Hydrogen Activation by a σσ*-Carbene Through Quantum Tunneling.

ABSTRACT: The electronic structure of carbenes arises from the occupation of a σ and a π frontier orbital. While parent methylene possesses a triplet ground state (σ¹π¹), substituents are capable of stabilizing the singlet as the ground state (σ²π⁰ or σ⁰π²) by altering the frontier orbital energies. Here, we reveal that the 1,2[I]-shift isomer of 2-iodopyridine, the N-iodo Hammick intermediate, features a resonance between its carbene σ and N-I bond σ* orbitals, rendering them frontier orbitals. This singlet carbene is efficiently generated via UV photolysis of 2-iodopyridine in solid neon at 4.4 K and reacts with molecular hydrogen - but not deuterium - via N-I bond cleavage enabled by quantum tunneling. Instanton theory compu

SUBMITTER: Bhagat V 

PROVIDER: S-EPMC12498415 | biostudies-literature | 2025 Oct

REPOSITORIES: biostudies-literature