Search research articles

ABOUT JoVE

Overview Leadership Blog JoVE Help Center

AUTHORS

Publishing Process Editorial Board Scope & Policies Peer Review FAQ Submit

LIBRARIANS

Testimonials Subscriptions Access Resources Library Advisory Board FAQ

RESEARCH

JoVE Journal Methods Collections JoVE Encyclopedia of Experiments Archive

EDUCATION

JoVE Core JoVE Business JoVE Science Education JoVE Lab Manual Faculty Resource Center Faculty Site

Terms & Conditions of Use

Related Concept Videos

π Electron Effects on Chemical Shift: Aromatic and Antiaromatic Compounds

π Electron Effects on Chemical Shift: Aromatic and Antiaromatic Compounds

In aromatic compounds, such as benzene, the circulation of (4n + 2) π-electrons sets up a diamagnetic or diatropic ring current around the perimeter of the molecule. This current induces a magnetic field that opposes the external field inside the ring and reinforces it on the outside. The protons in benzene are deshielded and exhibit high chemical shifts in the range 6.5–8.5 ppm. The shielding effect at the center of the ring is evident in complex aromatic molecules, such as...

π Electron Effects on Chemical Shift: Overview

π Electron Effects on Chemical Shift: Overview

An applied magnetic field causes loosely bound π-electrons in organic molecules to circulate, producing a local or induced diamagnetic field over a large spatial volume. As the molecules tumble in solution, the field generated by π-electrons in spherical substituents results in a zero net field. However, the net field generated by π-electrons in non-spherical substituents is not zero. The effect of this induced field depends on the orientation of the molecule with respect to B0,...

Thermal Electrocyclic Reactions: Stereochemistry

Thermal Electrocyclic Reactions: Stereochemistry

The stereochemistry of electrocyclic reactions is strongly influenced by the orbital symmetry of the polyene HOMO. Under thermal conditions, the reaction proceeds via the ground-state HOMO.
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.

Thermal and Photochemical Electrocyclic Reactions: Overview

Thermal and Photochemical Electrocyclic Reactions: Overview

Electrocyclic reactions are reversible reactions. They involve an intramolecular cyclization or ring-opening of a conjugated polyene. Shown below are two examples of electrocyclic reactions. In the first reaction, the formation of the cyclic product is favored. In contrast, in the second reaction, ring-opening is favored due to the high ring strain associated with cyclobutene formation.

Colors and Magnetism

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...

Photochemical Electrocyclic Reactions: Stereochemistry

Photochemical Electrocyclic Reactions: Stereochemistry

The absorption of UV–visible light by conjugated systems causes the promotion of an electron from the ground state to the excited state. Consequently, photochemical electrocyclic reactions proceed via the excited-state HOMO rather than the ground-state HOMO. Since the ground- and excited-state HOMOs have different symmetries, the stereochemical outcome of electrocyclic reactions depends on the mode of activation; i.e., thermal or photochemical.
Selection Rules: Photochemical Activation

You might also read

Related Articles

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

Sort by

Same author

Clustering effects on the reactivity of alkoxy radicals: rate coefficients of <sup>3</sup>(RO⋯OR) complexes accounting for multiple conformers.

Physical chemistry chemical physics : PCCP·2026

Same author

Can Accretion Products Be Formed at the Interface of Freshly Nucleated Particles?

ACS omega·2026

Same author

Triply-Linked N-Confused Porphyrin Dimers: Cross Conjugation-Mediated Expansion of π-Conjugation.

Angewandte Chemie (International ed. in English)·2026

Same author

Change of the aromatic nature through face-to-face stacking.

Chemical science·2026

Same author

Gallium phosphaketenes derived from bis(imino)acenaphthenes (bian): synthesis and reactivity towards a trityl radical and bian-gallylene.

Dalton transactions (Cambridge, England : 2003)·2026

Same author

The Electronic Structure of Planar Rhombic Co<sub>2</sub>O<sub>2</sub>.

The journal of physical chemistry. A·2026

Search research articles

Related Experiment Video

Updated: Oct 8, 2025

Photogeneration of N-Heterocyclic Carbenes: Application in Photoinduced Ring-Opening Metathesis Polymerization

Photogeneration of N-Heterocyclic Carbenes: Application in Photoinduced Ring-Opening Metathesis Polymerization

Published on: November 29, 2018

Magnetically induced ring currents in metallocenothiaporphyrins.

Rashid R Valiev^1,2, Theo Kurten², Lenara I Valiulina¹

¹Department of Optics and Spectroscopy, Tomsk State University, Tomsk, 634050, Russia.

Physical Chemistry Chemical Physics : PCCP

|January 4, 2022

Summary

This summary is machine-generated.

This study investigates the aromaticity of metallocenothiaporphyrins using current-density susceptibility tensor (CDT) calculations. Findings reveal these molecules generally follow established aromaticity rules, with a unified rule for odd/even electron systems.

More Related Videos

Accessing Valuable Ligand Supports for Transition Metals: A Modified, Intermediate Scale Preparation of 1,2,3,4,5-Pentamethylcyclopentadiene

Accessing Valuable Ligand Supports for Transition Metals: A Modified, Intermediate Scale Preparation of 1,2,3,4,5-Pentamethylcyclopentadiene

Published on: March 20, 2017

Author Spotlight: Magnetometric Characterization of Intermediates in the Solid-State Electrochemistry of Redox-Active Metal-Organic Frameworks

Author Spotlight: Magnetometric Characterization of Intermediates in the Solid-State Electrochemistry of Redox-Active Metal-Organic Frameworks

Published on: June 9, 2023

Related Experiment Videos

Last Updated: Oct 8, 2025

Photogeneration of N-Heterocyclic Carbenes: Application in Photoinduced Ring-Opening Metathesis Polymerization

Photogeneration of N-Heterocyclic Carbenes: Application in Photoinduced Ring-Opening Metathesis Polymerization

Published on: November 29, 2018

Accessing Valuable Ligand Supports for Transition Metals: A Modified, Intermediate Scale Preparation of 1,2,3,4,5-Pentamethylcyclopentadiene

Accessing Valuable Ligand Supports for Transition Metals: A Modified, Intermediate Scale Preparation of 1,2,3,4,5-Pentamethylcyclopentadiene

Published on: March 20, 2017

Author Spotlight: Magnetometric Characterization of Intermediates in the Solid-State Electrochemistry of Redox-Active Metal-Organic Frameworks

Author Spotlight: Magnetometric Characterization of Intermediates in the Solid-State Electrochemistry of Redox-Active Metal-Organic Frameworks

Published on: June 9, 2023

Area of Science:

Computational chemistry
Organic chemistry
Materials science

Background:

Metallocenothiaporphyrins are a class of organometallic compounds with potential applications in various fields.
Understanding their electronic structure and aromaticity is crucial for predicting their properties and designing new materials.

Purpose of the Study:

To investigate the aromaticity of metallocenothiaporphyrins using the gauge-including magnetically induced currents (GIMIC) method.
To determine the applicability of Hückel and Baird aromaticity rules to these systems, including those with an odd number of electrons.

Main Methods:

Calculations of the magnetically induced current-density susceptibility tensor (CDT) for various metallocenothiaporphyrins.
Application of the gauge-including magnetically induced currents (GIMIC) method.
Analysis of singlet, triplet, and high-spin states, including cationic species.

Main Results:

The study calculated the CDT for metallocenothiaporphyrins with metals V, Cr, Mn, Fe, Co, Ni, Mo, Tc, Ru, and Rh.
Most studied molecules exhibited aromatic character consistent with Hückel and Baird rules.
A unified aromaticity rule based on occupied conjugated valence orbitals was identified for odd electron systems.

Conclusions:

Metallocenothiaporphyrins generally adhere to established aromaticity principles.
A unified orbital-count rule effectively predicts aromaticity in both even and odd electron systems within this class of compounds.