Modulating the regioselectivity of solid-state photodimerization in coordination polymer crystals.
Modulating the regioselectivity of solid-state photodimerization in coordination polymer crystals.
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DOI：
10.1039/d0dt02038a
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发表时间：
2020-07
影响因子：
4
通讯作者：
Feilong Hu;Zhen Qin;Meng-Fan Wang;Xue Wan Kang;Yong-Li Qin;Yong Wang;Shu-Li Chen;D. Young
中科院分区：
文献类型：
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作者：
Feilong Hu;Zhen Qin;Meng-Fan Wang;Xue Wan Kang;Yong-Li Qin;Yong Wang;Shu-Li Chen;D. Young
在溶剂热条件下合成了配位聚合物[Cd(1，4-bpeb)2(L2)2(SO42-)2](2)，[Cd(1，4-bpeb)2(L2)2(SO42-)2](2)和[Cd(1，4-bpeb)(L3)](H2O)(3)(HL1，3-[2-(3-hydroxy-phenoxymethyl)-benzyloxy]-benzoic酸；HL2，1H-吲唑-3-羧酸；H3L3，苯-1，2，3-三元酸；1，4-bpeb，1，4-双[2-(4-吡啶)乙烯基]苯)苯。化合物1-3在固态条件下进行光二聚反应，得到单异构体的定量产率。羧基配体L和金属中心的选择决定了1，4-BPEB配体的排列，而1，4-BPEB配体的排列又指导了最终光产物的区域化学。Cd基化合物1和3的固态网络结构中，1，4-bpeb对以C[双键，长度为m-短划线]C中心以适当的距离面对面排列，并以光二聚方式排列得到相应的对-[2.2]环烷(PCP)。相反，化合物2具有双核(ZnSO4)2金属环，使1，4-bpeb“臂”面对面定位，但C[双键，长度为m-短划线]C中心偏移在适当距离，只有一对可以进行[2+2]环加成反应，生成单环丁烷光产物bpbpvpcb的单一立体异构体。这项工作突出了晶体工程设计原则，可以用来促进固态转换中的区域和立体专一性。
Coordination polymers [Cd(1,4-bpeb)(L1)] (1), [Zn2(1,4-bpeb)2(L2)2(SO42-)2] (2) and [Cd(1,4-bpeb)(L3)] (H2O) (3) (H2L1, 3-[2-(3-hydroxy-phenoxymethyl)-benzyloxy]-benzoic acid; HL2, 1H-Indazole-3-carboxylic acid; H3L3, benzene-1,2,3-tricarboxylic acid; 1,4-bpeb, 1,4-bis[2-(4-pyridyl)vinyl]benzene have been synthesized under solvothermal conditions. Complexes 1-3 underwent photodimerization in the solid-state to give quantitative yields of single isomeric products. The choice of carboxyl ligands L and metal center determined the arrangement of 1,4-bpeb ligands, which in turn directed the regiochemistry of the final photoproducts. The solid-state network structures of cadmium based 1 and 3 had 1,4-bpeb pairs aligned face-to-face with both C[double bond, length as m-dash]C centres in each ligand at an appropriate distance and alignment for photodimerization to give the corresponding para-[2.2]cyclophane (pCP) exclusively. By contrast, compound 2 possessed dinuclear (ZnSO4)2 metallocycles that positioned the 1,4-bpeb "arms" face-to-face, but with C[double bond, length as m-dash]C centres offset at an appropriate distance for only one pair to undergo [2 + 2] cycloaddition to yield a single stereoisomer of the monocyclobutane photo-product bpbpvpcb. This work highlights crystal engineering design principles that can be used to facilitate regio- and stereospecificity in solid-state transformations.