A PCP Pincer Ligand for Coordination Polymers with Versatile Chemical Reactivity: Selective Activation of CO2 Gas over CO Gas in the Solid State

• Published in: Angewandte Chemie International Edition 2016-09, Vol.55 (40), p.12351-12355
• Main Authors: He, Junpeng, Waggoner, Nolan W., Dunning, Samuel G., Steiner, Alexander, Lynch, Vincent M., Humphrey, Simon M.
• Format: Article
• Language: English
• Subjects: Adsorption; Carbon dioxide; Carbon monoxide; Chemical reactions; Chemical synthesis; CO2 activation; Coordination polymers; Crystal structure; Diffraction; Insertion; Ligands; Metal-organic frameworks; Palladium; PCP pincer ligands; Polymers; selective adsorption; Solid state; X-ray diffraction
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.201604730

A tetra(carboxylated) PCP pincer ligand has been synthesized as a building block for porous coordination polymers (PCPs). The air‐ and moisture‐stable PCP metalloligands are rigid tetratopic linkers that are geometrically akin to ligands used in the synthesis of robust metal–organic frameworks (MOFs). Here, the design principle is demonstrated by cyclometalation with PdIICl and subsequent use of the metalloligand to prepare a crystalline 3D MOF by direct reaction with CoII ions and structural resolution by single crystal X‐ray diffraction. The Pd−Cl groups inside the pores are accessible to post‐synthetic modifications that facilitate chemical reactions previously unobserved in MOFs: a Pd−CH3 activated material undergoes rapid insertion of CO2 gas to give Pd−OC(O)CH3 at 1 atm and 298 K. However, since the material is highly selective for the adsorption of CO2 over CO, a Pd−N3 modified version resists CO insertion under the same conditions. Poly‐PCP‐pincers: A new synthetic strategy for the formation of crystalline, porous versions of PCP‐pincer complexes is presented. These complexes can selectively activate gas molecules, such as CO2 over CO, in the solid state. PCP=Porous Coordination Polymer