Self-assembly of [Cu<sub>3</sub>I<sub>2</sub>]- or [CuI]<sub>n</sub>-based (n = 2, 4, and ∞) coordination polymers from unsymmetrical bis(pyridyl) and in situ ligands: syntheses, structures, and properties
作者:Zhu-Yan Zhang、Zhao-Peng Deng、Xian-Fa Zhang、Li-Hua Huo、Hui Zhao、Shan Gao
DOI:10.1039/c3ce41774c
日期:——
Five new copper coordination polymers, [CuI(L1a)]n (1), [Cu1.5I(dmtrz)0.5(PPh3)]n·0.5n(CH3CN) (2), [Cu2I2(L1b)]n (3), [Cu4I4(L2)]n·nH2O (4), and [CuI(L3)]n (5) (L1a = N-(pyridin-2-ylmethyl)-N-(pyridin-3-yl)formamide, Hdmtrz = 3,5-dimethyl-4H-1,2,4-triazole, L1b = N-(pyridin-2-ylmethylene)pyridin-3-amine, L2 = N-(pyridin-4-ylmethyl)pyridin-3-amine, L3 = N-(pyridin-3-ylmethyl)pyridin-2-amine), have been synthesized by the solvothermal reactions of CuI and three unsymmetrical bis(pyridyl) ligands in mixed methanolâacetonitrile solution and characterized using elemental analysis, IR, TG, PL, XPS, powder and single-crystal X-ray diffraction. In 1, the ligand L1a is in situ generated from N-(pyridin-2-ylmethyl)pyridin-3-amine (L1) and bridges adjacent Cu2I2 rhomboid units, forming a double chain structure. The rare Cu3I2 clusters in 2 are linked by the dmtrzâ monoanion to generate a linear chain structure, in which the dmtrzâ monoanion is in situ synthesized by a non-ammonia pathway. The L1b in 3 is also in situ generated from L1 and connects adjacent chair like Cu4I4 clusters into a (4,4) layer structure. By contrast, the Cu4I4 cubanes in 4 are linked by the L2 ligands to form a 2-fold interpenetration (44·62) net. The Cu(I) cations in 5 are linked by the μ3-Iâ ions into infinite double-stranded [Cu2I2]n ladder chains, which are further extended into a layer structure by the L3 molecules. Moreover, the binding energies of the Cu 2p3/2 level in the XPS spectra are typical for a Cu(I) oxidation state. For the N1s, the different binding energies in the XPS spectra can be attributed to the N atoms with different chemical environments. Luminescent property investigation shows that only 5 exhibits a blue emission maximum at 475 nm.
五种新型铜配位聚合物,[CuI(L1a)]n (1)、[Cu1.5I(dmtrz)0.5(PPh3)]n·0.5n(CH3CN) (2)、[Cu2I2(L1b)]n (3) ,[Cu4I4(L2)]n·nH2O (4) 和 [CuI(L3)]n (5) (L1a = N-(吡啶-2-基甲基)-N-(吡啶-3-基)甲酰胺,Hdmtrz = 3,5-二甲基-4H-1,2,4-三唑,L1b = N-(吡啶-2-基亚甲基)吡啶-3-胺,L2 = N-(吡啶-4-基甲基)吡啶-3-胺,L3 = N-(吡啶-3-基甲基)吡啶-2-胺),通过 CuI 和三个不对称双(吡啶基)配体在混合甲醇-乙腈溶液中的溶剂热反应合成,并使用元素分析、红外表征、TG、PL、XPS、粉末和单晶X射线衍射。在图1中,配体L1a由N-(吡啶-2-基甲基)吡啶-3-胺(L1)原位生成,并桥接相邻的Cu2I2菱形单元,形成双链结构。 2中稀有的Cu3I2簇通过dmtrz-单阴离子连接生成线性链结构,其中dmtrz-单阴离子是通过非氨途径原位合成的。 3中的L1b也是由L1原位生成的,并将相邻的椅子状Cu4I4簇连接成(4,4)层结构。相比之下,4中的Cu4I4立方烷通过L2配体连接形成2倍互穿(44×62)网。 5中的Cu(I)阳离子通过μ3-I-离子连接成无限双链[Cu2I2]n梯链,并通过L3分子进一步延伸成层结构。此外,XPS 光谱中 Cu 2p3/2 能级的结合能是 Cu(I) 氧化态的典型结合能。对于N1s,XPS光谱中不同的结合能可归因于具有不同化学环境的N原子。发光特性研究表明,只有 5 个在 475 nm 处表现出蓝色发射最大值。