The Density Functional Theory Account of Interplaying Long-Range Exchange and Dispersion Effects in Supramolecular Assemblies of Aromatic Hydrocarbons with Spin

Ana Maria Toader,Mihai V Putz,Maria Cristina Buta,Fanica Cimpoesu,Alice Mischie

doi:10.3390/molecules27010045

Ana Maria Toader, Mihai V Putz + Show 3 more

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https://doi.org/10.3390/molecules27010045

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Journal: Molecules	Publication Date: Dec 22, 2021
Citations: 2	License type: CC BY 4.0

Affiliation: West University of Timişoara

Abstract

Aromatic hydrocarbons with fused benzene rings and regular triangular shapes, called n-triangulenes according to the number of rings on one edge, form groundstates with n-1 unpaired spins because of topological reasons. Here, we focus on methodological aspects emerging from the density functional theory (DFT) treatments of dimer models of the n = 2 triangulene (called also phenalenyl), observing that it poses interesting new problems to the issue of long-range corrections. Namely, the interaction comprises simultaneous spincoupling and van der Waals effects, i.e., a technical conjuncture not considered explicitly in the benchmarks calibrating long-range corrections for the DFT account of supramolecular systems. The academic side of considering dimer models for calculations and related analysis is well mirrored in experimental aspects, and synthetic literature revealed many compounds consisting of stacked phenalenyl cores, with intriguing properties, assignable to their long-range spin coupling. Thus, one may speculate that a thorough study assessing the performance of state-of-the-art DFT procedures has relevance for potential applications in spintronics based on organic compounds.

Highlights

Received: 4 November 2021The field of stable carbon-based radicals [1,2] offers promises for the desiderata of spintronics with organic materials [3,4,5,6] and challenges in the fundamental respects of exotic bonding regimes [7]
The causal roots of special properties that are making polyaromatic hydrocarbons [8,9] and graphenes [10,11] interesting for materials sciences are common with the bonding factors tied under the heuristic concept of aromaticity [12,13].The delocalization implied by aromatic bonding determines functionalities such as reservoirs and conductors of charge [14,15,16] and spin [3,17].Triangulenes, i.e., condensed aromatic hydrocarbons with regular triangular geometry, are excellent objects for theoretical and experimental studies along the abovementioned desiderata
The spin distribution of the phenalenyl unit in unrestricted single determinant mode is different in the Hartree–Fock (HF) vs. Kohn–Sham (KS) comparison

Summary

Introduction

The field of stable carbon-based radicals [1,2] offers promises for the desiderata of spintronics with organic materials [3,4,5,6] and challenges in the fundamental respects of exotic bonding regimes [7]. The causal roots of special properties (conduction and magnetism) that are making polyaromatic hydrocarbons [8,9] and graphenes [10,11] interesting for materials sciences are common with the bonding factors tied under the heuristic concept of aromaticity [12,13].The delocalization implied by aromatic bonding determines functionalities such as reservoirs and conductors of charge [14,15,16] and spin [3,17].Triangulenes, i.e., condensed aromatic hydrocarbons with regular triangular geometry (spanning D3h point group), are excellent objects for theoretical and experimental studies along the abovementioned desiderata. [25], we analyzed the full landscape of singlet and triplet

Methods

Results

Conclusion