Carboxylate free μ-oxo bridged ferric wheel with a record exchange coupling†
Abstract
A novel oxo-bridged, carboxylate free ‘ferric wheel’ was isolated with the molecular formula [FeIII8(μ-O)4(L2−)8] (1). Magnetic susceptibility measurements suggest that the Fe(III) ions are coupled antiferromagnetically and magnetic data modelling yields J1 = −26.4 cm−1, J2 = −170 cm−1 which are rationalized by DFT calculation. The exchange value for 1 of −170 cm−1 (Fe–O(oxo)–Fe) is the largest exchange value known compared to any homometallic or heterometallic wheel reported to date.