Related Experiment Video
Updated: Jul 11, 2026
09:33
Phthalic Acid Ester-Binding DNA Aptamer Selection, Characterization, and Application to an Electrochemical Aptasensor
Published on: March 21, 2018
Dibenzo[a,c]phenazine: a polarity-insensitive hydrogen-bonding probe
Debarati Dey1, Adity Bose, Dhananjay Bhattacharyya
1Chemical Sciences Division, and Biophysics Division, Saha Institute of Nuclear Physics, 1/AF, Bidhannagar, Kolkata 700 064, India.
The Journal of Physical Chemistry. A
|September 26, 2007
Summary
Dibenzo[a,c]phenazine (DBPZ) acts as a unique hydrogen-bonding probe, sensing hydrogen-bond donating solvents regardless of polarity. Its structure prevents polarity sensing but allows efficient excited-state hydrogen bonding.
Area of Science:
- Photochemistry
- Molecular Probes
- Spectroscopy
Background:
- Phenazine derivatives are used in chemical sensing.
- Understanding molecular interactions in different media is crucial.
Purpose of the Study:
- To investigate the photophysical properties of dibenzo[a,c]phenazine (DBPZ).
- To evaluate DBPZ as a probe for solvent interactions, particularly hydrogen bonding.
Main Methods:
- Steady-state absorption and fluorescence spectroscopy.
- Time-resolved fluorescence studies.
- Theoretical calculations.
Main Results:
- DBPZ is insensitive to solvent polarity but forms strong excited-state hydrogen bonds.
- Hydrogen-bond formation is dependent on solvent size and donor ability.
- Steric hindrance in DBPZ prevents solvent accessibility to nitrogen atoms, explaining polarity insensitivity.
Conclusions:
- DBPZ functions as a selective sensor for hydrogen-bond donating solvents.
- Its unique structure allows it to probe hydrogen bonding independently of dielectric properties.
More Related Videos
Related Concept Videos
01:20¹³C NMR: Distortionless Enhancement by Polarization Transfer (DEPT)
When proton-coupled carbon-13 spectra are simplified by a broadband proton decoupling technique, structural information about the coupled protons is lost. Distortionless enhancement by polarization transfer (DEPT) is a technique that provides information on the number of hydrogens attached to each carbon in a molecule. While the DEPT experiment utilizes complex pulse sequences, the pulse delay and flip angle are specifically manipulated. The resulting signals have different phases depending on...
01:37NMR 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...
00:26Hydrogen Bonds
Hydrogen BondsHydrogen bonds are weak attractions between atoms that have formed other chemical bonds. One of these atoms is electronegative, like oxygen, and has a partial negative charge. The other is a hydrogen atom that has bonded with another electronegative atom and has a partial positive charge.Hydrogen Bonds Control the World!Because hydrogen has very weak electronegativity when it binds with a strongly electronegative atom, such as oxygen or nitrogen, electrons in the bond are...
01:04Hydrogen Bonds
A hydrogen bond is formed when a weakly positive hydrogen atom already bonded to one electronegative atom (for example, the oxygen in the water molecule) is attracted to another electronegative atom from another polar molecule, such as water (H2O), hydrogen fluoride (HF), or ammonia (NH3). The huge electronegativity difference between the H atom (2.1) and the atom to which it is bonded (4.0 for an F atom, 3.5 for an O atom, or 3.0 for an N atom), combined with the very small size of an H atom...
01:15¹H NMR of Conformationally Flexible Molecules: Variable-Temperature NMR
The axial and equatorial protons in cyclohexane can be distinguished by performing a variable-temperature NMR experiment. In this process, except for one proton, the remaining eleven protons are replaced by deuterium. The deuterium substitution avoids the possible peak splitting caused by the spin-spin coupling between the adjacent protons. The remaining proton flips between the axial and equatorial positions.
01:192D NMR: Heteronuclear Single-Quantum Correlation Spectroscopy (HSQC)
Heteronuclear single-quantum correlation spectroscopy (HSQC) is a 2D NMR technique that reveals one-bond correlations between hydrogen and a heteronucleus. The HSQC experiment is similar to the heteronuclear correlation experiment (HETCOR) but is more sensitive. In the HSQC spectrum, the proton chemical shift is plotted on the horizontal F2 axis, while the 13C chemical shift is plotted on the vertical F1 axis. The corresponding proton and 13C spectra are also shown. The HSQC contour plot does...