Dinuclear di(µ-alkoxo) bridged [Fe2L12] 1 (L1 = trianion of 1,3-bis(salicylideneamino)propan-2-ol) and [Fe2L22] 2 (L2 = trianion of 1,3-bis(salicylamino)propan-2-ol) and di(µ-phenoxo) bridged [Fe2L32] 3 (L3 = trianion of 4-methyl-2,6-bis(salicylideneaminomethyl)phenol) and [Fe2L42] 4 (L4 = trianion of 4-methyl-2,6-bis(salicylaminomethyl)phenol) complexes have been synthesized and characterized. The crystal structure of 1 contains two molecules in the asymmetric unit and each molecule has two FeN2O4 distorted octahedral co-ordination units. The structure of 2 consists of a centrosymmetric dimer where the two crystallographically equivalent metal ions are asymmetrically bridged by two alkoxo oxygen atoms. The iron(III) centers have N2O4 co-ordination cores with amine nitrogens and phenolate oxygens in cis position. The crystal structure of 3 contains trans-FeN2O4 distorted octahedral co-ordination units bridged by two phenoxo oxygen atoms. The electronic spectra of all the complexes are characterized by high intensity charge-transfer transitions. Cyclic voltammetric studies of 1, 3 and 4 in dichloromethane solvent reveal stepwise reduction of FeIIIFeIII to mixed-valence FeIIIFeII and reduced FeIIFeII species while 2 exhibits a single quasireversible reduction peak corresponding to the mixed-valence form.
双核二(μ-烷氧基)桥联 [Fe2L12] 1 (L1 = 1,3-双(
水杨
氨基)丙-2-醇的三价阴离子) 和 [Fe2
L22] 2 (
L2 = 1,3-双(
水杨
氨基)
丙烷的三价阴离子-2-ol) 和二(μ-苯氧) 桥联 [Fe2L32] 3 (L3 = 4-甲基-2,6-双(
水杨基
氨基甲基)
苯酚的三价阴离子) 和 [Fe2L42] 4 (L4 = 4-甲基-三价阴离子) 2,6-双(
水杨
氨基甲基)
苯酚)配合物已被合成并表征。 1的晶体结构含有两个不对称单元分子,每个分子有两个
FeN2O4扭曲八面体配位单元。 2的结构由中心对称二聚体组成,其中两个晶体学上等价的
金属离子由两个烷氧基氧原子不对称桥接。
铁(III) 中心具有
N2O4 配位核心,胺氮和
酚氧位于顺式位置。 3的晶体结构包含由两个苯氧基氧原子桥接的反式 扭曲八面体配位单元。所有配合物的电子光谱均以高强度电荷转移跃迁为特征。在
二氯甲烷溶剂中对 1、3 和 4 进行循环伏安研究表明,FeIIIFeIII 逐步还原为混合价 FeIIIFeII 和还原型 FeIIFeII 物质,而 2 表现出与混合价形式相对应的单个准可逆还原峰。