Mixed-Valence Trimers in Organic–Inorganic Hybrid Chromium and Vanadium Chlorides

The crystal structures and basic magnetic properties of Prd 4 Cr 3 Cl 12 and Prd 4 V 3 Cl 12 (Prd = pyrrolidinium, C 4 H 10 N + ), previously unreported organic–inorganic hybrid compounds, are described. These compounds are synthesized via solid-state methods, and their crystal structures contain face-sharing [M 3 Cl 12 ] 4– trimers possessing the configuration M 3+ –M 2+ –M 3+ that are isolated from one another by pyrrolidinium cations. Magnetic analyses reveal that the dominant magnetic correlations for both materials are antiferromagnetic, with particularly strong coupling observed in Prd 4 V 3 Cl 12 . Neither compound exhibits long-range magnetic ordering down to 0.8 K, though sharp upturns in heat capacity data may signify the onset of such transitions.