School of Chemistry and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Melbourne, Victoria, 3010, Australia.
Dalton Trans. 2010 Mar 21;39(11):2831-7. doi: 10.1039/b922127a. Epub 2010 Feb 5.
A new 1,3-diaminopropane bridged bis(thiosemicarbazone) ligand (H(4)L) has been synthesised. The new hexadentate ligand is capable of forming six coordinate complexes with rhenium(V), iron(III) and cobalt(III). In the case of the iron(III) and cobalt(III) complexes the ligand doubly deprotonates to give the monocations Fe(III)(H(2)L) and Co(III)(H(2)L) in which the metal ion is in a distorted octahedral environment. In the rhenium(V) complex the ligand loses four protons by deprotonation of both secondary amine nitrogen atoms to give Re(V)(L) with the metal ion in a distorted trigonal prismatic coordination environment. Re(V)(L) represents a rare example of a rhenium(V) complex that does not contain one of the ReO(3+), ReN(2+) or Re(NPh)(2+) cores. The new ligand and metal complexes have been characterised by a combination of NMR spectroscopy, X-ray crystallography, mass spectrometry and microanalysis. The electrochemistry of Fe(III)(H(2)L), Co(III)(H(2)L) and Re(V)(L) has been investigated by cyclic voltammetry with each complex undergoing a single electron reduction event. It is possible to prepare the rhenium(V) complex from ReOCl(3)(PPh(3))(2) or directly from ReO(4) with the addition of a reductant, which suggests the new ligand may be of interest in the development of rhenium radiopharmaceuticals.
一种新的 1,3-二氨基丙烷桥联双（硫代缩氨基脲）配体（H(4)L）已经被合成。这种新的六配位配体能够与铼（V）、铁（III）和钴（III）形成六配位配合物。在铁（III）和钴（III）配合物的情况下，配体发生双重去质子化，生成单核阳离子Fe(III)(H(2)L)和Co(III)(H(2)L)，其中金属离子处于扭曲的八面体环境中。在铼（V）配合物中，配体通过两个仲氨基氮原子的去质子化失去四个质子，生成具有扭曲三角棱柱配位环境的Re(V)(L)，其中金属离子处于扭曲三角棱柱配位环境中。Re(V)(L)代表了一个罕见的例子，即不包含 ReO(3+)、ReN(2+)或 Re(NPh)(2+)核的铼（V）配合物。新的配体和金属配合物通过 NMR 光谱、X 射线晶体学、质谱和微量分析进行了表征。通过循环伏安法研究了Fe(III)(H(2)L)、Co(III)(H(2)L)和Re(V)(L)的电化学性质，每个配合物都经历了一次单电子还原事件。可以从 ReOCl(3)(PPh(3))(2)或直接从ReO(4)制备铼（V）配合物，加入还原剂，这表明新的配体可能对开发铼放射性药物感兴趣。
