Pnictogen Interactions with Nitrogen Acceptors

• Published in: Angewandte Chemie 2023-07, Vol.135 (28), p.n/a
• Main Authors: Lin, Binzhou, Liu, Hao, Karki, Ishwor, Vik, Erik C., Smith, Mark D., Pellechia, Perry J., Shimizu, Ken D.
• Format: Article
• Language: English
• Subjects: Catalysis; Chemistry; Electrostatic properties; Molecular Rotors; Nitro-Groups; Nitrogen; NMR; Non-Covalent Interaction; Nuclear magnetic resonance; Perturbation; Rotation; Rotational states; Rotors; Supramolecular Chemistry; π-Hole
• ISSN: 0044-8249; 1521-3757
• DOI: 10.1002/ange.202304960

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. Molecular rotors were designed to experimentally measure the transition state stabilizing abilities of nitrogen pnictogen interactions. The rotors formed intramolecular C=O⋅⋅⋅N interactions in the bond rotation transition states. Many common nitrogen functional groups were observed to form stabilizing interactions including amides, imines, and nitro groups.