Exploring the computational design of anionic spin-crossover systems

Abstract

In this work, a systematic study on how the ligand design in the anionic spin-crossover system [Fe(OEt-L1-pH)(NCS)3]− can be used to achieve a high degree of tuning of its transition temperature (T1/2) is presented. Our calculations correctly reproduce the experimentally reported data and allow us to gain further and systematic insight on how to tune up or down the T1/2 value. The axial thiocyanate ligand can be replaced by similar groups (NCO−, NCSe− and NCBH3−) that allows for a large change in the T1/2 value, while a much finer degree of tuning can be achieved by functionalizing the para position of the pyridine groups. Altogether, [Fe(OEt-L1-pH)(NCS)3]− offers a unique platform to explore how ligand design can be realized to prepare new anionic SCO materials with tailored properties.