Antiferromagnetism in two-dimensional polyradical nanosheets

Abstract

2D polyradical nanosheets were prepared using interfacial polymerization and exhibited obvious antiferromagnetic behavior.

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

“…We consider three examples of TAM‐based 2D hex‐CORFs based on: a) ring‐sharing (rs) triphenylmethyl (TPM) radicals [ 9 ] ‐ TPM rs , b) ring‐sharing perchlorotriphenylmethyl (PTM) radicals [ 9 ] ‐ PTM rs , and c) acetylenic linked PTM radicals as found in a recently synthesized and experimentally characterized material (PTM acetylenic ) [ 10,11 ] (see Figure ). We note that although TPM rs and PTM rs have not yet been synthesized as extended materials, recently, it has been experimentally demonstrated that one can connect TPMs via ring‐sharing in molecules containing a ring of six αC centers (i.e., a TPM rs fragment).…”

“…[ 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. [ 9 ] Compared to the delocalized semimetallic state, the more stable AF and valence bond states have lower space group symmetries and thus can be described as emerging through symmetry breaking.…”

“…[ 9,13 ] The first experimental examples of a 2D hex‐CORF were indeed found to exhibit an AF ground state. [ 10,11 ] 2D hex‐CORFs can be seen as expanded graphene lattices where chemical linkers, rather than external strain, increase the distance between the threefold connected carbon sites. In this respect, 2D hex‐CORFs are similar to the hypothetical α‐graphyne [ 14 ] and α‐graphdiyne, [ 15 ] where the relatively increased distance between sp 2 carbon nodes leads to a reduction in the internode electronic coupling.…”

Conformational control over π-conjugated electron pairing in 1D organic polymers

“…35 There it has been shown that, in order to obtain a tunable electron pairing at room temperature via dihedral angle manipulation, the aC centres should be separated by a single aryl ring, 36 in line with previously reported trends for TAM dimers. 9,21 On the contrary, TAM 2D-COFs where radical centres are further away from each other, such as the recently synthesized materials, [45][46][47] show a persistent multi-radical conguration that is insensitive to aryl ring attening. 36 Based on these ndings, here we consider ring-sharing p-TAM polymers (Fig.…”

Controlling pairing of π-conjugated electrons in 2D covalent organic radical frameworks via in-plane strain

“…FM 26 – 28 or AFM 29 ) and diamagnetic quinoidal closed-shell solutions 30 , confirming that the electronic bi-stability from the bi-radical monomers persists in the resulting 2D materials. Recently, different examples of experimentally synthesised 2D-CORFs have been reported, exhibiting multi-radical electronic ground states with either AFM coupling 31 , 32 or weak coupling (i.e. paramagnetism) between spins 33 .…”