nl0c02939_si_001.pdf (8.37 MB)
Atomically Precise Synthesis and Characterization of Heptauthrene with Triplet Ground State
journal contribution
posted on 2020-08-07, 10:44 authored by Xuelei Su, Can Li, Qingyang Du, Kun Tao, Shiyong Wang, Ping YuBy virtue of multitunable
spin structures upon designing the π-electron
topologies, phenalenyl-based nanographenes are of substantial interest
in fundamental science and for potential applications in spintronics.
Heptauthrene, as one of the well-known phenalenyl diradicals, is composed
of one benzene-fused bisphenalenyls in mirror symmetry
and expected to have a triplet ground state. However, the synthesis
of unsubstituted heptauthrene remains very challenging due to the
high reactivity of triplet diradicals. Here, we report a combined
in-solution and on-surface synthesis of unsubstituted heptauthrene,
whose chemical structure is characterized through bond-resolved atomic
force microscopy. Combined with mean-field Hubbard model calculations,
its triplet ground state is unambiguously confirmed by the underscreened
Kondo resonance in response to the magnetic field, as well as the
engineered spin-state switching upon extra hydrogen atom addition
and dissociation on the radical site. Our results provide access to
phenalenyl-based nanographenes with high-spin ground state, potentially
useful in constructing high-spin networks.