Related Experiment Video
Updated: Jul 4, 2025
![Measuring the Spin-Lattice Relaxation Magnetic Field Dependence of Hyperpolarized [1-13C]pyruvate](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F59399.jpg&w=3840&q=50)
Measuring the Spin-Lattice Relaxation Magnetic Field Dependence of Hyperpolarized [1-13C]pyruvate
Published on: September 13, 2019
Ultrafast excited state relaxation dynamics of pyran-based D-π-A systems: solvent polarity controls the triplet state
Pookalavan Karicherry Vineetha1, Chinju Govind2, Venugopal Karunakaran2,3
1Department of Applied Chemistry and Inter-University Centre for Nanomaterials and Devices, CUSAT, Kochi 682022, Kerala, India. manoj.n@cusat.ac.in.
Abstract:
The excited state relaxation dynamics of V-shaped D-π-A systems having 4H-pyranylidene appended barbituric acid as an acceptor and diphenylamine (TPAPBA) and diethyl amine (EAPBA) as donors were investigated using steady-state and time-resolved spectroscopy along with theoretical optimization. The steady-state photophysical characterization exhibited the bathochromic shift of the emission maximum (∼6400 cm-1) and large change in the dipole moment (∼24D) with an increase of solvent polarity, reflecting the occurrence of the intramolecular charge transfer state (ICT) in the excited state. The nanosecond and femtosecond transient absorption spectra of these derivatives in a non-polar solvent, toluene, reveal that the excited state relaxation pathway involving a local excited state (LE) decayed to ICT followed by the formation of a twisted ICT state by conformational relaxation, finally leading to the triplet state. The lack of observation of a triplet state in the polar solvent, acetonitrile, signifies that the relaxation dynamics of V-shaped triads in the excited state are influenced by the polarity of the solvent.
More Related Videos
Related Concept Videos
¹H NMR of Conformationally Flexible Molecules: Temporal Resolution
Photochemical Electrocyclic Reactions: Stereochemistry
Selection Rules: Photochemical Activation
Atomic Nuclei: Types of Nuclear Relaxation
In spin–lattice or longitudinal relaxation, the excited spins exchange energy with the surrounding lattice as they return to the lower energy level. Among several mechanisms that contribute to spin–lattice relaxation, magnetic dipolar interactions are significant. Here, the excited nucleus transfers...
Deactivation Processes: Jablonski Diagram
π Electron Effects on Chemical Shift: Aromatic and Antiaromatic Compounds
Double Resonance Techniques: Overview
Spin decoupling is usually achieved by...

