Related Experiment Video
Updated: Dec 27, 2025
![[DPEPhosbcpCu]PF6: A General and Broadly Applicable Copper-Based Photoredox Catalyst](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F59739.jpg&w=3840&q=50)
[DPEPhosbcpCu]PF6: A General and Broadly Applicable Copper-Based Photoredox Catalyst
Published on: May 21, 2019
Comparison Study of the Site-Effect on Regioisomeric Pyridyl-Pyrene Conjugates: Synthesis, Structures, and
Qing Lu1, Goutam Kumar Kole2, Alexandra Friedrich2
1State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China.
Abstract:
To investigate the "site effect" of pyridyl substituents on a pyrene core, four regioisomeric monopyridyl-pyrene (1-4) and five regioisomeric dipyridyl-pyrene (5-9) conjugates were synthesized and characterized and their structures confirmed by single-crystal X-ray diffraction. The photophysical properties and related frontier orbital features of these compounds have been studied both experimentally and theoretically and demonstrate the dependence of the properties of the compounds on the position of substitution of the pyridyl moieties connecting to the pyrene core. It was found that the absorption spectra of 2- and 4-substituted pyrene derivatives display similar and weak influence on the S2 ← S0 excitations, whereas they are quite different from those of 1-substituted isomers. The emission spectra of 1- and 4-substituted pyrenes are quite similar, whereas those of 2-substituted isomers display the largest bathochromic shift. The 1,6-disubstituted compound 5 exhibits a near-unity emission quantum yield in solution, which is nearly three times higher than those of other regioisomeric dipyridyl-pyrenes. In addition, the tetrasubstituted 1,6-dipyridyl-3,8-di-n-butyl-pyrene (10) exhibits the highest solid-state quantum yield of 0.24 among all of the 10 pyridyl-pyrenes prepared in this study.
More Related Videos
14:11Synthesis of pH Dependent Pyrazole, Imidazole, and Isoindolone Dipyrrinone Fluorophores using a Claisen-Schmidt Condensation Approach
Published on: June 10, 2021
06:16Monitoring the Effects of Illumination on the Structure of Conjugated Polymer Gels Using Neutron Scattering
Published on: December 21, 2017
Related Concept Videos
Photochemical Electrocyclic Reactions: Stereochemistry
Selection Rules: Photochemical Activation
Stability of Conjugated Dienes
A comparison of the enthalpies of hydrogenation of dienes reveals that conjugated dienes release less heat on hydrogenation, rendering them more stable than their nonconjugated analogs.
UV–Vis Spectroscopy of Conjugated Systems
One of the factors influencing λmax is the extent of conjugation in...
Thermal Electrocyclic Reactions: Stereochemistry
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.
Structure of Conjugated Dienes
Conjugated dienes are compounds characterized by the presence of alternating double and single bonds. In a conjugated system like 1,3-butadiene, the unhybridized 2p orbital on each carbon overlaps continuously, allowing the π electrons to be delocalized across the entire molecule. In contrast, this type of overlap does not occur in cumulated and isolated dienes, such as 2,3-pentadiene and 1,4-pentadiene, respectively. Instead, the π electrons remain localized between the double...
UV–Vis Spectroscopy: Woodward–Fieser Rules