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Updated: May 29, 2026

Hyperspectral Imaging as a Tool to Study Optical Anisotropy in Lanthanide-Based Molecular Single Crystals
Published on: April 14, 2020
Topological isomers in lanthanide-chloranilate coordination polymers: synthesis, structure and CO2 adsorption
Kenika Khotchasanthong1, Chombongkot Sricharoen1, Pacharapon Jearanaiwiwat1
1Thammasat University Research Unit for Multifunctional Crystalline Materials and Applications, Faculty of Science and Technology, Thammasat University Pathum Thani 12121 Thailand kc@tu.ac.th.
Abstract:
The effect of lanthanide contraction on the self-assembly of two-dimensional (2D) topological isomers in lanthanide coordination polymers (LnCPs) is presented in this work. Hydrothermal reactions involving LnCl3 and chloranilic acid (H2ca) afforded good yields of ten LnCPs with the general formula [Ln(ca)1.5(H2O)3]·xH2O (1Ln; Ln = Pr, Nd; 2Ln; Ln = Sm, Eu, Gd, Tb, Dy, Er, Tm, Yb; x = 3.5-5). The isostructural compounds crystallize in the centrosymmetric triclinic P1̄ space group and display 2D layered networks featuring topologically distinct isomers, specifically honeycomb for 1Ln and brick-wall for 2Ln. The lattice water molecules are located in interlayered spaces with the number of water molecules per formula unit increasing as the ionic radii of Ln3+ decrease. The incorporation of the semi-rigid rod 4,4'-bipyridine (4,4'-bipy) into brick-wall 2D networks aims to establish a porous 3D pillared framework, leading to the creation of an intercalation network comprising the guest 4,4'-bipy and lattice water molecules, [Ln(ca)1.5(H2O)2]·2H2O·4,4'-bipy (3Ln; Ln = Tm, Yb). The physicochemical properties of the isomers 1Ln and 2Ln were clearly illustrated, highlighting their unique structural features, thermal stability, and adsorption characteristics. At both low pressure (1 bar) and elevated pressure (up to 20 bar), the thermally activated brick-wall network 2Yb demonstrated better absorption of CO2 relative to the honeycomb network 1Pr. This study illustrates that minor variations in the size of lanthanide metal ions significantly influence the architecture and application of innovative materials through structural topological isomers.
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