Related Experiment Video
Updated: Jun 27, 2026

Magnetometric Characterization of Intermediates in the Solid-State Electrochemistry of Redox-Active Metal-Organic Frameworks
Published on: June 9, 2023
Magnetic observation of anion binding in iron coordination complexes: toward spin-switching chemosensors
Zhaoping Ni1, Matthew P Shores
1Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, USA.
Abstract:
Many spin-crossover complexes exhibit high sensitivity to small environmental changes. Here, we demonstrate proof-of-concept exploitation of this property to report anion binding events in solution. Dichloromethane solutions of the cationic receptor complex [Fe(H(2)bip)(3)](BPh(4))(2) (bip = 2,2'-bi-1,4,5,6-tetrahydropyrimidine) (1) undergo subtle color changes at room temperature when interrogated by anions capable of hydrogen bonding interactions. Significantly, at -40 degrees C, these secondary binding interactions cause a change from a high- to low-spin state that is qualitatively linked to the strength of the host-guest interaction. The anion recognition property is combined with spin-state switching in a synergistic fashion and offers the possibility of using magnetometry to report host-guest interactions.
More Related Videos
11:19Site Directed Spin Labeling and EPR Spectroscopic Studies of Pentameric Ligand-Gated Ion Channels
Published on: July 4, 2016
15:03Synthesis of Functionalized Magnetic Nanoparticles, Their Conjugation with the Siderophore Feroxamine and its Evaluation for Bacteria Detection
Published on: June 16, 2020
Related Concept Videos
Colors 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 eye.
Valence Bond Theory
Metal-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...
π Electron Effects on Chemical Shift: Overview
Structural 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 be...
Crystal 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...