Unsupported boron–carbon σ-coordination to platinum as an isolable snapshot of σ-bond activation

• Published in: Nature communications 2012-05, Vol.3 (1), p.872-872, Article 872
• Main Authors: Braunschweig, Holger, Brenner, Peter, Dewhurst, Rian D., Krummenacher, Ivo, Pfaffinger, Bernd, Vargas, Alfredo
• Format: Article
• Language: English
• Subjects: 639/638/263/406/77; 639/638/263/910; Boron - chemistry; Carbon - chemistry; Crystallography, X-Ray; Humanities and Social Sciences; Magnetic Resonance Spectroscopy; multidisciplinary; Platinum - chemistry; Science; Science (multidisciplinary)
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/ncomms1884

σ-Complexes of transition metals—key intermediates in metal-mediated bond activation and homogeneous catalysis—have traditionally been isolable only when chelating or when one of the participating atoms is hydrogen. Here, by treating the Lewis-basic transition metal complex [Pt(PEt 3 ) 4 ] with an electron-poor borirene, we isolate a complex with an unsupported borirene ligand bound, not through the unsaturated C=C bond, but exclusively via a B–C single bond. Using NMR spectroscopy, X-ray crystallography and density functional theory calculations, we show, herein, that coordination of the borirene ligand is based on electron donation from the B–C σ bond to the metal, aided by a strong Pt-to-B dative interaction. The complex is the first isolable non-agostic σ-complex featuring two p -block elements and has broad implications as a model for the metal-mediated activation of strong p -block- p -block σ-bonds. σ-Complexes of transition metals are key intermediates in metal-mediated bond activation, but have traditionally been isolable only when chelating or when one of the participating atoms is hydrogen. Here, a complex is isolated with an unsupported borirene ligand bound not through the unsaturated C=C bond, but exclusively via a B–C single bond.