobenzene; D009584:Nitrogen