第164回先端計測オープンセミナー

2022年11月28日 (月) 14:00 ~ 15:00

千現地区　研究本館8階中セミナー室 (811・812室) + オンライン (Zoom)
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Pavel Jelinek (Head of NANOSURF Lab / Institute of Physics of the CAS)

New perspectives in molecular magnetism: on-surface synthesis and SPM characterization

The recent progress in ultra-high vacuum on-surface synthesis enabled to form new molecular structures, which are not available by traditional organic chemistry in solution [1]. This progress combined with atomic-scale characterization by means of scanning probe microscopy opens new possibilities to study new magnetic molecular structures.

Recently a lot of attention was paid to synthesis of open shell polyaromatic hydrocarbons (PAH) showing interesting magnetic properties [2]. In this talk, we will provide a brief review of different strategies to introduce π-magnetism in PAHs including frustrated topology of bipartite lattice or electron-electron correlation [3]. We will present unpublished data reporting synthesis of polyradical molecules with strong multireference character. Their electronic structure is analyzed using SPM technique including nickelocene functionalized probes as well as DMRG and CAS calculations which enables to describe properly the multireference states.

In the second part, we introduce on-surface synthesis of 1D coordination π-d conjugated polymers, achieved by co-deposition of 2HQDI molecular precursor and various transition metals (Fe, Co, Ni, Cr, Cu) atoms on metal surfaces under UHV conditions [3]. This route results in formation of magnetic π-d organometallic polymers with length up to hundreds of nanometers [4]. We will demonstrate fully reversible multiconfigurational light-driven spin crossover switches in a single π-d organometallic Co-QDI chain suspended between two electrodes. The external light enables us to realize reversible spin cross over between low and high-spin states of individual cobalt centers within the chain.

References
[1]S. Clair and D. G. de Oteyza, Chemical Reviews 119, 4717 (2019).
[2]J.Li et al., Nature Communication 10, 200 (2019); N. Pavlicek et al., Nature Nanotechnology 12, 308 (2017); S. Mishra et al., Nature Nanotechnology 15, 22 (2019).
[3]V.M. Santhini et al, Angew. Chem. Int. Ed. 60, 439 (2021).
[4]Ch. Wackerlin et al, ACS Nano (2022) DOI: 10.1021/acsnano.2c05609