Spin-crossover (SCO) systems are the focus of intense research due to their intrinsic behaviour as molecular-level switches. Such systems can change its spin state upon the effect of an external stimulus (i.e, temperature, pressure or electromagnetic radiation), which has profound effects over its electronic structure and physical properties. In this communication we present a systematic study of the performance of several density functional methodologies to study spin-crossover behaviour on first row transition metal complexes. Several functionals (OPBE, TPSSh, B3LYP, M062X and wB97xD) have been tested against a benchmark set of 21 mononuclear systems containing first row transition metal complexes (from chromium to nickel) and exhibiting spin-crossover. Among the tested functionals, the hybrid meta-GGA functional TPSSh provides with the best results across different metals and oxidation states and its performance in both predicting the correct ground state and the right energy window for SCO to occur is quite satisfactory. Although the functional performs with an overall error below 0.5 kcal/mol for our data set, such errors translate in large differences when computing transition temperatures for some of the studied systems. The reported methodology thus expands the use of the TPSSh functional to other metals and oxidation states other than FeII, making it the method of choice to study SCO in first row transition metal complexes.[1-4] Additionally, the presented results validate the potential use of the TPSSh functional for in silico screening of new molecules with SCO, or its use in the study of the electronic structure of such systems.[5] 1. K. P. Jensen, J. Cirera, J. Phys. Chem. A, 2009, 113(37), 10033 2. J. Cirera, F. Paesani, Inorg. Chem., 2012, 51(15), 8194 3. J. Cirera, E. Ruiz, Inorg. Chem., 2016, 55(4), 1657 4. J. Cirera, E. Ruiz, J. Mater. Chem. C, 2015, 3(30), 7954 5. J. Cirera, M. Via, E. Ruiz, submitted for publication (JCTC, 2017)

Benchmarking density functional methods for calculation of state energies of first row spin-crossover molecules

255th National Meeting (2018)

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