Click-Triazole N2 Coordination to Transition-Metal Ions Is Assisted by a Pendant Pyridine Substituent
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- 作者：Damijana Urankar ; Balazs Pinter ; Andrej Pevec ; Frank De Proft ; Iztok Turel ; Janez Komrlj
- 刊名：Inorganic Chemistry
- 出版年：2010
- 出版时间：June 7, 2010
- 年：2010
- 卷：49
- 期：11
- 页码：4820-4829
- 全文大小：1035K
- 年卷期：v.49,no.11(June 7, 2010)
- ISSN：1520-510X
文摘
We report that 1-(2-picolyl)-1,2,3-triazole (click triazole) forms stable complexes with transition-metal ions in which the coordination involves the triazole N2 nitrogen atom and the pendant 2-picolyl group. This is exemplified by model compound 1-(2-picolyl)-4-phenyl-1H-1,2,3-triazole (Lx) and its complexes with transition-metal ions of PtII, PdII, CuII, RuII, and AgI. The coordination was investigated experimentally and theoretically. Ligand Lx easily reacted at room temperature with cis-[PtCl2(DMSO)2], [Pd(CH3CN)4](BF4)2, CuCl2, [RuCl(μ-Cl)(η6-p-cymene)]2, and AgNO3 to give stable chelates [PtCl2Lx] (1), [Pd(Lx)2](BF4)2 (2), [CuCl2(Lx)2] (3), [RuCl(η6-p-cymene)Lx]OTf (4), and [Ag2(Lx)2(NO3)2] (5), respectively, in 60−98% yield. The structures of 1−5 were unambiguously confirmed by NMR spectroscopy and single-crystal X-ray diffraction analysis. Density functional theory calculations were carried out in order to theoretically investigate the stabilization factors in 1−5. A comparison of the chelating properties of ligand Lx was made with structurally similar and isomeric 1-(2-aminoethyl)-substituted 1,2,3-triazole (Ly) and 4-(2-aminoethyl)-substituted 1,2,3-triazole (Lz). The complexation affinity of Lx was attributed to π-back-donation from the metal to the pendant pyridine side arm, whereas the stability of the complexes involving Ly and Lz mainly originates from efficient π-back-donation to the triazole ring.