Related Experiment Video

Updated: Jun 12, 2026

Synthesis of pH Dependent Pyrazole, Imidazole, and Isoindolone Dipyrrinone Fluorophores using a Claisen-Schmidt Condensation Approach
14:11

Synthesis of pH Dependent Pyrazole, Imidazole, and Isoindolone Dipyrrinone Fluorophores using a Claisen-Schmidt Condensation Approach

Published on: June 10, 2021

Degenerate four-wave mixing in organic azo dyes chrysoidin and benzopurpurin 4B

S Mailhot, P Galarneau, R A Lessard

    Applied Optics
    |June 12, 2010
    PubMed

    More Related Videos

    Synthesis of Wavelength-shifting DNA Hybridization Probes by Using Photostable Cyanine Dyes07:44

    Synthesis of Wavelength-shifting DNA Hybridization Probes by Using Photostable Cyanine Dyes

    Published on: July 6, 2016

    Cercosporin-Photocatalyzed [4+1]- and [4+2]-Annulations of Azoalkenes Under Mild Conditions07:12

    Cercosporin-Photocatalyzed [4+1]- and [4+2]-Annulations of Azoalkenes Under Mild Conditions

    Published on: July 17, 2020

    Related Concept Videos

    Aryldiazonium Salts to Azo Dyes: Diazo Coupling01:11

    Aryldiazonium Salts to Azo Dyes: Diazo Coupling

    The reaction of weakly electrophilic aryldiazonium (also called arenediazonium) salts with highly activated aromatic compounds leads to the formation of products with an —N=N— link, called an azo linkage. This reaction, presented in Figure 1, is known as diazo coupling and occurs without the loss of the nitrogen atoms of the aryldiazonium salt. Highly activated aromatic compounds such as phenols or arylamines favor the diazo coupling reaction. The coupling generally occurs at the para position.
    Photochemical Electrocyclic Reactions: Stereochemistry01:26

    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
    NMR Spectroscopy of Benzene Derivatives01:37

    NMR Spectroscopy of Benzene Derivatives

    Simple unsubstituted benzene has six aromatic protons, all chemically equivalent. Therefore, benzene exhibits only a singlet peak at δ 7.3 ppm in the 1H NMR spectrum. The observed shift is far downfield because the aromatic ring current strongly deshields the protons. Any substitution on the benzene ring makes the aromatic protons nonequivalent, and the protons split each other. The peak is, therefore, no longer a singlet and the splitting pattern and their associated coupling constants depend...
    π Electron Effects on Chemical Shift: Aromatic and Antiaromatic Compounds01:14

    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 annulenes. In...
    IR Absorption Frequency: Hybridization01:21

    IR Absorption Frequency: Hybridization

    Hydrocarbons such as alkanes, alkenes, and alkynes show characteristic C–H stretching absorption bands. These IR stretching frequencies depend on the hybridization of the involved carbon atom and can be explained in terms of the s character of each hybridized atomic orbital.
    Among the sp, sp2, and sp3 hybridized orbitals, sp orbitals have the maximum s character (50%). Consequently, the electrons are held more closely to the nucleus, resulting in stronger and shorter C–H bonds that stretch at a...
    Electron Paramagnetic Resonance (EPR) Spectroscopy: Organic Radicals01:17

    Electron 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...