Dibora[2]ferrocenophane: A Carbene‐Stabilized Diborene in a Strained cis‐Configuration. Issue 3 (20th December 2016)

• Record Type: Journal Article
• Authors: Braunschweig, Holger; Krummenacher, Ivo; Lichtenberg, Crispin; Mattock, James D.; Schäfer, Marius; Schmidt, Uwe; Schneider, Christoph; Steffenhagen, Thomas; Ullrich, Stefan; Vargas, Alfredo
• Is Part Of: Angewandte Chemie international edition. Volume 56:Issue 3(2017)
• Page Start: 889
• Page End: 892
• Publication Date: 2016-12-20
• Subjects: boron -- density functional calculations -- diborenes -- metallocenes -- strained molecules; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201609601
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: Unsaturated bridges that link the two cyclopentadienyl ligands together in strained ansa metallocenes are rare and limited to carbon–carbon double bonds. The synthesis and isolation of a strained ferrocenophane containing an unsaturated two‐boron bridge, isoelectronic with a C=C double bond, was achieved by reduction of a carbene‐stabilized 1, 1′‐bis(dihaloboryl)ferrocene. A combination of spectroscopic and electrochemical measurements as well as density functional theory (DFT) calculations was used to assess the influence of the unprecedented strained cis configuration on the optical and electrochemical properties of the carbene‐stabilized diborene unit. Initial reactivity studies show that the dibora[2]ferrocenophane is prone to boron–boron double bond cleavage reactions. Abstract : Bridge over troubled borons : A carbene‐stabilized diborene in an unprecedented cis ‐configuration was prepared by its incorporation into the ansa bridge of ferrocene. The dibora[2]ferrocenophane (see picture) is a rare example of an ansa metallocene with an unsaturated bridge and the first, whose multiple bond in the bridge is not based on carbon.