Figure 4: Energy profiles of possible mechanism.
From: Facile scission of isonitrile carbon–nitrogen triple bond using a diborane(4) reagent
Energy profiles of possible mechanism for the formation of 3–6 from 2 with relative Gibbs free energies in kcal mol−1 (estimated by optimization at the B3LYP/6-31G(d,p) level and subsequent single-point energy calculation at M06-2X/6-311+G(d,p) level with consideration of entropy contribution and solvent effect of benzene (conductor-like polarizable continuum model (CPCM)), all the compound numbers are in conjunction with Fig. 3). (a) Two possible pathways for the formation of 3 by reaction of 2 with CO (red: pathway through 8-O, blue: pathway through 9-O) (b) pathway for the formation of 4-6 by reaction of 2 with tBuNC (red: main pathway to 4-6, blue: branching to each of the compounds 4-6). (Remark: before the solvation correction, TS12-O is slightly higher than 11-O and TS14-N is slightly higher than 13-N in energy.)
