Aminoboratabenzenes. An Evaluation of the Exocyclic B−N Interaction
作者:Arthur J. Ashe、Jeff W. Kampf、Christian Müller、Manuela Schneider
DOI:10.1021/om9506330
日期:1996.1.9
The reaction of 1-chloro-1-boracyclohexa-2,5-diene with diisopropylamine or N-benzyl-N-methylamine followed by reaction with LDA in THF affords lithium N,N-diisopropyl-1-aminoboratabenzene (9b) or lithium N-benzyl-N-methyl-1 -aminoboratabenzene (9c), respectively. The reaction of 9b with FeCl2 affords bis(N,N-diisopropyl-1-aminoboratab enzene)iron (18b), while the reaction of 9b or 9c with Mn(CO)(3)(CH3CN)(3)PF6 affords tricarbonyl[N,N-diisopropyl-1-aminoboratabenzene)manganese (19b) or tricarbonyl-1-(N-benzyl-N-methylamino) boratabenzene manganese (19b), respectively. Photochemical displacement of CO by PMe(3) from 19b affords dicarbonyl(trimethylphosphine) (N-benzyl-N-methyl-1-aminoboratabenzene)manganese (20b). The rates of bond rotation about the B-N bonds of 9c, 18b, 19b,c, and 20b have been determined using variable-temperature NMR spectroscopy. The rates depend markedly on the electron-withdrawing power of the coordinating metal group. The boron atom is weakly coordinated to manganese (B-Mn = 2.485(3) Angstrom) and strongly bound to nitrogen (B-N = 1.417 (3) Angstrom).