We present a comprehensive study of the heat capacity, crystal structures, DFT calculations, and magnetic and electrical properties of a one-dimensional(1D)rhodium(I)-semiquinonato complex,[Rh(3,6-DBSQ-4,5-(MeO)
2)(CO)
2]
∞(
3), where 3,6-DBSQ-4,5-(MeO)
2•- represents 3,6-di-
tert-butyl-4,5-dimethoxy-1,2-benzosemiquinonato radical anion. The compound
3 comprises neutral 1D chains of complex molecules stacked in a staggered arrangement with short Rh-Rh distances and exhibits unprecedented bistable multifunctionality with respect to its magnetic and conductive properties in the temperature range of 228-207 K. The observed bistability results from the thermal hysteresis across a first-order phase transition, and the transition accompanies the exchange of the interchain C-H…O hydrogen-bond partners between the semiquinonato ligands. The strong overlaps of the complex molecules lead to unusually strong ferromagnetic interactions in the low-temperature(LT)phase. Furthermore, the magnetic interactions in the 1D chain drastically change from strongly ferromagnetic in the LT phase to antiferromagnetic in the room-temperature(RT)phase with hysteresis. In addition, the compound
3 exhibits long-range antiferromagnetic ordering between the ferromagnetic chains and spontaneous magnetization because of spin canting(canted antiferromagnetism)at a transition temperature
TN of 14.2 K. The electrical conductivity of
3 at 300 K is 4.8×10
-4 S cm
-1, which is relatively high despite Rh not being in a mixed-valence state. The temperature dependence of electrical resistivity also exhibits a clear hysteresis across the first-order phase transition. Furthermore, the ferromagnetic LT phase can be easily stabilized up to RT by the application of a relatively weak applied pressure of 1.4 kbar, which reflects the bistable characteristics and demonstrates the simultaneous control of multifunctionality through external perturbation.
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