Chemical Fixation of CO2 and Other Heterogeneous Catalytic Studies by Employing a Layered Cu‐Porphyrin Prepared Through Single‐Crystal to Single‐Crystal Exchange of a Zn Analogue. Issue 1 (30th November 2017) - Dutta, Gargi
Abstract: A solvothermal reaction of Zn(NO3 )2 ⋅ 6 H2 O, tetra‐(4‐pyridyl)porphyrin (H2 TPyP), and 4, 4′‐oxybis(benzoic acid) (H2 OBA) resulted in a new two‐dimensional Zn‐ porphyrin metal–organic framework compound, [Zn2 (C40 H24 N8 )0.5 (C14 H8 O5 )(DMA)](DMA)(H2 O)6 (1 ; DMA= N, N ‐dimethylacetamide). The Zn II ions present in1 could be exchanged by using a solution of Cu(NO3 )2 ⋅ 3 H2 O in DMA at room temperature to give [Cu2 (C40 H24 N8 )0.5 (C14 H8 O5 )(DMA)](DMA)(H2 O)3 (Cu ∈ 1 ). The extra‐framework solvent molecules have been shown to be reversibly removed or exchanged without collapse of the framework. Solvent‐freeCu ∈ 1 was explored as an active heterogeneous catalyst towards three different organic reactions: 1) the chemical fixation of CO2 into cyclic carbonate at room temperature and 1 atm; 2) the nitroaldol reaction under solvent‐free conditions, and 3) the three‐component coupling of aminopyridine, benzaldehyde, and aryl alkynes followed by 5‐ exo ‐dig cyclization to produce the important pharmacophore imidazopyridine. Abstract : Exchange studies : The synthesis, structure, and Cu‐exchange (single‐crystal‐to‐single‐crystal fashion) of a porphyrin‐based metal–organic framework is described. The copper‐exchanged compound exhibits catalytic activity towards the chemical fixation of CO2 under ambient conditions, the nitroaldol reaction, and the three‐component coupling reaction (see figure).