Spin Crossover in a Cobalt Complex on Ag(111)

Abstract

The (pypz)) 2 ] (py = pyridine, pz = pyrazole) deposited on Ag(111) was investigated with scanning tunneling microscopy at � 5 K. Due to a bis(tridentate) coordination sphere the molecules aggregate mainly into tetramers. Individual complexes in these tetramers undergo reversible transitions between two states with characteristic image contrasts when current is passed through them or one of their neighbors. Two molecules exhibit this bistability while the other two molecules are stable. The transition rates vary linearly with the tunneling current and exhibit an intriguing dependence on the bias voltage and its polarity. We interpret the states as being due to S = 1 / 2 and 3 / 2 spin states of the Co 2 + complex. The image contrast and the orders-of-magnitude variations of the switching yields can be tentatively understood from the calculated orbital structures of the two spin states, thus providing first insights into the mechanism of electron-induced excited spinstate trapping (ELIESST).

An iron(II) complex shows bistable spin-state switching characteristic with T1/2 centred at room temperature

“…Finally, the grand old phenomenon of SCO continues to evolve keeping abreast with the contemporary developments in molecular magnetism and related topics. 5,[28][29][30][31][32][33][34][35][36][37][38][39] We are happy that the topic has chosen us to express interesting facets, as discussed in this script.…”

Spin-Crossover and Fragmentation of Fe(neoim)2on Silver and Gold

“…We find that the complex remains intact and functional on the Ag(111) surface. In contrast to SCO complexes that involve H 2 B­(pyrazole)­(pyridylpyrazole)) 2 as tridendate ligands, ,, the present compound does not aggregate into oligomers and experiments can be carried out on isolated molecules. Spin-crossover may be induced via current injection from the tip of a scanning tunneling microscope (STM).…”

Spin‐Crossover Grafted Monolayer of a Co(II) Terpyridine Derivative Functionalized with Carboxylic Acid Groups

“…[ 24–29 ] Indeed, it has been proven that some nanostructured assemblies of SCO systems achieved in UHV can maintain their switching behavior even down to the sub‐monolayer and single‐molecule regime. [ 30–33 ] However, this deposition method is restricted to a few families of vacuum evaporable molecules. [ 34 ]…”

“…[24][25][26][27][28][29] Indeed, it has been proven that some nanostructured assemblies of SCO systems achieved in UHV can maintain their switching behavior even down to the sub-monolayer and single-molecule regime. [30][31][32][33] However, this deposition method is restricted to a few families of vacuum evaporable molecules. [34] An interesting alternative to extend the versatility of SCO is the deposition of properly functionalized molecules from solution to afford grafted monolayers.…”