One‐dimensional metal–organic frameworks built by coordinating 2,4,6‐tris(4‐pyridyl)‐1,3,5‐triazine linker with copper nodes: CO 2 adsorption properties

• Published in: Applied organometallic chemistry Vol. 37; no. 1
• Main Authors: Portolés‐Gil, Núria, Vallcorba, Oriol, Fraile‐Sainz, Julio, López‐Periago, Ana M., Domingo, Concepción, Ayllón, José A.
• Format: Journal Article
• Language: English
• Published: 01.01.2023
• ISSN: 0268-2605; 1099-0739
• DOI: 10.1002/aoc.6930

The reaction between 2,4,6‐tris(4‐pyridyl)‐1,3,5‐triazine (4‐tpt) and copper(II) hexafluoroacetylacetone (Cu(hfa) 2 ) yields two different 1D metal–organic frameworks (MOFs), [(Cu(hfa) 2 ) 2 (4‐tpt)] n ( 1 ) and [Cu(hfa) 2 (4‐tpt)] n ( 2 ). The Cu:4‐tpt ratio in the new MOFs is determined by the reaction medium, particularly, the solvent used. The two compounds have been fully characterized, including crystal structure elucidation. [(Cu(hfa) 2 ) 2 (4‐tpt)] n ( 1 ), with a 2:1 Cu:4‐tpt ratio, could be precipitated in either 1,1,2‐trichloroethane or supercritical CO 2 . In ( 1 ), 4‐tpt shows a tritopic coordination mode, but only half of the Cu(hfa) 2 subunits act as a node, thus connecting two 4‐tpt and giving a 1D network. The other half of Cu(hfa) 2 subunits are connected only to one pyridine and thus protrude along the chains. The later Cu(hfa) 2 fragments show a labile character and can be dissolved in diethyl ether to give the second MOF [Cu(hfa) 2 (4‐tpt)] n ( 2 ), with a 1:1 Cu:4‐tpt ratio. The compound ( 2 ) has also a 1D structure, with all the incorporated copper atoms acting as nodes. In this case, the packing of the chains defines accessible channels, which are perpendicular to the chain axis. After activation, N 2 adsorption/desorption measurements at 77 K confirm the microporous character of ( 2 ) with an apparent surface area of 190 m 2  g −1 . Besides, at 273 K this material clearly shows a significant adsorption of CO 2 prompted by noncoordinated nitrogen in the triazine linker.