Mapping the spin states of surface deposited Fe(II) SCO Compounds by STM

We describe a novel method for analyzing the spin states of surface deposited Fe(II) spin crossover (SCO) compounds. The talk focuses on the investigation of $[FeII(L)_{2}](BF_{4})_{2}$ (L=2,6-di(1H-pyrazol-1-yl)-4-(thiocyanatomethyl)pyridine)$^1$ and the comparison to a high spin compound with a similar coordination motif. Single molecules and small clusters were investigated on HOPG. We were able to show a strong current contrast for the different spin states using the CITS technique. Changes of the spin state from high- to low-spin state and vice versa were observed at room temperature. Switching was statistically distributed, indicating a widening of the spin transition compared to the bulk state.$^{2}$ \newline $^{1}$ M. Haryono, et al., Eur. J. Inorg. Chem. 2009, 2136. \newline $^{2}$ M.S. Alam, et al., Angew. Chem. (2009) (accepted).