A novel class of oligomeric and polymeric d10 metal complexes of asymmetrical N-heterocyclic ligand with strong π-stacking and hydrogen bonding: syntheses, structures, and photoluminescence
作者:Wang Jing-lin、Liu Bin、Yang Bin-sheng
DOI:10.1039/c1ce05890h
日期:——
A novel asymmetric N-heterocyclic ligand, 1·H2O [1 = (E)-1-methyl-4-nitro-Nâ²-(pyridin-2-ylmethylene)-1H-pyrrole-2-carbohydrazide], was generated by a facile route, and some closed shell metal complexes of the ligand were also synthesized. These complexes include [Zn(1)Cl2] (2), [Cd(1)(μ-Cl)2]n (3), [Hg(1)Cl2] (4) and [K(μ-1)(μ-NO3)]n (5), which were characterized by X-ray crystallography, IR and 1H-NMR spectroscopy, and elemental analyses. The structural studies indicate that ligand 1, with its different conformations and new coordination modes, is an important building block for designing and constructing supramolecular structures via Ïâ¯Ï stacking, hydrogen bonding, Clâ¯Cl and d10âd10 interactions. These interactions not only reinforce the stability of structures, but also correlate with the physical properties of complexes. The UV and fluorescence spectral properties were investigated in solution. The titration experiments by d10 metal ions imply that ligand 1 forms stable complexes at a 1â:â1 ratio and exhibits enhanced fluorescence. Moreover, compared with the solution fluorescence spectra, the solid-state spectra show more significant red-shifts, suggesting that complexes 2â4 have possible applications as light emission materials.
一种新型非对称N-杂环配体1·H2O [(E)-1-甲基-4-硝基-N'-(吡啶-2-亚甲基)-1H-吡咯-2-甲酰肼]通过简易方法合成,并合成了一系列闭壳层金属配合物。这些配合物包括[Zn(1)Cl2](2)、[Cd(1)(μ-Cl)2]n(3)、[Hg(1)Cl2](4)和[K(μ-1)(μ-NO3)]n(5),并通过X射线晶体学、红外和核磁共振光谱以及元素分析进行了表征。结构研究表明,由于配体1具有不同的构象和新的配位模式,成为通过π…π堆积、氢键、Cl…Cl和d10-d10相互作用来设计构建超分子结构的重要构建块。这些相互作用不仅增强了结构的稳定性,而且与配合物的物理性质相关。此外,在溶液中研究了UV和荧光光谱性质。通过d10金属离子的滴定实验表明,配体1与金属离子以1:1比例形成稳定配合物并表现出增强的荧光。此外,与溶液荧光光谱相比,固态光谱显示出更显著的红移,表明配合物2-4有可能作为发光材料应用。