Plutenko Maksym O, Shylin Sergii I, Shova Sergiu, Blinder Aleksander V, Fritsky Igor O
Department of Chemistry, Taras Shevchenko National University of Kyiv, 01601 Kyiv, Ukraine.
Department of Chemistry - Ångström Laboratory, Uppsala University, 75335, Uppsala, Sweden.
Acta Crystallogr E Crystallogr Commun. 2024 Jan 1;80(Pt 1):25-28. doi: 10.1107/S2056989023010514.
The synthetic availability of mol-ecular water oxidation catalysts containing high-valent ions of 3 metals in the active site is a prerequisite to enabling photo- and electrochemical water splitting on a large scale. Herein, the synthesis and crystal structure of di-ammonium {μ-1,3,4,7,8,10,12,13,16,17,19,22-dodeca-aza-tetra-cyclo-[8.8.4.1.1]tetra-cosane-5,6,14,15,20,21-hexa-onato}ferrate(IV) acetic acid tris-olvate, (NH)[Fe(CHNO)]·3CHCOOH or (NH)[Fe(-6H)]·3CHCOOH is reported. The Fe ion is encapsulated by the macropolycyclic ligand, which can be described as a dodeca-aza-quadricyclic cage with two capping tri-aza-cyclo-hexane fragments making three five- and six six-membered alternating chelate rings with the central Fe ion. The local coord-ination environment of Fe is formed by six deprotonated hydrazide nitro-gen atoms, which stabilize the unusual oxidation state. The Fe ion lies on a twofold rotation axis (multiplicity 4, Wyckoff letter ) of the space group 2/. Its coordination geometry is inter-mediate between a trigonal prism (distortion angle φ = 0°) and an anti-prism (φ = 60°) with φ = 31.1°. The Fe-N bond lengths lie in the range 1.9376 (13)-1.9617 (13) Å, as expected for tetra-valent iron. Structure analysis revealed that three acetic acid mol-ecules additionally co-crystallize per one iron(IV) complex, and one of them is positionally disordered over four positions. In the crystal structure, the ammonium cations, complex dianions and acetic acid mol-ecules are inter-connected by an intricate system of hydrogen bonds, mainly the oxamide oxygen atoms acting as acceptors.
活性位点含有三种金属高价离子的分子水氧化催化剂的合成可用性是实现大规模光催化和电化学水分解的先决条件。本文报道了二铵{μ-1,3,4,7,8,10,12,13,16,17,19,22-十二氮杂四环-[8.8.4.1.1]二十四烷-5,6,14,15,20,21-六酮酸根}高铁(IV)乙酸三溶剂合物，(NH₄)₂[Fe(C₁₂H₁₂N₁₂O₆)]·3CH₃COOH 或 (NH₄)₂[Fe(⁶-H)]·3CH₃COOH 的合成及晶体结构。Fe离子被大环多环配体包裹，该配体可描述为一个十二氮杂四环笼，带有两个封端的三氮杂环己烷片段，与中心Fe离子形成三个五元环和六个六元环交替的螯合环。Fe的局部配位环境由六个去质子化的酰肼氮原子形成，它们稳定了这种不寻常的氧化态。Fe离子位于空间群 2/的二重旋转轴上（多重性 4，Wyckoff 字母 ）。其配位几何形状介于三角棱柱（畸变角 φ = 0°）和反棱柱（φ = 60°）之间，φ = 31.1°。Fe-N键长在1.9376 (13)-1.9617 (13) Å范围内，这对于四价铁来说是预期的。结构分析表明，每一个铁(IV)配合物额外有三个乙酸分子共结晶，其中一个在四个位置上位置无序。在晶体结构中铵阳离子、配合物二价阴离子和乙酸分子通过复杂的氢键体系相互连接，主要是草酰胺氧原子作为受体。
