Related Experiment Video
Updated: Jun 4, 2026
09:35
Preparation of a Corannulene-functionalized Hexahelicene by Copper(I)-catalyzed Alkyne-azide Cycloaddition of Nonplanar Polyaromatic Units
Published on: September 18, 2016
Spectral shifts and structures of phenol...Ar(n) clusters
Antonio Armentano1, Jiří Cerný, Mikko Riese
1The Photon Science Institute, The University of Manchester, Manchester, UK.
Physical Chemistry Chemical Physics : PCCP
|February 25, 2011
Summary
This study investigates phenol-argon clusters using laser spectroscopy. Most clusters showed red-shifted transitions, but phenolAr(3) exhibited a blue shift, with precise ionization energies determined for phenolAr(3) and phenolAr(4).
Area of Science:
- Physical Chemistry
- Spectroscopy
- Molecular Physics
Background:
- Phenol-argon clusters are model systems for studying intermolecular interactions.
- Understanding electronic states and ionization energies is crucial for molecular characterization.
Purpose of the Study:
- To investigate the electronic structure of phenol-argon clusters (n=1-6) in excited and ionic states.
- To determine the effect of argon atom addition on phenol's electronic transitions and ionization energies.
Main Methods:
- Resonance-enhanced two-photon ionization (R2PI) spectroscopy for the S(1) state.
- Photoionization efficiency (PIE) and mass-analyzed threshold ionization (MATI) spectroscopy for the cationic ground state (D(0)).
- Combination with theoretical methods for species identification.
Main Results:
- S(1)←S(0) transitions for phenol-Ar(n) (n=1, 2, 4-6) were red-shifted, while phenol-Ar(3) showed a blue shift.
- Ionization energies (IE) for phenol-Ar(3) and phenol-Ar(4) were determined as 68,077 ± 15 cm⁻¹ and 67,948 ± 15 cm⁻¹, respectively.
- Spectroscopic data confirmed the presence of major species.
Conclusions:
- Argon solvation significantly influences the electronic properties of phenol.
- The study provides detailed insights into the excited and ionic states of phenol-argon clusters.
- Combined spectroscopic and theoretical approaches are effective for cluster characterization.
![Cercosporin-Photocatalyzed [4+1]- and [4+2]-Annulations of Azoalkenes Under Mild Conditions](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F60786.jpg&w=3840&q=50)
Related Concept Videos
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...
01:14π 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...
01:02¹H NMR: Interpreting Distorted and Overlapping Signals
Spin systems where the difference in chemical shifts of the coupled nuclei is greater than ten times J are called first-order spin systems. These nuclei are weakly coupled, and their chemical shifts and coupling constant can generally be estimated from the well-separated signals in the spectrum.
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are slanted or...
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are slanted or...
01:08IR Spectrum Peak Splitting: Symmetric vs Asymmetric Vibrations
Identical bonds within a polyatomic group can stretch symmetrically (in-phase) or asymmetrically (out-of-phase). Similar to hydrogen bonding, these vibrations also influence the shape of the IR peak. Generally, asymmetric stretching frequencies are higher than symmetric stretching frequencies. For example, primary amines exhibit two distinct IR peaks between 3300–3500 cm−1 corresponding to the symmetric and asymmetric N-H stretching, while secondary amines exhibit a single stretching vibration...
01:14NMR Spectroscopy of Aromatic Compounds
Aromatic compounds can be identified or analyzed using proton NMR and carbon‐13 NMR. Typically, aromatic hydrogens or hydrogens directly bonded to the aromatic rings are strongly deshielded by the aromatic ring current. Therefore, they absorb in the range of 6.5–8.0 ppm in proton NMR spectra. For instance, aromatic hydrogens directly bonded to the benzene ring absorb at 7.3 ppm. However, aromatic hydrogens of larger rings absorb farther upfield or downfield than the ideal range. Consider...
01:29IR and UV–Vis Spectroscopy of Aldehydes and Ketones
Infrared spectroscopy, also known as vibrational spectroscopy, is mainly used to determine the types of bonds and functional groups in molecules. In aldehydes and ketones, the carbonyl (C=O) bond shows an absorption around 1710 cm-1. The C=O bond vibration of an aldehyde occurs at lower frequencies than that of a ketone. In addition to the C=O absorption in an aldehyde, the aldehydic C–H bond also gives two peaks in the 2700–2800 cm-1 range. This absorption, coupled with the C=O stretching, is...