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.

中文翻译：

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稀有的八配位单核铁（III）自旋交联化合物：合成，晶体结构和磁性。

具有极高配位数的过渡金属配合物的化学性质引起人们的关注，因为它们在催化和生物系统中的应用。所述离子化四齿的配体去质子化6,6'-双（1- ħ -四唑-5-基）-2,2'-联吡啶[H ₂联吡啶（TTR）₂ ]中的铁（III）的存在下和四- Ñ溶液中的叔丁基溴化铵[ n -Bu ₄ N] Br导致合成了稀有的八配位阴离子单核络合物，即四正丁基铵双[6,6'-双（四唑-1-id-5-yl） ）-2,2'-联吡啶]铁（III）甲醇半溶剂化物二水合物，（C ₁₆ H ₃₆ N）[Fe（C ₁₂ H₆ N ₁₀）₂ ]·0.5CH ₃ OH·2H ₂ O或[ n- Bu ₄ N] [Fe {bipy（ttr）₂ } ₂ ]·0.5CH ₃ OH·2H ₂ O（1）通过元素分析，粉末X射线衍射（PXRD）和单晶X射线衍射对结构进行表征。在图1中，铁（III）离子的配位球是扭曲的双二蝶十二面体，其中八个配位被两个独立的四齿[bipy（ttr）₂ ] ^2-的八个N原子占据阴离子配体，因此形成阴离子[Fe {bipy（ttr）₂ } ₂ ] ^-单元，负电荷由游离的[ n -Bu ₄ N] ⁺阳离子平衡。对1的磁性能的研究表明，在150 K以下时，逐渐发生了不完全的自旋交叉行为。