Diacetoneglucose Complexes of Manganese(II) and Iron(II) and Their Organometallic Derivatization

Homoleptic metal−sugar complexes were obtained in the form of MnII− and FeII−diacetoneglucose derivatives.
The protolysis of [Mn3Mes6] and [Fe2Mes4] (Mes = 2,4,6-Me3C6H2) with DAGH (1,2:5,6-di-O-isopropylidene-α-d-glucofuranose, diacetoneglucose) led to [M(DAG)2] [M = Mn (1), Fe (2)]. Although monomeric in solution,
they showed a different degree of aggregation in the solid state, iron being monomeric and manganese oligomeric
(see magnetic properties). Dimeric complexes from 1 and 2 were obtained in the reaction with 9,10-phenanthroline
[phen], leading to [(phen)2M(μ-DAG)2M(DAG)2] [M = Mn (3), Fe (4)]. The organometallic functionalization
of 1 and 2 was achieved via a ligand redistribution reaction mixing them with [Mn3Mes6] and [Fe2Mes4],
respectively. The reaction led to mixed alkoxo aryl trinuclear complexes in the form of [(Mes)2M2(μ-DAG)2M(μ-Mes)2] [M = Mn (5), Fe (6)]. Both have a linear trimetallic skeleton with Mn···Mn and Fe···Fe average
distances of 2.93 and 2.88 Å, respectively. The crystal data are as follows:  complex 5, C60H82Mn3O12, monoclinic,
space group P21, a = 10.289(5) Å, b = 20.878(5) Å, c = 14.015(5) Å, β = 93.19(2)°, Z = 2; complex 6,
C60H82Fe3O12, monoclinic, space group P21, a = 9.748(12) Å, b = 26.05(3) Å, c = 12.50(2) Å, β = 107.50(2)°,
Z = 2. The data were collected at −123 °C. For 5 and 6 the magnetic analysis showed a strong antiferromagnetic
coupling between the M(II) centers, with spin frustration leading to an overall S = 5/2 and S = 2 ground state,
respectively.

本研究成功制备了同配金属-糖配合物，其具体形式为二价锰（Mn(II)）与二价铁（Fe(II)）的双丙酮葡萄糖（diacetoneglucose）衍生物。
以[Mn3Mes6]与[Fe2Mes4]（Mes为2,4,6-三甲基苯基，即均三甲苯基）与DAGH进行质子解反应，其中DAGH为1,2:5,6-二-O-异亚丙基-α-D-呋喃葡萄糖，又称双丙酮葡萄糖，最终得到了[M(DAG)2]配合物，其中M分别为Mn（配合物1）、Fe（配合物2）。尽管两种配合物在溶液中均呈单核单分子态，但在固态下的聚集程度存在显著差异：铁配合物仍保持单核结构，而锰配合物则发生寡聚，相关磁学性质详见表征部分。
将配合物1与2分别与9,10-邻菲啰啉（phenanthroline，缩写phen）反应，可得到双核配合物，产物结构为[(phen)2M(μ-DAG)2M(DAG)2]，其中M分别为Mn（配合物3）、Fe（配合物4）。
通过配体重分配反应，分别将配合物1与[Mn3Mes6]混合、配合物2与[Fe2Mes4]混合，即可实现二者的有机金属功能化；该反应得到了混合烷氧基芳基三核金属配合物，其结构通式为[(Mes)2M2(μ-DAG)2M(μ-Mes)2]，其中M分别为Mn（配合物5）、Fe（配合物6）。
两种配合物均具有线性三金属骨架，Mn···Mn与Fe···Fe的平均间距分别为2.93 Å与2.88 Å。
两种配合物的晶体学数据如下：配合物5：分子式C60H82Mn3O12，单斜晶系，空间群P21，晶胞参数a=10.289(5) Å，b=20.878(5) Å，c=14.015(5) Å，β=93.19(2)°，Z=2；配合物6：分子式C60H82Fe3O12，单斜晶系，空间群P21，晶胞参数a=9.748(12) Å，b=26.05(3) Å，c=12.50(2) Å，β=107.50(2)°，Z=2。
晶体数据采集于-123 ℃。
对配合物5与6的磁学分析表明，其二价金属中心之间存在强反铁磁耦合作用；由于自旋阻挫效应，二者的基态总自旋分别为S=5/2与S=2。