Monomere Phosphinoborane: Synthese eines Tetraalkylphosphinoborans und seine Umwandlung unter Retro- und Re-hydroborierung zu einem dimeren Phosphinoboran sowie Synthese eines Triphosphinoborans

Abstract The first monomeric tetralakylphosphinoborane t Bu 2 BP t Bu 2 was synthesized from t Bu 2 BBr and LiP t Bu 2 . It decomposes above −20°C via double retro-hydroboration and elimination of isobutene, undergoes subsequent re-hydroboration and dimerisation to give stable bis(phosphinoborane)[ i Bu(H)BP t Bu 2 ] 2 , whose molecular structure was determined by X-ray diffraction. It contains a planar, almost square (BP) 2 four-membered ring. The BP distances are 2.004(4)/2.022(4) A. The first monomeric triphosphinoborane, Me 2 PB(PMes 2 ) 2 , was synthesized similarly. All compounds have been characterized by NMR spectroscopy.