Issue 14, 1999
From the journal:

Physical Chemistry Chemical Physics

Proton exchange and isomerisation reactions of photochromic and reverse photochromic spiro-pyrans and their merocyanine forms

Jonathan Hobley,   Vincenzo Malatesta,   Roberto Millini,   Luciano Montanari,   Wallace O Neil Parker  and  Vincenzo Malatesta, Roberto Millini, Luciano Montanari, Wallace O Neil Parker, Jr  

Abstract

Photochromic 1′,3′,3′-trimethyl-6,8-dinitro-spiro- [2H-1-benzopyran-2,2-indoline], (6,8-dinitro BIPS) has been studied in different solvents using 1H-NMR techniques, UV/visible spectroscopy, X-ray diffraction and electrospray ionisation mass spectroscopy (ESI-MS). Molar decadic absorption coefficients for 6,8-dinitro BIPS were found to range between 35000–45000 d mol-1 cm-1. 1H–1H NOESY and 1H-NMR experiments have established that in solution the merocyanine form of 6,8-dinitro BIPS is in rapid exchange between the trans-trans-cis (TTC) and trans-trans-trans (TTT) isomers. The 3B proton on the central bridging double bond of spiro-pyran merocyanines is labile in organic solvents. The closed form of 6,8-dinitro BIPS enantiomerises about the spiro C(2) carbon at a rate of 18 s-1 at 300 K. The activation energy for this process was estimated to be 46 kJ mol-1 using dynamic NMR.

About
Cited by
Related
Download options Please wait...

Supplementary files

Article information

DOI
https://doi.org/10.1039/A902379H
Article type
Paper

Phys. Chem. Chem. Phys., 1999,1, 3259-3267

Permissions

Request permissions

Proton exchange and isomerisation reactions of photochromic and reverse photochromic spiro-pyrans and their merocyanine forms

J. Hobley, V. Malatesta, R. Millini, L. Montanari, W. O Neil Parker and V. M. R. M. L. M. W. O. N. P. J., Phys. Chem. Chem. Phys., 1999, 1, 3259 DOI: 10.1039/A902379H

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

Spotlight

Advertisements