Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Valence Bond Theory02:42

Valence Bond Theory

Coordination compounds and complexes exhibit different colors, geometries, and magnetic behavior, depending on the metal atom/ion and ligands from which they are composed. In an attempt to explain the bonding and structure of coordination complexes, Linus Pauling proposed the valence bond theory, or VBT, using the concepts of hybridization and the overlapping of the atomic orbitals. According to VBT, the central metal atom or ion (Lewis acid) hybridizes to provide empty orbitals of suitable...
Colors and Magnetism03:02

Colors 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.
Spin–Spin Coupling: Two-Bond Coupling (Geminal Coupling)01:20

Spin–Spin Coupling: Two-Bond Coupling (Geminal Coupling)

Two NMR-active nuclei bonded to a central atom can be involved in geminal or two-bond coupling. Geminal coupling is commonly seen between diastereotopic protons in chiral molecules and unsymmetrical alkenes, among others.
The central atom need not be NMR-active because its electrons are affected by the electron polarization of the spin-active atoms. However, spin information is transmitted less effectively than in one-bond coupling, and 2J values are usually weaker than 1J values. The energy of...
Spin–Spin Coupling: One-Bond Coupling01:17

Spin–Spin Coupling: One-Bond Coupling

Coupling interactions are strongest between NMR-active nuclei bonded to each other, where spin information can be transmitted directly through the pair of bonding electrons. While nuclei polarize their electrons to the opposite spins, the bonding electron pair has opposite spins. Configurations with antiparallel nuclear spins are expected to be lower in energy. When coupling makes antiparallel states more favorable, J is considered to have a positive value. The one-bond coupling constant, 1J,...
Spin–Spin Coupling: Three-Bond Coupling (Vicinal Coupling)01:22

Spin–Spin Coupling: Three-Bond Coupling (Vicinal Coupling)

Vicinal or three-bond coupling is commonly observed between protons attached to adjacent carbons. Here, nuclear spin information is primarily transferred via electron spin interactions between adjacent C‑H bond orbitals. This generally favors the antiparallel arrangement of spins, so 3J values are usually positive.
The extent of coupling depends on the C‑C bond length, the two H‑C‑C angles, any electron-withdrawing substituents, and the dihedral angle between the involved orbitals. The...
Spin–Spin Coupling Constant: Overview01:08

Spin–Spin Coupling Constant: Overview

In bromoethane, the three methyl protons are coupled to the two methylene protons that are three bonds away. In accordance with the n+1 rule, the signal from the methyl protons is split into three peaks with 1:2:1 relative intensities. The methylene protons appear as a quartet, with the relative intensities of 1:3:3:1.
Qualitatively, any spin plus-half nucleus polarizes the spins of its electrons to the minus-half state. Consequently, the paired electron in the hydrogen–carbon bond must have a...

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Fe(0)-catalyzed alkyne carboxylation with CO<sub>2</sub> involving spin crossover.

Chemical communications (Cambridge, England)·2026
Same author

4D-Printed Spin Crossover Metamaterials with Giant Programmable Positive or Negative Thermal Expansion.

Advanced materials (Deerfield Beach, Fla.)·2026
Same author

Conserved Kir channel mechanisms governing intrinsic excitability in human and rodent parvalbumin neurons.

Communications biology·2026
Same author

The future of digital innovation in transforming food safety systems in the developing world.

NPJ science of food·2026
Same author

Group I metabotropic glutamate receptors differentially modulate excitatory transmission across interneuron types in the human cortex.

Frontiers in synaptic neuroscience·2026
Same author

Spatial characterization of backpropagating action potential-evoked Ca<sup>2+</sup> signals in human cortical layer 2/3 pyramidal neurons.

Frontiers in synaptic neuroscience·2026

Related Experiment Video

Updated: Jun 28, 2026

Preparation of 6-aminocyclohepta-2,4-dien-1-one Derivatives via Tricarbonyl(tropone)iron
07:56

Preparation of 6-aminocyclohepta-2,4-dien-1-one Derivatives via Tricarbonyl(tropone)iron

Published on: August 12, 2019

A two-step spin crossover mononuclear iron(II) complex with a [HS-LS-LS] intermediate phase.

Sylvestre Bonnet1, Maxime A Siegler, José Sánchez Costa

  • 1Leiden Institute of Chemistry, Leiden University, RA2300, Leiden, The Netherlands.

Chemical Communications (Cambridge, England)
|November 11, 2008
PubMed
Summary

This study reveals a new iron(II) complex exhibiting two-step spin crossover behavior. It displays two successive phase transitions and an ordered intermediate phase with a unique [High-Spin-Low-Spin-Low-Spin] motif.

More Related Videos

Molten-Salt Synthesis of Complex Metal Oxide Nanoparticles
08:43

Molten-Salt Synthesis of Complex Metal Oxide Nanoparticles

Published on: October 27, 2018

Study of Protein Dynamics via Neutron Spin Echo Spectroscopy
08:03

Study of Protein Dynamics via Neutron Spin Echo Spectroscopy

Published on: April 13, 2022

Related Experiment Videos

Last Updated: Jun 28, 2026

Preparation of 6-aminocyclohepta-2,4-dien-1-one Derivatives via Tricarbonyl(tropone)iron
07:56

Preparation of 6-aminocyclohepta-2,4-dien-1-one Derivatives via Tricarbonyl(tropone)iron

Published on: August 12, 2019

Molten-Salt Synthesis of Complex Metal Oxide Nanoparticles
08:43

Molten-Salt Synthesis of Complex Metal Oxide Nanoparticles

Published on: October 27, 2018

Study of Protein Dynamics via Neutron Spin Echo Spectroscopy
08:03

Study of Protein Dynamics via Neutron Spin Echo Spectroscopy

Published on: April 13, 2022

Area of Science:

  • Coordination Chemistry
  • Materials Science
  • Solid-State Chemistry

Background:

  • Spin crossover (SCO) complexes are molecular switches responding to external stimuli.
  • Mononuclear iron(II) complexes are extensively studied for their SCO properties.
  • Understanding SCO mechanisms is crucial for developing new functional materials.

Purpose of the Study:

  • To synthesize and characterize a novel mononuclear iron(II) complex.
  • To investigate the spin crossover behavior of this new complex.
  • To elucidate the nature of the phase transitions and the intermediate phase.

Main Methods:

  • Magnetic susceptibility measurements to probe spin states.
  • Single-crystal X-ray diffraction to determine crystallographic structures.
  • Calorimetric analysis (DSC) to identify phase transitions.

Main Results:

  • The complex exhibits a two-step spin crossover phenomenon.
  • Two successive first-order phase transitions were observed.
  • An ordered intermediate phase characterized by a repeating [High-Spin-Low-Spin-Low-Spin] motif was identified.

Conclusions:

  • The new iron(II) complex displays complex spin crossover dynamics.
  • The unprecedented [HS-LS-LS] motif provides new insights into SCO mechanisms.
  • This work contributes to the design of advanced molecular materials with tunable properties.