Solar-driven straightforward one-step synthesis of pyridine derivatives in the absence of photosensitizer is of considerable interest but greatly challenging in synthetic and medicinal chemistry. Herein, an unprecedented 2-fold interpenetrated lvt polyoxometalate-based open framework (POM-OF), LCU-22 ([Zn(1-ipIM) 3 ] 2 [Zn 6 (AsW 9 O 33 ) 2 (1-ipIM) 6 ]·2(1-HipIM), 1-ipIM = 1-isopropyl imidazole) has been synthesized in gram-scale quantities using one-pot reaction and structurally characterized by X-ray crystallography. The cluster node in LCU-22 is a Zn 6 ring seamed trivacant polyoxotungstate cluster ([Zn 6 (AsW 9 O 33 ) 2 ]), which is quadruply extended by [Zn(1-ipIM) 3 ] 2+ units to form the final 3D open framework. Remarkably, LCU-22 is highly stable over wide pH range and in various solvents, and dramatically boosted the white light-powered heterogeneous photocatalysis for synthesis of pyridine derivatives in good yields after three times recycles utilization. This work not only builds a novel POM-OF but also underscores the unique advantages of transition metal cluster substituted polyoxotungstates frameworks used for selective photocatalytic formation of value-added organic molecules.
Xianqiang Huang,Yuquan Qi,Yuxiao Gu,Shuwen Gong,Guodong Shen,Qiang Li,Jikun Li
A synthetic pathway for the directed preparation of three novel polyoxovanadate-based copper frameworks (POVCFs), i.e., [Cu0.5(1-ipIM)2]2[V4O11] (POVCF 1), [Cu(1-ipIM)2](VO3)2 (POVCF 2) and [Cu(1-pIM)4](HpIM)4[V10O28] (POVCF 3) (1-ipIM = 1-isopropylimidazole; 1-pIM = 1-propylimidazole) using bifunctional imidazole molecules as organic ligands and base has been developed. Systematic studies revealed that the variable base enviroment in the reaction is the key step in the preparation of 1D to 3D supermolecular networks of POVCFs 1–3. Single crystal X-ray diffraction analyses demonstrated that the Cu2+ atoms of POVCFs 1–2 were coordinated with four imidazole derivative molecules and two different polyoxovanadate {[V4O11]2− and [V10O28]6−} clusters, respectively, exhibiting a [CuN4O2] binding set and a distorted octahedral geometry. Specifically, POVCF 1 exhibited adjacent [V4O11]2− that dangle up and down arranged in a parallel 2D network and further coordinated with [Cu(1-ipIM)4]2+ to form a 3D supramolecular structure. However, POVCF 3 presented one tetrahedral coordinated vanadium atom and one four-coordinated copper atom and they further gave rise to a 1D network by the Cu–O and V–O bonds. More importantly, these POVCFs were further studied in the construction of C–N bond reactions of primary amines under mild conditions, and it was found that POVCF 1 displayed efficient heterogeneous catalytic activities in the Chan–Lam reaction (yields up to 89%).
危险品化学品经营许可证（带存储）