Related Experiment Video
Updated: Mar 12, 2026
Author Spotlight: Experimental Approaches for the Synthesis of Low-Valent Metal-Organic Frameworks from Multitopic Phosphine Linkers
Published on: May 12, 2023
Ferro- or antiferromagnetic interactions controlled by ditopic or chelating auxiliary ligands in 3D metal-organic
Hua Tian1, Ai-Ling Cheng2, En-Qing Gao2
1Shanghai Key Laboratory of Green Chemistry and Chemical Processes, College of Chemistry and Molecular Engineering, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062, China. eqgao@chem.ecnu.edu.cn and School of Chemistry and Chemical Engineering, Ningxia University, Yinchuan 750021, China.
Abstract:
Three 3D Co(ii) metal-organic frameworks of the general formula [Co(DNNDC)(NN)]n were reported, where DNNDC = 1,5-dinitronaphthalene-3,7-dicarboxylate and NN = bridging or chelating dipyridyl ligands. The MOFs exhibit similar 3D [Co(DNNDC)]n frameworks in which double-carboxylate-bridged [Co(OCO)2]n chains are cross-linked by naphthalene backbones. The bridging dipyridyl ligands [4,4'-bipyridine (bpy) and 1,2-bis(4-pyridyl)ethane (bpe)] serve as additional linkers between the chains to generate a reinforced framework with new net topology, while the chelating ligand 1,10-phenanthroline (phen) reinforces the frameworks through π-π stacking and C-HO interactions. Remarkably, varying the auxiliary ligand leads to a change in the sign of the magnetic exchange through the double carboxylate bridge: the MOFs with the ditopic bpy and bpe ligands show ferromagnetic interactions, while the one with the chelating phen ligand shows antiferromagnetic exchange. The difference in magnetic exchange is attributable to the subtle change in the coordination conformation of the carboxylate bridge.
More Related Videos
Related Concept Videos
02:51Metal-Ligand Bonds
In these complexes, transition metals form coordinate covalent bonds, a kind of Lewis acid-base interaction in which both of the electrons in the bond are contributed by a donor (Lewis base) to an electron acceptor (Lewis acid). The Lewis acid in...
02:42Valence Bond Theory
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...
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...
01:19Complexation Equilibria: The Chelate Effect
02:46Crystal Field Theory - Tetrahedral and Square Planar Complexes
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...