[M(Me6Tren)X]X complex as efficacious bifunctional catalyst for CO2 cycloaddition: The synergism of the metal and halogen ions

Authors：Wei, Fen; Tang, Jia; Zuhra, Zareen; Wang, Shoushan; Wang, Xiaoxia; Wang, Xiufang^*; Xie, Guanqun

Source：Journal of CO2 Utilization, 2022, 61: 102048.

DOI：10.1016/j.jcou.2022.102048

• Homogeneous catalysis
• Carbon dioxide fixation
• Green chemistry
• Structure-activity relationships
• Acid-base catalysis

Efficient catalysis for fixation and conversion of CO2 is of significance to carbon neutralization. Here, a series of C-3 symmetric bifunctional complex catalysts with different metals (Ni, Co, Cu) have been strategically synthesized and evaluated in the CO2 cycloaddition with epoxides. Among these catalysts, [Ni(Me6Tren)I]I 3c exhibits the best performance affording up to 99.1% yield of chloropropylene carbonate under ambient (60 C, CO2 balloon), cocatalyst-and solvent-free conditions. TPD and XPS showed 3c possessed excellent acid center. Single crystal X-ray diffraction indicated the facile dissociation of Ni-I based on the bond length information. The synergistic effect of the Ni(II) acidic center, the axial and outer iodine ions was discussed. Based on the structure activity relationship, plausible reaction pathways were proposed for the bifunctional catalysts. Moreover, a largescale synthesis of chloropropylene carbonate (350 mmol) and recyclability of 3c catalyst highlight its potential for industrial applications.

• Institution
  东莞理工学院; 广东药学院