Versatile Coordinative Abilities of a New Hybrid Pteridine-Thiosemicarbazone Ligand: Crystal Structure, Spectroscopic Characterization, and Luminescent Properties
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- 作者：Sonia B. Jimé ; nez-Pulido ; Fá ; tima M. Linares-Ordó ; ñ ; ez ; Miguel N. Moreno-Carretero ; Miguel Quiró ; s-Olozá ; bal
- 刊名：Inorganic Chemistry
- 出版年：2008
- 出版时间：February 4, 2008
- 年：2008
- 卷：47
- 期：3
- 页码：1096 - 1106
- 全文大小：218K
- 年卷期：v.47,no.3(February 4, 2008)
- ISSN：1520-510X
文摘
The synthesis and characterization of the first thiosemicarbazone-lumazine (TSCLMH = the thiosemicarbazone of6-acetyl-1,3,7-trimethyllumazine) hybrid ligand is reported. The influence of the conformation of this compound onits energy and the atomic contribution to the molecular orbitals have been theoretically investigated. Ni(II), Cu(I),Zn(II), and Cd(II) complexes of this ligand have been synthesized and characterized by elemental analysis,thermogravimetric studies, IR, 1H, 13C, and 15N NMR, and UV-vis-NIR spectroscopy, magnetic measurements,and X-ray crystallography. Four types of coordination modes for the ligand may be predicted: (a) double bidentate;(b) tetradentate; (c) tridentate; (d) bidentate. Structures of representative complexes of types a, b, and d havebeen determined by X-ray crystallography. In the [Cu(TSCLMH)]2(ClO4)2 complex, TSCLMH acts as a doubly bidentatebridging ligand forming a dimer with a Cu···Cu distance of 2.876 Å. The geometry around the metal ion is trigonallydistorted tetrahedral with a relatively long (four-atom) bridge between the metal centers instead of the shorter,mainly single atom, bridges present in other thiosemicarbazone derivatives complexes. In the [Cd(NO3)2(TSCLMH)(EtOH)] complex, the metal ion displays eight-coordinated geometry with the TSCLMH ligand acting in a tetradentateplanar fashion and two nitrate anions, one monodentate and the other bidentate. The coordination polyhedron in[Cd(TSCLM)2(H2O)]·MeOH·2H2O is a square pyramid with two monoanionic ligands acting as bidentate NS donorsand a water molecule completing the coordination sphere. Fluorescence spectroscopic properties of TSCLMHhave been studied as well as the changes in position and intensity of fluorescence bands caused by the complexationwith different metal ions (Ni2+, Cu+, Zn2+, Cd2+).