Scorpionates are facial chelates with predictable bonding patterns involving almost every metal ion on the periodic table. Heteroscorpionate variants of this chelate-class exhibit unique asymmetry in metal-complexes. The ligand Tp’ was created in our lab through simple triazole-for-pyrazole substitution and is now made efficiently by microwave heating. The present work describes Fe(Tp’)2 whose chiral cis-isomer was structurally confirmed by single crystal XRD. Solution and solid state magnetic measurements describe the well-defined spin crossover (SCO) of Fe(Tp’)2, a property modulated by the two large benzotriazole rings of the opposing Tp’ chelates. Fe(Tp’)2 is a thermally stable solid up to over 500 K; heating/cooling curves show a magnetic hysteresis of about 40 K. The intense orange color of Fe(Tp’) is assigned to MLCT transitions that are quenched at high temperatures. These MLCT are red shifted in the deep purple iron(III) form. M(Tp’)2 complexes offer new functionality to SCO systems including attachment points for heterogeneous supports and additional Lewis basicity because of the benotriazole rings. These features make Tp’-based complexes a fruitful area for applications of SCO in practical magnetic devices.

Rational design of iron-heteroscorpionates with spin crossover, chirality and Lewis basicity toward additional metal ions

ACS Spring Meeting 2021

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