Molecular hydrogen tweezers: structure and mechanisms by neutron diffraction, NMR, and deuterium labeling studies in solid and solution.

摘要: The mechanism of reversible hydrogen activation by ansa-aminoboranes, 1-N-TMPH-CH2-2-[HB(C6F5)2]C6H4 (NHHB), was studied neutron diffraction and thermogravimetric mass-spectroscopic experiments in the solid state as well with NMR FT-IR spectroscopy solution. structure ansa-ammonium borate NHHB determined scattering, revealing a short N–H···H–B dihydrogen bond 1.67 A. Moreover, this intramolecular H–H distance solution to be also 1.6–1.8 A 1H spectroscopic T1 relaxation 1D NOE measurements. X-ray B–H N–H distances deviated from calculated values. dynamic nature molecular tweezers additionally multinuclear variable-temperature spectroscopy. We synthesized stable, individual isotopic isomers NDDB, NHDB, NDHB. measurements revealed primary isotope effect chemical shift difference pΔ1H(D) = δ(NH) – δ(ND) (0.56 ppm), hence supported bond...