Séminaire - 10/06/2022 - Jan Patrick CALUPITAN -On-Surface Synthesis of Aza-Triangulene and Fused Derivatives

Invitation : Sylvain Clair (Département PHANO, Equipe Nano).

Diffusion : IM2NP, CINaM, Irphe, LP3 (via N. Sannier), Madirel (via P. Boulet), PIIM (via T. Angot), CPT (T. Martin), Fédération de Chimie (via S. Viel), CP2M

SEMINAIRE Vendredi 10 juin 2022 à 11h00

Salle des séminaires de l'Im2np, campus de Saint-Jérôme, 1er étage Bâtiment Poincaré

Jan Patrick CALUPITAN

Centro de Fisica de Materiales CFM/MPC

CSIC-UPV/EHU, San Sebastián, Espagne

On-Surface Synthesis of Aza-Triangulene and Fused Derivatives

The atomic precision afforded by on-surface synthesis (OSS) allows the doping of electronic structures by incorporation of heteroatoms into 2D π-magnetic carbon nanostructures. Herein, we report the OSS and characterization of N-doped triangulene, i.e. aza-triangulene (AzaT) [2], and its fused derivatives (fAzaTs). AzaT monomers were obtained from ketone-substituted triarylamine precursors by on-surface reduction followed by annealing and tip-induced manipulations. On Au(111), AzaT displays Kondo resonances consistent with electron transfer to the substrate and an open-shell triplet. Meanwhile, on Ag(111), electron transfer to AzaT results in a closed shell-structure. DFT calculations support these results, showing good agreement with experimentally-measured dI/dV and Kondo maps.[2] Increasing the coverage of the sample (> 80 %) and annealing to higher temperatures (T>300 C) resulted in formation of fused AzaT units. On Ag(111), this resulted in closed-shell structures while on Au(111), structures of different spin states (S=0,1/2,1) formed. The electronic fingerprints measured (dI/dV & Kondo maps) fit well with those predicted by DFT, revealing the dependence of spin state and its distribution on the bonding structure. Kondo-maps reveal localization of spin on some open-shell structures as predicted by DFT. This work demonstrates the tuning of electronic properties of N-doped π-magnetic structures by the substrate support and chemical bonding configuration.

References

[1] S. Song, et al. Chem. Soc. Rev., 2021, 3238-3262 (2021)

[2] T. Wang, et al. J Am. Chem. Soc. 50, DOI:10.1021/jacs.1c12618 (2022).