Uranium(VI) coordination polymers with pyromellitate ligand: Unique 1D channel structures and diverse fluorescence

•Three new coordination polymers of U(VI) with pyromellitic acid (H4btca).•Structures from a 2D layer to 3D frameworks with unique 1D channels.•Unusual µ5-(η1:η2:η1:η2:η1) coordination mode of btca ligand.•Vibrational modes, thermal stabilities and luminescent properties reported.

Three new coordination polymers of uranium(VI) with pyromellitic acid (H4btca) have been synthesized and structurally characterized. (ED)[(UO2)(btca)]·(DMSO)·3H2O (1) (ED=ethylenediammonium; DMSO=dimethylsulfoxide) has a lamellar structure with intercalation of ED and DMSO. (NH4)2[(UO2)6O2(OH)6(btca)]·~6H2O (2) has a 3D framework built from 7-fold coordinated uranyl trinuclear units and btca ligands with 1D diamond-shaped channels (~8.5 Å×~8.6 Å). [(UO2)2(H2O)(btca)]·4H2O (3) has a 3D network constructed by two types of 7-fold coordinated uranium polyhedron. The unique μ5-coordination mode of btca in 3 enables the formation of 1D olive-shaped large channels (~4.5 Å×~19 Å). Vibrational modes, thermal stabilities and fluorescence properties have been investigated.

Graphical abstractTable of content: three new uranium(VI) coordination polymers with pyromellitic acid (H4btca) have been synthesized via room temperature and hydrothermal synthesis methods, and structurally characterized. Two to three dimensional (3D) frameworks are revealed. All 3D frameworks have unique 1D large channels. Their vibrational modes, thermal stabilities and photoluminescence properties have been investigated.Figure optionsDownload full-size imageDownload as PowerPoint slide