Catalytic CO2 Fixation over a Robust Lactam-Functionalized Cu(II) Metal Organic Framework

• Published in: Inorganic chemistry 2019-08, Vol.58 (15), p.9723-9732
• Main Authors: Ansari, Shagufi Naz, Kumar, Pawan, Gupta, Anoop K, Mathur, Pradeep, Mobin, Shaikh M
• Format: Article
• Language: English
• ISSN: 0020-1669; 1520-510X
• DOI: 10.1021/acs.inorgchem.9b00684

A porous, Cu­(II)-metal organic framework (Cu-MOF) constituted of a rigid lactam functionalized ditopic ligand (H2L) was synthesized at room temperature under slow evaporation conditions {H2L = (5-(1-oxo-2,3-dihydro-1H-inden-2-yl)­isophthalic acid)}. The single crystal X-ray structure revealed the formation of a 3D framework of Cu-MOF with one-dimensional (1D) channels decorated with lactam groups and exposed metal centers in the crystallographic c-axis. Interestingly, Cu­(II) coordinated DMF molecules were eliminated from the Cu­(II) metal center on activation of Cu-MOF at a temperature of 150 °C under high vacuum to generate a solvent free framework with pores lined with unsaturated Lewis acidic Cu­(II) ions, i.e., Cu-MOF′. The lactam functionalized channels inclined toward the CO2, which interact with the Cu­(II) metal sites lined in the channels of Cu-MOF′ and exhibit fascinating solvent-free heterogeneous catalytic conversion of CO2 to cyclic carbonates at atmospheric pressure of CO2, under mild conditions. Furthermore, the Cu-MOF′ catalyst was easily recycled and reused for several cycles without a significant loss in catalytic activity.