Tip-induced nitrene generation

TL;DR

This study demonstrates the tip-induced formation of a molecule with three nitrene centers on a surface, revealing its magnetic properties and potential as a high-spin molecular system.

Contribution

It introduces a method to generate and characterize a molecule with multiple nitrene centers on a surface, combining experimental microscopy with theoretical calculations.

Findings

Formation of trinitreno-s-heptazine with three nitrene centers.

Ferromagnetic coupling suggests a high-spin ground state.

Surface environment influences the molecule's electronic state.

Abstract

We generated trinitreno-s-heptazine, a small molecule featuring three nitrene centers, by tip-induced chemistry from the precursor 2,5,8-triazido-s-heptazine on bilayer NaCl on Au(111). The precursor's azide groups were dissociated to form mono-, di- and trinitreno-s-heptazine, yielding molecules with one to three nitrene centers. The precursor and its products are characterized by atomic force microscopy and scanning tunnelling microscopy. Broken-symmetry DFT and configuration interaction calculations of inter- and intra-nitrene exchange couplings suggest a ferromagnetic coupling of the S = 1 nitrene centers, resulting in a high-spin septet ground state for neutral trinitreno-s-heptazine in the gas phase. On bilayer NaCl on Au(111), the combined results of experiments and theory suggest trinitreno-s-heptazine to be an anion with a sextet ground state.