The reactions between bis(trifluoromethyl)amine and the boron halides: bis(trifluoromethyl)aminoboron dihalides

Abstract

Bis(trifluoromethyl)aminoboron dihalides, (CF₃)₂NBX₂(X = Cl or Br), have been prepared from the corresponding boron trihalides and bis(trifluoromethyl)amine, (CF₃)₂NH. These are the first trifluoromethylamino-derivatives of boron to be described. The analogous reaction involving boron tri-iodide gave boron trifluoride. CF₃NCF₂, and iodine. The aminoboron dihalides decomposed rapidly at room temperature in an atmosphere of nitrogen or under vacuum to give boron trifluoride and CF₃NCX₂. The new compound CF₃NCBr₂ was characterised by gas-phase molecular weight, mass spectrometry, and infrared spectroscopy. The reactions were followed by boron-11, fluorine-19, and proton magnetic resonance spectroscopy; tentative assignments are made for the reaction intermediates and it is suggested that the bis(trifluoromethyl)aminoboron dihalides are at least dimeric in solution.