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Updated: Jan 20, 2026
Crystal Field Theory - Octahedral Complexes
Temperature-Induced Single-Crystal-to-Single-Crystal Transformations with Consequential Changes in the Magnetic
Amit Adhikary1, Sohel Akhtar1, Anand Pariyar2
1School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A &2B, Raja S. C. Mullick Road, Kolkata 700032, West Bengal, India.
Abstract:
The present article deals with an one-to-one structure-property correspondence of a dinuclear iron complex, [Dipic(H2O)FeOH]2·H2O (1) (Dipic = pyridine-2,6-dicarboxylic acid). Variable-temperature X-ray single-crystal structural analysis confirms a phase transition of complex 1 to complex 2 ([Dipic(H2O)FeOH]2) at 120 °C. Further, single-crystal-to-single-crystal (SCSC) transformation was monitored by temperature-dependent single crystal X-ray diffraction, powder X-ray diffraction, time-dependent Fourier-transform infrared spectroscopy, and differential scanning calorimetry. SCSC transformation brings the change in space group of single crystal. Complex 1 crystallizes in the C2/c space group, whereas complex 2 crystallizes in the Pi̅ space group. SCSC transformation brings the change in packing diagram as well. Complex 1 shows two-dimensional network through H-bonding, whereas the packing diagram of complex 2 shows a zigzag-like arrangement. Phase transformation not only fetches structural changes but also in the magnetic properties. Difference in Fe-O-Fe bond angles of two complexes creates notable variation in their antiferromagnetic interactions with adjacent metal centers.
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