Steric isotope effects gauged by the bowl-inversion barrier in selectively deuterated pentaarylcorannulenes.

摘要: Motivated by a greater bowl depth and barrier to inversion in sym-1,3,5,7,9-pentamanisylcorannulene compared corannulene, an experimental plan is developed measure the effective hydrogen/deuterium steric kinetic isotope effect (KIE). Symmetry arguments are used design orthogonal labeling patterns so that for CD3 compound can be measured presence of CH3 compound. This scheme eliminates differential uncertainty temperature measurement allowing both barriers same sample, which turn reduces error determining barrier. Ab initio computations corroborate structure found experimentally. The predicted determined KIE at 250 K 1.08 (modified QUIVER M06-2X/cc-pVDZ) 1.22 ± 0.06 (VT-NMR), respectively. results stem from differences zero-point energy CH CD motions; however, phenomenology makes group appear effectively “stickier” than CH3....