Oxidation unzipping of stable nanographenes into joint spin-rich fragments.
When an all-benzenoid nanographene is linearly unzipped into oxygen-joined fragments, the oxidized benzenoid rings (aromatic sextets) selectively adopt the low-spin (DeltaS = 0) or high-spin conformation (DeltaS = 1) to yield the thermally most stable isomer. The selection of the conformation depends simply on the position of the aromatic sextets: the inner ones prefer the high-spin conformation, whereas the peripheral ones prefer the low-spin conformation. Therefore, the resulting most stable isomer has a total spin whose value equals the number of inner aromatic sextets (n(i)) along the oxidizing line. The nanographene fragments contained in this isomer have a ferromagnetic spin coupling. Due to the tautomerization between the high-spin and low-spin conformations, there also exist other possible isomers with higher energies and with spins at ground state ranging from 0 to (n(i) - 1). The rich geometrically correlated spins and the adjustable energy gaps indicate great potential of the graphene oxides in spintronic devices.
Gao
Xingfa
X
Department of Theoretical and Computational Molecular Science, Institute for Molecular Science, Myodaiji, Okazaki 444-8585, Japan.
Wang
Lu
L
Ohtsuka
Yuhki
Y
Jiang
De-en
DE
Zhao
Yuliang
Y
Nagase
Shigeru
S
Chen
Zhongfang
Z
D002244:Carbon / Q000737:chemistry*; D003198:Computer Simulation; D004583:Electrons; D006841:Hydrocarbons, Aromatic / Q000737:chemistry*; D007536:Isomerism; D008280:Magnetics; D008958:Models, Molecular; D008968:Molecular Conformation; D010084:Oxidation-Reduction; D010087:Oxides / Q000737:chemistry; D011789:Quantum Theory; D013696:Temperature
D006841:Hydrocarbons, Aromatic; D010087:Oxides; D002244:Carbon