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首页> 外文期刊>Dalton transactions: An international journal of inorganic chemistry >Synthesis, structures and magnetic properties of polynuclear mixed-valence (MnMnIII)-Mn-II complexes containing 3-(2-phenol)-5-(pyridin-2-yl)-1,2,4-triazole ligand
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Synthesis, structures and magnetic properties of polynuclear mixed-valence (MnMnIII)-Mn-II complexes containing 3-(2-phenol)-5-(pyridin-2-yl)-1,2,4-triazole ligand

机译：含3-（2-苯酚）-5-（吡啶-2-基）-1,2,4-三唑配体的多核混合价（MnMnIII）-Mn-II配合物的合成，结构和磁性

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摘要

This paper reports the synthesis, crystal structures, and magnetic properties of a series of mixed-valence polynuclear manganese complexes bridged by a dianionic 1,2,4-triazole-based ligand L2- (H2L = 3-(2-phenol)-5-(pyridin-2-yl)-1,2,4-triazole). Complexes 1 to 3 show a similar binuclear structure, with the central core of [(MnMnIII)-Mn-II(L)(2)] and some other small molecules also coordinated to the two Mn centers. The two [(MnMnIII)-Mn-II(L)(2)] subunits can be further connected by different dicarboxylic acids to construct non-charged tetranuclear complexes 4 to 7. In these complexes, each deprotonated dianionic ligand L2- acts as a mu(2)-bridged ligand to coordinate two Mn centers via the 1,2,4-triazole ring. Bond valence sum (BVS) calculations and Mn surrounding bond lengths indicate that the Mn center coordinated to the pyridine N atoms in the +2 oxidation state, while another Mn center coordinated to the phenolic O atoms is in the +3 oxidation state. The Mn-III centre shows Jahn-Teller elongation along one of the axes. Magnetic studies show the presence of ferromagnetic Mn-III-Mn-II coupling in the binuclear (1-3) and tetranuclear (4-7) complexes with the magnetic coupling constant (J) ranging from 0.58 to 1.17 cm(-1), based on the Hamiltonian H = -2JS(1).S2 (S-1 = 5/2 and S-2 = 2). In all cases both z'J' (intermolecular interactions) and D parameter (Zero Field Splitting of the Mn (III) ion) has been introduced to improve the corresponding fit. The relationship of the coupling interaction between the Mn-II/Mn-III and their electronic structures is discussed.
机译：本文报道了一系列由二价1,2,4-三唑基配体L2-（H2L = 3-（2-酚）-5）桥接的混合价多核锰配合物的合成，晶体结构和磁性-（吡啶-2-基）-1,2,4-三唑）。配合物1至3显示类似的双核结构，其[[MnMnIII）-Mn-II（L）（2）]的中心核和其他一些小分子也与两个Mn中心配位。两个[（MnMnIII）-Mn-II（L）（2）]亚基可通过不同的二羧酸进一步连接，以构建不带电的四核配合物4至7。在这些配合物中，每个去质子化的双阴离子配体L2-均充当mu（2）-桥接的配体通过1,2,4-三唑环配位两个Mn中心。键合价和（BVS）计算和Mn周围的键长表明Mn中心在+2氧化态下与吡啶N原子配位，而另一个Mn中心在酚式O原子上处于+3氧化态。 Mn-III中心沿轴之一显示Jahn-Teller伸长率。磁性研究表明，双核（1-3）和四核（4-7）配合物中存在铁磁性Mn-III-Mn-II偶联，其偶联常数（J）为0.58至1.17 cm（-1），基于哈密顿量H = -2JS（1）.S2（S-1 = 5/2和S-2 = 2）。在所有情况下，都引入了z'J'（分子间相互作用）和D参数（Mn（III）离子的零场分裂），以改善相应的拟合度。讨论了Mn-II / Mn-III与其电子结构之间的偶联相互作用的关系。

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