Design of multi-functional 2D open-shell organic networks with mechanically controllable properties

Abstract

Controlling spin localization, structure, electronic energy levels and magnetic interactions in a flexible open-shell 2D organic framework by external mechanical strain.

Existence of multi-radical and closed-shell semiconducting states in post-graphene organic Dirac materials

“…In the perfectly planar GY and GDY, such a mechanism does not exist and, hence, the fully hexagonal symmetric delocalised solution prevails over the quinoidal state. This structure-electronic relationship between aryl ring twist angles and localisation/delocalisation of electrons, previously found for the analogous single-molecules 56 , could represent a symmetry breaking tool with which to mechanically induce electron pairing by external strains 57 or, also, to spatially detect paired π -electrons by identifying particularly planarized aryl rings. The quinoidal solution is found to lay 27 meV and 133 meV below the semimetallic solution for GP and GDP, respectively (see Fig.…”

2D Hexagonal Covalent Organic Radical Frameworks as Tunable Correlated Electron Systems

“…Previously, we have confirmed that the interlinked electronic and structural properties of individual TAMs can be well captured by DFT‐based calculations. [ 20 ] Building on previous work, [ 8,9 ] we further confirm that the properties of TAM‐based 2D hex‐CORFs can be well captured by suitable DFT calculations, and thereby show how their electronic states can be tuned by compression. DFT is a formally exact method [ 21 ] to determine the electron density of quantum systems without the need for an explicit many body treatment.…”

“…Recently, we proposed a new class of sp 2 carbon‐based SL materials based on linking trivalent triarylmethyl (TAM) αC‐containing radical molecules to form 2D covalent organic radical frameworks (CORFs). [ 8,9 ] Since our prediction, some example 2D CORFs have been experimentally prepared. [ 10–12 ] Herein, we focus on 2D CORFs with hexagonal connectivity based on the graphene‐like honeycomb lattice (2D hex‐CORFs), which we predicted to exhibit spin‐polarized antiferromagnetic (AF) ground states and low energy valence bond quinoidal gapped states, linked by an intervening semimetallic transition state.…”

Pairing-up viologen cations and dications: a microscopic investigation of van der Waals interactions

“…Organic-based radicals have attracted much attention due to their ubiquitous character, being capable to act as spin holders, 1 switchable materials 2,3 and binding ligands, 4 not to mention their ability to form three dimensional networks. 5 From their flexible electronic structure, unusual properties including conductivity, magnetism, spin crossover or charge ordering have been observed and stimulated intensive work. [6][7][8][9][10][11] Furthermore, changes in the spin states can be controlled by manipulating the unpaired electrons, taking advantage of their intrinsic degree of freedom.…”