Gerard Comas-Vila

Rationalizing Spin-Crossover Properties of Substituted Fe (II) Complexes We investigate spin-state transitions in a series of 24 [FeII(bppX)2]2+ spin-crossover (SCO) complexes using density functional theory (DFT). The TPSSh/def2-TZVP approach demonstrates reasonable accuracy in predicting spin-state energetics compared to other functionals, though significant deviations persist in transition temperature (T1/2) estimates. Temperature-dependent and quasi-harmonic corrections for low-frequency vibrational contributions to enthalpic and entropic terms yielded only marginal improvements. To improve T1/2 prediction accuracy, we develop electronic descriptors based on effective fragment orbitals (EFOs) and their occupations, quantifying ligand σ-donation and π-acceptor characteristics that govern ligand field strength. Additionally, we introduce a resonance descriptor (R) derived solely from the effective atomic orbitals (eff-AOs) of isolated ligands. Our analysis reveals that electron-donating groups (EDGs) enhance π-electron density in the ligands while simultaneously reducing both σ-donor and π-acceptor capabilities, ultimately lowering the T1/2 value. These descriptors perform reasonably well also for a set of 12 [FeII(pyboxX)2]2+ SCO complexes. This new methodology provides a computationally efficient framework for modulating spin-state properties in transition metal complexes, enabling rational design of SCO materials.

Our last work is online in @InorgChem. We rationalize spin-crossover properties of substituted Fe (II) complexes pubs.acs.org/doi/10.1021/...

Rationalizing Spin-Crossover Properties of Substituted Fe (II) Complexes | Inorganic Chemistry pubs.acs.org/doi/10.1021/...
Comas-Vilà and Salvador @InorgChem #iron #SCO #DFT #EFOs #effAOs #EDGs

My second @chemistryworld.com story is online 🥰 !
Really enjoyed delving into the realm of computational chemistry 💻 and working on this piece! With amazing help from the authors Pedro Salvador and Gerard Comas-Vilà, external expert @ampendas.bsky.social, and editor @jennifernewton.bsky.social.

Bridging the gap between Hammett parameters and the electronic structure of aromatic systems Occupation of effective atomic orbitals used to quantify and predict Hammett parameters

By linking electronic structure to inductive and resonance effects, a new framework can help quantify inductive and resonance effects exerted by substituents in aromatic systems, letting chemists more accurately predict Hammett parameters. #ChemSky