Pnictogen Interactions with Nitrogen Acceptors

Abstract

Stabilizing nitrogen pnictogen bond interactions were measured using molecular rotors. Intramolecular C=O•••N interactions were formed in the bond rotation transition states which lowered the rotational barriers and increased the rates of rotation, as measured by EXSY NMR. The pnictogen interaction energies show a very strong correlation with the positive electrostatic potential on nitrogen, which was consistent with a strong electrostatic component. In contrast, the NBO perturbation and pyramidalization analyses show no correlation, suggesting that the orbital-orbital component is minor. The strongest C=O•••N pnictogen interactions were comparable to C=O•••C=O interactions and were stronger than C=O•••Ph interactions, when measured using the same N-phenylimide rotor system. The ability of the nitrogen pnictogen interactions to stabilize transition states and enhance kinetic processes demonstrates their potential in catalysis and reaction design.

Structural Elucidation of N2O Clusters at Low Temperatures: Exemplary Framework Stabilized by π-Hole-Driven N···O and N···N Pnicogen Bonding Interactions

“…A number of studies recognized nitrogen as a positive center with pnicogen character theoretically in the literature too. 61 −67 In addition to our group, experimental evidence of nitrogen harboring a pnicogen bond was provided by Puzzarini and coworkers 68 using rotational spectroscopy, and Lin et al 66 using EXSY NMR with ab initio computational support. The presence of an N•••N pnicogen bond with dual N•••Se chalcogen bonds in 5,6-dichloro-2,1,3-benzoselenadiazole homodimers was reported quite recently.…”

“…A subtle pnicogen character of NH 3 (not driven either by σ-hole or π-holes) was also established in the PCl 3 –NH 3 and CO 2 –NH 3 dimer systems. A number of studies recognized nitrogen as a positive center with pnicogen character theoretically in the literature too. − …”