Umpolung at Boron: Ancillary‐Ligand‐Induced Formation of Boron‐Based Donor Ligands from Phosphine‐Boranes. Issue 47 (22nd March 2018)

• Record Type: Journal Article
• Authors: Vondung, Lisa; Alig, Lukas; Ballmann, Monika; Langer, Robert
• Is Part Of: Chemistry. Volume 24:Issue 47(2018)
• Page Start: 12346
• Page End: 12353
• Publication Date: 2018-03-22
• Subjects: boron -- coordination modes -- density functional calculations -- iron -- umpolung; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201705847
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: Easy‐to‐prepare η 2 ‐coordinated phosphine‐borane ligands are demonstrated to liberate hydrogen upon treatment with different σ‐donor/π‐acceptor ligands (CO, t BuNC, CN − ). Depending on the utilized ancillary ligand, different reaction pathways are observed, ranging from simple hydride protonation to iron–boron bond formation and subsequent rearrangement to pincer‐type ligands based on a tricoordinate boron centre. The last‐named reactivity is in line with a formal umpolung at the boron centre from a Lewis acidic borane to a Lewis basic boron‐based donor ligand. Abstract : Letting go : An iron phosphine‐borane complex was shown to liberate hydrogen through different reaction pathways upon treatment with ancillary ligands. Depending on the nature of the ancillary ligand, the reaction either leads to a formal umpolung of the boron centre from a Lewis acid to a Lewis base or to deprotonation of the bis‐phosphine.