Related Experiment Video
Updated: Sep 23, 2025
Hyperspectral Imaging as a Tool to Study Optical Anisotropy in Lanthanide-Based Molecular Single Crystals
Published on: April 14, 2020
Color tuning and white light emission by codoping in isostructural homochiral lanthanide metal-organic frameworks
Wenbo Wang1, Ruiying Wang2, Yafang Ge1
1College of Chemistry and Molecular Engineering, Zhengzhou University Zhengzhou 450001 P. R. China wbl@zzu.edu.cn +86 0371 67783126.
Abstract:
Four lanthanide-based homochiral metal-organic frameworks (Ln-HMOFs), {[Ln2(HL)2(H2O)4]·2Cl·5H2O} [Ln = Gd (1), Eu (2), Tb (3) and Dy (4)], have been synthesized through solvothermal reactions of chiral ligand (S)-5-(((1-carboxyethyl)amino)methyl)isophthalic acid (H3L) with corresponding LnCl3·6H2O. They are binodal (3,6)-connected frameworks with kgd nets based on binuclear cluster units and zwitterionic (HL)2- linkers. Considering the isostructuralism of these Ln-HMOFs as well as the blue emission of compound 1 and the strong typical Eu3+ and Tb3+ emissions of compounds 2 and 3, single-phase mixed-lanthanide HMOFs have been prepared by doping of Ln3+ into the Ln-HMOFs to modulate light-emitting color. Interestingly, the bimetallic doped Eu/Tb-HMOFs [(Eu Tb1- )2(HL)2(H2O)4]·2Cl·5H2O display a fluent change of light-emitting color among green, yellow, orange, orange-red, and red by adjusting the doping concentration of Eu3+ ions into the Tb-HMOF. Very importantly, the trimetallic doped Eu/Gd/Tb-HMOF [(Eu0.1388Gd0.6108Tb0.2504)2(HL)2(H2O)4]·2Cl·5H2O emits white light upon excitation at 355 nm, whose emission can also be switched between different colors when excited with different ultraviolet light. Furthermore, the fluorescence response of Tb-HMOF to various usual metal ions, and especially fluorescent sensing behaviours to Fe3+, Cr3+ and Al3+ have been preliminarily investigated.
Related Concept Videos
03:02Colors and Magnetism
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human...
02:58Crystal Field Theory - Octahedral Complexes
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
02:52Stereoisomerism
Isomers are different chemical species that have the same chemical formula.
Transition metal complexes often exist as geometric isomers, in which the same atoms are connected through the same types of bonds but with differences in their orientation in space. Coordination complexes with two different ligands in the cis and trans positions from a ligand of interest form isomers. For example, the octahedral [Co(NH3)4Cl2]+ ion has two isomers (Figure 1) In the cis...
02:34Structural Isomerism
Isomers are different chemical species that have the same chemical formula. Structural isomerism of coordination compounds can be divided into two subcategories, the linkage isomers and coordination-sphere isomers.
Linkage isomers occur when the coordination compound contains a ligand that can bind to the transition metal center through two different atoms. For example, the CN− ligand can bind through the carbon atom or through the nitrogen atom. Similarly, SCN− can...