Related Experiment Video
Updated: Aug 12, 2026
08:15
Synthesis of Nine-atom Deltahedral Zintl Ions of Germanium and their Functionalization with Organic Groups
Published on: February 11, 2012
Electron density study of 2H-chromene-2-thione
Parthapratim Munshi1, T N Guru Row
1Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore - 560012, India.
Acta Crystallographica. Section B, Structural Science
|November 29, 2002
Summary
This study determined the charge-density distribution in 2H-chromene-2-thione (2-thiocoumarin) using X-ray diffraction. The crystal
Area of Science:
- Crystallography
- Chemical Physics
- Materials Science
Background:
- Understanding charge-density distribution is crucial for predicting molecular properties and reactivity.
- 2H-chromene-2-thione (2-thiocoumarin) is a heterocyclic compound with potential applications in various chemical fields.
- Accurate charge density studies provide insights into bonding characteristics and intermolecular interactions.
Purpose of the Study:
- To determine the experimental charge-density distribution of 2H-chromene-2-thione (2-thiocoumarin) at 90 K.
- To analyze the topological properties of the molecular electron density, including bond critical points.
- To evaluate the molecular dipole moment in the crystalline state and compare it with theoretical calculations.
Main Methods:
- X-ray diffraction data collection at cryogenic temperature (90 K) using a CCD detector.
- High-resolution data acquisition with a resolution of sin(theta)/lambda < 1.08 A(-1).
- Refinement using a multipolar-atom density model against 6908 reflections (I > 2sigma(I)) to generate difference Fourier maps.
Main Results:
- The charge-density distribution of 2H-chromene-2-thione was successfully determined.
- Analysis of bond critical points revealed detailed bonding information within the molecule.
- The experimental molecular dipole moment in the crystal was found to be higher than theoretically predicted values.
Conclusions:
- The experimental charge density analysis provides a precise understanding of the electronic structure of 2H-chromene-2-thione.
- The discrepancy between experimental and theoretical dipole moments highlights the importance of crystal packing effects.
- This study contributes valuable data for further theoretical and experimental investigations of thiocoumarin derivatives.
More Related Videos
Related Concept Videos
02:58Crystal Field Theory - Octahedral Complexes
Crystal Field Theory
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...
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...
02:46Crystal Field Theory - Tetrahedral and Square Planar Complexes
Tetrahedral 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,...
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,...
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.
02:46Electron Configurations
Electron configurations and orbital diagrams can be determined by applying the Aufbau principle (each added electron occupies the subshell of lowest energy available), Pauli exclusion principle (no two electrons can have the same set of four quantum numbers), and Hund’s rule of maximum multiplicity (whenever possible, electrons retain unpaired spins in degenerate orbitals).
The relative energies of the subshells determine the order in which atomic orbitals are filled (1s, 2s, 2p, 3s, 3p, 4s,...
The relative energies of the subshells determine the order in which atomic orbitals are filled (1s, 2s, 2p, 3s, 3p, 4s,...
01:27Inductive Effects on Chemical Shift: Overview
The protons in unsubstituted alkanes are strongly shielded with chemical shifts below 1.8 ppm. Methine, methylene, and methyl protons appear at approximately 1.7, 1.2 and 0.7 ppm, while the proton signal from methane appears at 0.23 ppm. An electronegative substituent, such as chlorine, withdraws the electron density from the protons, increasing their chemical shift. Progressive substitution of the hydrogens in methane by chlorine shifts the proton signals increasingly downfield, to 3.05 ppm in...
01:18Aromatic Hydrocarbon Cations: Structural Overview
Cycloheptatriene is a neutral monocyclic unsaturated hydrocarbon that consists of an odd number of carbon atoms and an intervening sp3 carbon in the ring. The three double bonds in the ring correspond to 6 π electrons, which is a Huckel number, and therefore satisfies the criteria of 4n + 2 π electrons. However, the intervening sp3 carbon disrupts the continuous overlap of p orbitals. As a result, cycloheptatriene is not aromatic.
Removing one hydrogen from the intervening CH2 group with both...
Removing one hydrogen from the intervening CH2 group with both...