Pham Chien Thang, Nguyen Hung Huy, Hagenbach Adelheid, Abram Ulrich
Institute of Chemistry and Biochemistry, Freie Universität Berlin , Fabeckstrasse 34-36, D-14195 Berlin, Germany.
Department of Inorganic Chemistry, VNU University of Science , 19 Le Thanh Tong, Hanoi, Vietnam.
Inorg Chem. 2017 Sep 18;56(18):11406-11416. doi: 10.1021/acs.inorgchem.7b01909. Epub 2017 Sep 5.
The reaction of isophthaloylbis(N,N-diethylthiourea), HL, with FeCl·6HO gives the dinuclear tris-complex [Fe(L)] (5), possessing a cryptand-like structure. A similar reaction with the ligand 2,6-dipicolinoylbis(N,N-diethylthiourea), HL, however, results in the formation of the anionic, mononuclear Fe(III) complex [Fe(L)] (6), which could be isolated as its "Tl salt" by the subsequent addition of Tl(NO). A tighter view to the solid state structure of the obtained product, however, characterizes compound 6 as a one-dimensional coordination polymer, in which four-coordinate Tl ions connect the {[Fe(L)]} units to infinite chains. When Fe ions and Tl ions are added to HL simultaneously in a one-pot reaction, a different product is obtained: a cationic trinuclear complex of the composition {M⊂[Fe(L)]}. It has been isolated as a PF salt and represents a {2}-metallacryptate with a nine-coordinate Tl ion in the central void. Structurally related products of the compositions {M⊂[Fe(L)]}(PF) (M = Na, K, Rb) (8(PF)) could be isolated from analogous reactions with alkaline salts instead of Tl(NO). {2}-Metallacryptates with larger central voids were synthesized with the ether-spaced aroylbis(N,N-diethylthiourea) HL. The compounds {M⊂[Fe(L)]}(PF) (M = K, Rb, Tl or Cs) (9(PF)) were prepared by a similar protocol like those with HL with the simultaneous addition of the metal ions to a solution of HL. Due to the larger spacer between the aroylthiourea units, the coordination number of the central M ions is 12 by six carbonyl and six ether oxygen atoms. All products were characterized by elemental analysis, IR spectroscopy, and X-ray structure analysis. Cyclic voltammetric studies were carried out with the three representative complexes [Fe(L)], {K⊂[Fe(L)]}(PF), and {K⊂[Fe(L)]}(PF). The obtained voltammograms indicate the dependence of the redox properties of the oligonuclear systems on the conjugation in the organic backbones of the ligands.
间苯二甲酰双（N，N - 二乙基硫脲）（HL）与FeCl₃·6H₂O反应生成具有类穴状结构的双核三配合物[Fe₂(L)₃] (5)。然而，配体2,6 - 二吡啶甲酰双（N，N - 二乙基硫脲）（HL'）发生类似反应则生成阴离子单核Fe(III)配合物[Fe(L')₂] (6)，后续加入Tl(NO₃)可将其分离为“Tl盐”。不过，对所得产物固态结构的进一步观察表明，化合物6是一种一维配位聚合物，其中四配位的Tl离子将{[Fe(L')₂]}单元连接成无限长链。当在一锅反应中同时向HL中加入Fe离子和Tl离子时，会得到不同的产物：组成为{M⊂[Fe(L')₂]}的阳离子三核配合物。它已被分离为PF₆盐，代表一种在中心空位含有九配位Tl离子的{2}-金属穴合物。通过与碱性盐而非Tl(NO₃)进行类似反应，可分离出结构相关的组成为{M⊂[Fe(L')₂]}(PF₆)（M = Na、K、Rb）(8(PF₆))的产物。用醚间隔的芳酰基双（N，N - 二乙基硫脲）HL²合成了具有更大中心空位的{2}-金属穴合物。化合物{M⊂[Fe(L²)₂]}(PF₆)（M = K、Rb、Tl或Cs）(9(PF₆))是通过与HL类似的方法制备的，即将金属离子同时加入到HL²溶液中。由于芳酰基硫脲单元之间的间隔更大，中心M离子的配位数为12，由六个羰基氧原子和六个醚氧原子配位。所有产物均通过元素分析、红外光谱和X射线结构分析进行了表征。对三种代表性配合物[Fe(L')₂]、{K⊂[Fe(L')₂]}(PF₆)和{K⊂[Fe(L²)₂]}(PF₆)进行了循环伏安研究。所得伏安图表明寡核体系的氧化还原性质取决于配体有机主链中的共轭作用。
