Spin Crossover in a Vacuum-Deposited Submonolayer of a Molecular Iron(II) Complex.
Spin-state switching of transition-metal complexes (spin crossover) is sensitive to a variety of tiny perturbations. It is often found to be suppressed for molecules directly adsorbed on solid surfaces. We present X-ray absorption spectroscopy measurements of a submonolayer of [Fe(II)(NCS)2L] (L: 1-{6-[1,1-di(pyridin-2-yl)ethyl]-pyridin-2-yl}-N,N-dimethylmethanamine) deposited on a highly oriented pyrolytic graphite substrate in ultrahigh vacuum. These molecules undergo a thermally induced, fully reversible, gradual spin crossover with a transition temperature of T1/2 = 235(6) K and a transition width of ΔT80 = 115(8) K. Our results show that by using a carbon-based substrate the spin-crossover behavior can be preserved even for molecules that are in direct contact with a solid surface.
†Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany.
Matthias
M
Bernien
‡Institut für Chemie, Technische Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany.
Dennis
D
Wiedemann
†Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany.
Christian F
CF
Hermanns
†Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany.
Alex
A
Krüger
†Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany.
Daniela
D
Rolf
§Department of Physics, Universität Erlangen-Nürnberg, Erwin-Rommel-Straße 1, 91058 Erlangen, Germany.
Wolfgang
W
Kroener
§Department of Physics, Universität Erlangen-Nürnberg, Erwin-Rommel-Straße 1, 91058 Erlangen, Germany.
Paul
P
Müller
‡Institut für Chemie, Technische Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany.
Andreas
A
Grohmann
†Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany.
Wolfgang
W
Kuch
N4 ligands; X-ray absorption spectroscopy; iron(II); magnetic molecules; monolayer; spin crossover; surfaces