Cobalt-based metal coordination polymers with 4,4′-bipyridinyl groups: highly efficient catalysis for one-pot synthesis of 3,4-dihydropyrimidin-2(1H)-ones under solvent-free conditions

• Published in: Applied organometallic chemistry 2016-12, Vol.30 (12), p.1009-1021
• Main Authors: Wang, Jin-Hua, Tang, Gui-Mei, Yan, Shi-Chen, Wang, Yong-Tao, Zhan, Shi-Jie, Zhang, E, Sun, Yu, Jiang, Yuan, Cui, Yue-Zhi
• Format: Article
• Language: English
• Subjects: 3,4‐dihydropyrimidin‐2(1H)‐ones; 4-dihydropyrimidin-2(1H)-ones; Architecture; biginelli reaction; Catalysis; Catalysts; Coordination compounds; Coordination polymers; Hydrophobicity; metal coordination polymers; Solvents; Synthesis (chemistry); three-component reaction
• ISSN: 0268-2605; 1099-0739
• DOI: 10.1002/aoc.3535

Three new metal coordination complexes, namely [Co(BPY)2(H2O)2](BPY)(BS)2(H2O)4 (1), [Co(BPY)2(H2O)4](ABS)2(H2O)2 (2) and [Co(BPY)(H2O)4](MBS)2 (3) (BPY = 4,4′‐bipyridine, BS = phenylsulfonic acid, ABS = p‐aminobenzenesulfonic acid, MBS = p‐methylbenzenesulfonic acid), were obtained under hydrothermal conditions. Complexes 1, 2, 3 were structurally characterized using single‐crystal X‐ray diffraction and infrared spectroscopy. All of them display low‐dimensional motifs: complex 1 displays a two‐dimensional structure; and complexes 2 and 3 exhibit a one‐dimensional tape structure. Through strong intermolecular hydrogen bonding interactions and weak packing interactions, all of them further stack to generate a three‐dimensional supramolecular architecture. Catalysts 1, 2, 3 were involved in the green synthesis of a variety of 3,4‐dihydropyrimidin‐2(1H)‐ones under solvent‐free conditions through Biginelli reactions. The corresponding catalytic product was obtained in quantitative yields (99%) under eco‐friendly synthesis conditions for the variety of reactions. Catalysts 1, 2, 3 exhibit excellent efficiency for the desired product, and their catalytic performance shows the following order: 2 > 1 ≈ 3, which can be ascribed to the hydrophobic interactions of different phenylsulfonate groups. The catalytic performance for the Biginelli reaction is not only dependent on the selected solvents, but also inversely proportional to the polarities of the solvents. Copyright © 2016 John Wiley & Sons, Ltd. A set of cobalt‐based metal coordination polymers containing phenylsulfonate and 4,4‐bipyridine ligands were obtained under hydrothermal conditions. They show high catalytic performance for the green synthesis of a variety of 3,4‐dihydropyrimidin‐2(1H)‐ones under solvent‐free conditions through Biginelli reactions.