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Updated: Dec 10, 2025
Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses
Published on: June 7, 2018
A rare octacoordinated mononuclear iron(III) spin-crossover compound: synthesis, crystal structure and magnetic
Xiaoyun Hao1, Tong Cao1, Yong Dou1
1College of Chemical and Chemical Engineering, Shandong University of Technology, Zibo 255049, People's Republic of China.
Abstract:
The chemistry of transition-metal complexes with unusually high coordination numbers has been of interest because of their application in catalytic and biological systems. Deprotonation of the ionogenic tetradentate ligand 6,6'-bis(1H-tetrazol-5-yl)-2,2'-bipyridine [H2bipy(ttr)2] in the presence of iron(III) and tetra-n-butylammonium bromide, [n-Bu4N]Br, in solution resulted in the synthesis of a rare octacoordinated anionic mononuclear complex, tetra-n-butylammonium bis[6,6'-bis(tetrazol-1-id-5-yl)-2,2'-bipyridine]iron(III) methanol hemisolvate dihydrate, (C16H36N)[Fe(C12H6N10)2]·0.5CH3OH·2H2O or [n-Bu4N][Fe{bipy(ttr)2}2]·0.5CH3OH·2H2O (1), which has been structurally characterized by elemental analysis, powder X-ray diffraction (PXRD) and single-crystal X-ray diffraction. In 1, the coordination sphere of the iron(III) ion is a distorted bis-disphenoid dodecahedron, in which the eight coordination positions are occupied by eight N atoms from two independent tetradentate [bipy(ttr)2]2- anionic ligands, therefore forming the anionic [Fe{bipy(ttr)2}2]- unit, with the negative charge balanced by a free [n-Bu4N]+ cation. An investigation of the magnetic properties of 1 revealed a gradual incomplete spin-crossover behaviour below 150 K.
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