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Updated: Dec 20, 2025
Surface Functionalization of Metal-Organic Frameworks for Improved Moisture Resistance
Published on: September 5, 2018
Solvent induced supramolecular polymorphism in Cu(II) coordination complex built from
Karim Chkirate1, Saad Fettach2, Mohamed El Hafi1
1LCOH, Département de Chimie, Faculté des Sciences, Université Mohamed V, BP1014, Rabat 10100, Morocco.
Abstract:
Two Cu(II) coordination complexes, C1 and C2 of the formula [Cu(4)2(H2O)2], have been prepared by reaction between CuCl2·2H2O and 7-ethoxycarbonylmethyl-5-methyl-1,2,4[1,5-a]pyrimidine (L) in a 1:2 M:L molar ratio. The L molecule decomposes during the reaction process into 7-carboxy-5-methyl-[1,2,4]-triazolo[1,5-a]pyrimidine (4) through an intermediate, ethyl 2,2-dihydroxy-2-(5-methyl-[1,2,4]triazolo[1,5-a]pyrimidin-7-yl)acetate (5), which has been isolated and its crystal structure determined by X-ray diffraction. The X-ray analysis of the single crystals of [Cu(4)2(H2O)2] obtained from the slow evaporation of EtOH and MeOH, separately, revealed the formation of "solvent induced" polymorphs C1 and C2, respectively. The primary supramolecular synthon for C1 and C2 are six membered ring, and square shaped hydrogen bonded architecture, respectively. The self-assembly of such synthons resulted in a two dimensional hydrogen bonded sheet supported by OH⋯O interactions. In addition, the antioxidant properties of the ligands and its complexes were evaluated in vitro using 1,1-diphenyl-2-picrylhydrazyl acid, 2,2'-azino-bis (3-ethylbenzothiazoline-6 sulfonic acid radical scavenging methods and ferric reducing antioxidant power.
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