Spin crossover (SC) compounds are a paradigmatic example of bistable materials. In such metal complexes the magnetic state can be tuned from a low-spin (LS) configuration into a low-lying meta-stable high-spin (HS) configuration through external stimuli. They have been postulated as bulk components for new generation memory devices and sensors.1 The most remarkable compounds have been obtained in the coordination chemistry of octahedral FeII, since the transition from diamagnetic S = 0 to paramagnetic S = 2 includes major changes in magnetism, electronic and spectroscopic properties, and even in size. When coordinated by triazole (trz) ligands, trz-bridged FeII 1D chains are formed with spin transition occurring over room temperature, and exhibiting wide thermal hysteresis cycles (&gt; 40 K), with those features easily tuned by functionalization of the trz or by substitution of the counter ions.2 Here we will report how further modifications in the trz ligands yield novel coordination FeII complexes with thermal hysteresis over 100 K in the solid state and around room temperature. We will also illustrate how these SC compounds can be incorporated into conducting networks to deliver multifunctional materials where the electrical conductivity exhibits also a memory effect, since the spin transition triggers a synergic switching in the transport properties (Figure 1).3 [1] A. Bousseksou et al. Chem. Soc. Rev. 2011, 40, 3313. [2] O. Kahn and C. J. Martínez, Science 1998, 279, 44. [3] Y. S. Koo and J. R. Galan-Mascaros, Adv. Mater. 2014, DOI: 10.1002/adma.201402579

Adventures in spin crossover phenomena: (Giant) memory effect in magnetic and in hybrid conducting materials

249th National Meeting (2015)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.