Jump to main content
Jump to site search
SCHEDULED MAINTENANCE Close the message box

Maintenance work is planned for Monday 16 August 2021 from 07:00 to 23:59 (BST).

Website performance may be temporarily affected and you may not be able to access some PDFs or images. If this does happen, refreshing your web browser should resolve the issue. We apologise for any inconvenience this might cause and thank you for your patience.


Issue 16, 2018

Ultrafast stimulated emission of nitrophenolates in organic and aqueous solutions

Author affiliations

Abstract

Early-time dynamics of nitroaromatics and its coressponding bases can give valuable insights into photo-induced reactions relevant to atmospheric and environmental processes. In this work, femtosecond broadband absorption spectroscopy between 350 and 700 nm has been applied to explore the ultrafast dynamics of o-, p- and m-nitrophenol anions (NP) in basic organic and aqueous solution. Excitation at 400 nm promotes these compounds into the first bright electronic singlet state, which is a charge-transfer state. A surprising finding for all nitrophenolates was a characteristic, spectrally broad stimulated emission (SE) from the electronically excited state into the ground state. The corresponding lifetime was on the order of a few hundred femtoseconds for o- and p-NP while it was roughly ten times larger for m-NP. In line with earlier observations, the SE is governed by an out-of-plane torsional motion of the nitro group, leading to a close energetic approach of the relevant electronically excited singlet and ground states. Subsequent dynamics can be assigned to excited state absorption and ground state relaxation due to energy dissipation of the vibrational modes to the solvent that occur for up to several tens of picoseconds. No longer-lasting transient absorption (TA) was found; instead, a complete recovery of the ground state bleaching was observed indicating that triplet state relaxation is either not significantly involved in this spectral part or shifted to other regions. In the aqueous system, time constants for all processes are much smaller than in organic solution, a fact that can be explained by the larger dipole moment of the solvent and the correspondingly stronger intermolecular coupling between NP and the aqueous solvent.

Graphical abstract: Ultrafast stimulated emission of nitrophenolates in organic and aqueous solutions

Supplementary files

Article information


Submitted
17 Nov 2017
Accepted
10 Jan 2018
First published
10 Jan 2018

Phys. Chem. Chem. Phys., 2018,20, 10713-10720
Article type
Paper

Ultrafast stimulated emission of nitrophenolates in organic and aqueous solutions

N. C. Michenfelder, H. A. Ernst, C. Schweigert, M. Olzmann and A.-N. Unterreiner, Phys. Chem. Chem. Phys., 2018, 20, 10713 DOI: 10.1039/C7CP07774B

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.


Social activity

Search articles by author

Spotlight

Advertisements