Related Experiment Video
Updated: Jul 14, 2026
11:44
Using Cyclic Voltammetry, UV-Vis-NIR, and EPR Spectroelectrochemistry to Analyze Organic Compounds
Published on: October 18, 2018
[Spectroscopic study on the binding of Mn(II) to EHPG]
Hai-peng Li1, Chun-gui Zhao, Xiao-li Li
1Key Lab of Chemical Biology and Molecular Engineering of Ministry of Education, Shanxi University, Taiyuan 030006, China.
Guang Pu Xue Yu Guang Pu Fen Xi = Guang Pu
|May 23, 2007
Summary
The interaction between ethylene-N,N'-bis(o-hydroxyphenylglycine) (EHPG) and manganese (II) ions was studied. Results indicate a 1:1 complex formation with a weak binding interaction, suggesting potential applications in manganese ion detection.
Area of Science:
- Coordination Chemistry
- Spectroscopy
Context:
- Manganese (II) ions are essential trace elements involved in various biological processes.
- Ethylene-N,N'-bis(o-hydroxyphenylglycine) (EHPG) is a chelating agent with potential applications in metal ion sensing.
- Understanding the binding characteristics of EHPG with Mn(II) is crucial for developing selective metal ion detection methods.
Purpose:
- To investigate the complexation reaction between EHPG and Mn(II) ions.
- To determine the stoichiometry, binding affinity, and spectral properties of the Mn(II)-EHPG complex.
- To characterize the interaction using fluorescence and UV-Vis difference spectroscopy.
Summary:
- The study investigated the interaction of ethylene-N,N'-bis(o-hydroxyphenylglycine) (EHPG) with manganese (II) ions in a Hepes buffer at pH 7.4 and room temperature.
- Spectroscopic analysis revealed a 1:1 molar ratio for the complex formation.
- The disassociation constant was determined to be (1.36 ± 0.21) x 10(-5), indicating a weak binding interaction between Mn(II) and EHPG.
Impact:
- The findings provide quantitative data on the Mn(II)-EHPG interaction, contributing to the understanding of metal-ligand complexation.
- The characterized spectral changes can be utilized for the development of sensitive and selective methods for Mn(II) ion detection.
- This research lays the groundwork for potential applications of EHPG in environmental monitoring or biological sensing of manganese.
Related Concept Videos
03:02Colors and Magnetism
Color in Coordination Complexes
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.
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.
01:13¹H NMR: Complex Splitting
A proton M that is coupled to a proton X results in doublet signals for M. However, NMR-active nuclei can be simultaneously coupled to more than one nonequivalent nucleus. When M is coupled to a second proton A, such as in styrene oxide, each peak in the doublet is split into another doublet.
Splitting diagrams or splitting tree diagrams are routinely used to depict such complex couplings. While drawing splitting diagrams, the splitting with the larger coupling constant is usually applied first.
Splitting diagrams or splitting tree diagrams are routinely used to depict such complex couplings. While drawing splitting diagrams, the splitting with the larger coupling constant is usually applied first.
01:17Electron Paramagnetic Resonance (EPR) Spectroscopy: Organic Radicals
Ideally, an unpaired electron shows a single peak in the EPR spectrum due to the transition between the two spin energy states. However, coupling interactions can occur between the spins of the unpaired electron and any neighboring spin-active nuclei. This hyperfine coupling results in hyperfine splitting, where the EPR signal is split into multiplets. The signals split into 2nI + 1 peaks, where n is the number of equivalent nuclei and I is the nuclear spin. These splitting patterns provide...
01:182D NMR: Overview of Heteronuclear Correlation Techniques
Heteronuclear correlation spectroscopy is an analytical technique that investigates the coupling between different types of nuclei, often a proton and an X-nucleus, such as carbon-13 or nitrogen-15. This method is commonly used in nuclear magnetic resonance (NMR) spectroscopy to gain insights into complex chemical compounds' structural and compositional aspects. A typical heteronuclear correlation spectrum displays X-nucleus chemical shifts on one axis and a proton spectrum on the other axis.
00:48¹H NMR of Labile Protons: Deuterium (²H) Substitution
This lesson illustrates the role of deuterium substitution in simplifying the NMR spectrum of compounds comprising labile protons. One method employed is the use of deuterium. Amongst the three isotopes of hydrogen, deuterium (2H) has a nucleus composed of one proton and one neutron. When the D2O solvent is added to a pure dry ethanol solution, its labile proton is substituted with deuterium.
01:19NMR Spectroscopy Of Amines
In proton NMR spectroscopy, primary amines and secondary amines showcase their N–H protons as a broad signal in the chemical shift range between δ 0.5 and 5 ppm. The exact position in this range depends on several factors, including sample concentration, hydrogen bonding, and the type of solvent used. Since amine protons undergo fast proton exchange in solution, the protons are labile and therefore do not participate in any splitting with adjacent protons. Thus, the observed peak is broad and...