刚性配体经自发拆分构筑的dia型螺旋对映框架

Enantiomeric Helical Frameworks with dia Net Based on Rigid Ligands from Spontaneous Resolution

刚性的2⁃甲氧基对苯二甲酸(H2MPA)和2,5⁃二(1H⁃咪唑⁃1⁃基)吡啶(2,5⁃DIP)与Zn^(2+)通过自发拆分得到了一对组成为[Zn(MPA)(2,5⁃DIP)]·1.4H2O的对映体1Δ和1Λ。结构分析揭示1Δ和1Λ分别结晶于手性空间群P4_(1)和P4_(3),Flack参数都接近于0。在1Δ和1Λ中,Zn^(2+)与配体MPA2-和/或2,5⁃DIP沿着c轴方向形成了3对对映的螺旋链。尽管3种螺旋链的组成和结构不同,但1Δ中的螺旋链都表现为右手构型,而1Λ中的螺旋链则呈对映的左手构型。此外,由3种螺旋链构建的孔道宽度分别达到了1.1 nm×1.1 nm、1.1 nm×0.8 nm和0.8 nm×0.8 nm,如此空旷的结构导致整个框架是五重穿插特征的dia型网络。此外,配合物1在紫外可见光谱的紫外区有强的吸收,而固体荧光测试表明其有蓝色荧光特征,强的荧光发射峰在435 nm处。

The enantiomers of complex 1(1Δand 1Λ),[Zn(MPA)(2,5⁃DIP)]·1.4H2O(H2MPA=2⁃methoxyterephthalic acid,2,5⁃DIP=2,5⁃di(1H⁃imidazol⁃1⁃yl)pyridine)were obtained by spontaneous resolution upon crystallization in the absence of any enantiopure reagents under hydrothermal condition.X⁃ray crystallography reveals that complexes 1Δand 1Λcrystallize in chiral space groups P4_(1) and P4_(3) with near⁃zero Flack parameters,respectively.In complexes 1Δand 1Λ,three types of helical chains are constructed by Zn^(2+) ions,MPA2-and/or 2,5⁃DIP ligands along c axis.Although these helical chains contain different components and show different structures,they still have same righthanded helical configuration in 1Δand left⁃handed helical configuration in 1Λ,respectively.For the width of channels based on helical chains are up to 1.1 nm×1.1 nm,1.1 nm×0.8 nm and 0.8 nm×0.8 nm,respectively,and such empty structures result in 5⁃fold⁃interpenetrating 3D frameworks with 4⁃connected dia net in complexes 1Δand 1Λ.Furthermore,UV⁃Vis spectra measurement for 1 showed a strong absorption band in ultraviolet region,while solid fluorescence curve revealed blue fluorescence property with emission peak at about 435 nm in complex 1.CCDC:2049948,1Δ;2049947,1Λ.