Time-resolved study of the photochemical reaction of 4-dimethylaminobenzonitrile with carbon tetrachloride

doi:10.1002/JRS.679

Paper

Time-resolved study of the photochemical reaction of 4-dimethylaminobenzonitrile with carbon tetrachloride

Published Feb 1, 2001 · Chensheng Ma, W. Kwok, P. Matousek

Journal of Raman Spectroscopy

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Abstract

The mechanism of 4-dimethylaminobenzonitrile (DMABN) fluorescence quenching by carbon tetrachloride was studied using time-resolved fluorescence, absorption and Raman techniques. Picosecond and nanosecond time-resolved Raman spectra of DMABN and DMABN-d6 were obtained in resonance with different electronic states to identify intermediates, their structure and time-dependent dynamic changes. The quenching is attributed to intermolecular electron transfer between B-state DMABN and carbon tetrachloride with a time constant of ∼500 fs leading to the formation of the DMABN radical cation as the initial intermediate followed by a ∼13 ps process yielding a DMABN Cl adduct as product with a lifetime longer than 50 ns. It is likely that the chlorine atom is located at the amino para-ring position of the highly reactive DMABN radical cation. It is suggested that this reaction mechanism is general for other donor–aromatic–acceptor type DMABN derivatives. Copyright © 2001 John Wiley & Sons, Ltd.

Study Snapshot

The quenching of 4-dimethylaminobenzonitrile fluorescence by carbon tetrachloride is attributed to intermolecular electron transfer, with a general reaction mechanism for other donor-aromatic-acceptor type DMABN derivatives.

PopulationOlder adults (50-71 years)

Sample size24

MethodsObservational

OutcomesBody Mass Index projections

ResultsSocial networks mitigate obesity in older groups.

Paper

Time-resolved study of the photochemical reaction of 4-dimethylaminobenzonitrile with carbon tetrachloride

References

Infrared and Raman spectra of 4-(dimethylamino)benzonitrile and isotopomers in the ground state and vibrational analysis

The strong interaction between the dimethylamino group and the benzene ring is directly reflected in the force field of 4-(dimethylamino)benzonitrile (DMABN).

Time-resolved resonance Raman spectra of the intramolecular charge transfer state of DMABN

Picosecond time-resolved Raman spectra reveal new resonance Raman bands in the 750-2200 cm 1 region, supporting the TICT model.

Picosecond Time-Resolved Study of 4-Dimethylaminobenzonitrile in Polar and Nonpolar Solvents

Picosecond time-resolved resonance Raman spectroscopy reveals the geometric and electronic structural changes in 4-dimethylaminobenzonitrile in polar and nonpolar solvents.

The PICT model for dual fluorescence of aminobenzonitriles.

The PICT model for dual fluorescence of aminobenzonitriles is not valid for 4-(dimethylamino)benzonitrile, 3-(dimethylamino)benzonitrile, and two dicyano-N,N-dimethylanilines due to their large energy gap

Fluorescence quenching dynamics of azulene and 2-haloazulenes by CCl4 in nonpolar solvents

Azulene fluorescence is efficiently quenched by carbon tetrachloride, while 2-haloazulenes show no fluorescence quenching by CCl4 in nonpolar solvents.

Do twisting and pyramidalization contribute to the reaction coordinate of charge-transfer formation in DMABN and derivatives?

Both twisting and anti-pyramidalization contribute to the charge-transfer formation in DMABN and derivatives, explaining the emission properties of the CT state.

Efficient Rejection of Fluorescence from Raman Spectra Using Picosecond Kerr Gating

The Kerr gate-driven method effectively rejects fluorescence from Raman spectra, achieving the highest time resolution achieved experimentally for fluorescence rejection in spectroscopy.

Excited state structure of 4-(dimethylamino)benzonitrile studied by femtosecond mid-infrared spectroscopy and ab initio calculations

Femtosecond mid-infrared spectroscopy and ab initio calculations reveal that 4-(dimethylamino)benzonitrile's excited-state structure is highly sensitive to changes in substituents, with a 4.0 ps charge-transfer time resolved for the first time.

Time-resolved spectroscopy of DMABN and its cage derivatives 6-cyanobenzquinuclidine (CBQ) and benzquinuclidine (BQ)

Picosecond transient absorption spectra of DMABN and CBQ in acetonitrile support the intramolecular charge transfer character of the relaxed singlet excited state in polar solvents.

Citations

Absorption and fluorescence solvatochromic behaviors of centrosymmetric D-π-D molecules with TTF/dimethylamino electron donors and polyenic π-bridge

TTF-CH=CH-CH=CH-CH-TTF exhibits negative solvatochromism due to quadrupole-dipole electrostatic interaction, while Me 2 NPh-CH=CH-CH=CH-CH-PhNMe 2 exhibits positive solvatochromis

Photophysics and photodeprotection reactions of p-methoxyphenacyl phototriggers: an ultrafast and nanosecond time-resolved spectroscopic and density functional theory study.

The (3)npi/pipi mixed character triplet of p-methoxyphenacyl phototriggers influences the formation of photoproducts, with a faster deprotection reaction in H(2)O/CH(3)CN and fluorinated alcohols.

Resonance Raman study of ring deuterated 4-dimethylaminobenzonitrile (DMABN-d4): the ground, ICT and triplet states

Ring deuterated 4-dimethylaminobenzonitrile (DMABN-d4) reveals a clearer planar structure and full localization of negative charge on the cyano group, confirming previous results.

Time-resolved study of the photochemical reaction of 4-dimethylaminobenzonitrile with carbon tetrachloride

References

Infrared and Raman spectra of 4-(dimethylamino)benzonitrile and isotopomers in the ground state and vibrational analysis

The strong interaction between the dimethylamino group and the benzene ring is directly reflected in the force field of 4-(dimethylamino)benzonitrile (DMABN).

Time-resolved resonance Raman spectra of the intramolecular charge transfer state of DMABN

Picosecond time-resolved Raman spectra reveal new resonance Raman bands in the 750-2200 cm 1 region, supporting the TICT model.

Picosecond Time-Resolved Study of 4-Dimethylaminobenzonitrile in Polar and Nonpolar Solvents

Picosecond time-resolved resonance Raman spectroscopy reveals the geometric and electronic structural changes in 4-dimethylaminobenzonitrile in polar and nonpolar solvents.

The PICT model for dual fluorescence of aminobenzonitriles.

The PICT model for dual fluorescence of aminobenzonitriles is not valid for 4-(dimethylamino)benzonitrile, 3-(dimethylamino)benzonitrile, and two dicyano-N,N-dimethylanilines due to their large energy gap

Fluorescence quenching dynamics of azulene and 2-haloazulenes by CCl4 in nonpolar solvents

Azulene fluorescence is efficiently quenched by carbon tetrachloride, while 2-haloazulenes show no fluorescence quenching by CCl4 in nonpolar solvents.

Do twisting and pyramidalization contribute to the reaction coordinate of charge-transfer formation in DMABN and derivatives?

Both twisting and anti-pyramidalization contribute to the charge-transfer formation in DMABN and derivatives, explaining the emission properties of the CT state.

Efficient Rejection of Fluorescence from Raman Spectra Using Picosecond Kerr Gating

The Kerr gate-driven method effectively rejects fluorescence from Raman spectra, achieving the highest time resolution achieved experimentally for fluorescence rejection in spectroscopy.

Excited state structure of 4-(dimethylamino)benzonitrile studied by femtosecond mid-infrared spectroscopy and ab initio calculations

Femtosecond mid-infrared spectroscopy and ab initio calculations reveal that 4-(dimethylamino)benzonitrile's excited-state structure is highly sensitive to changes in substituents, with a 4.0 ps charge-transfer time resolved for the first time.

Time-resolved spectroscopy of DMABN and its cage derivatives 6-cyanobenzquinuclidine (CBQ) and benzquinuclidine (BQ)

Picosecond transient absorption spectra of DMABN and CBQ in acetonitrile support the intramolecular charge transfer character of the relaxed singlet excited state in polar solvents.

Citations

Absorption and fluorescence solvatochromic behaviors of centrosymmetric D-π-D molecules with TTF/dimethylamino electron donors and polyenic π-bridge

TTF-CH=CH-CH=CH-CH-TTF exhibits negative solvatochromism due to quadrupole-dipole electrostatic interaction, while Me 2 NPh-CH=CH-CH=CH-CH-PhNMe 2 exhibits positive solvatochromis

Photophysics and photodeprotection reactions of p-methoxyphenacyl phototriggers: an ultrafast and nanosecond time-resolved spectroscopic and density functional theory study.

The (3)npi*/pipi* mixed character triplet of p-methoxyphenacyl phototriggers influences the formation of photoproducts, with a faster deprotection reaction in H(2)O/CH(3)CN and fluorinated alcohols.

Resonance Raman study of ring deuterated 4-dimethylaminobenzonitrile (DMABN-d4): the ground, ICT and triplet states

Ring deuterated 4-dimethylaminobenzonitrile (DMABN-d4) reveals a clearer planar structure and full localization of negative charge on the cyano group, confirming previous results.

The (3)npi/pipi mixed character triplet of p-methoxyphenacyl phototriggers influences the formation of photoproducts, with a faster deprotection reaction in H(2)O/CH(3)CN and fluorinated alcohols.