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Acid/base-triggered switching of circularly polarized luminescence and electronic circular dichroism in organic and organometallic helicenes.

Saleh, S. and Moore II, B. and Srebro, M. and Vanthuyne, N. and Toupet, L. and Williams, J. A. G. and Roussel, C. and Deol, K. K. and Muller, G. and Autschbach, J. and Crassous, C. (2015) 'Acid/base-triggered switching of circularly polarized luminescence and electronic circular dichroism in organic and organometallic helicenes.', Chemistry : a European journal., 21 (4). pp. 1673-1681.


Electronic circular dichroism and circularly polarized luminescence acid/base switching activity has been demonstrated in helicene-bipyridine proligand 1 a and in its “rollover” cycloplatinated derivative 2 a. Whereas proligand 1 a displays a strong bathochromic shift (>160 nm) of the nonpolarized and circularly polarized luminescence upon protonation, complex 2 a displays slightly stronger emission. This strikingly different behavior between singlet emission in the organic helicene and triplet emission in the organometallic derivative has been rationalized by using quantum-chemical calculations. The very large bathochromic shift of the emission observed upon protonation of azahelicene-bipyridine 1 a has been attributed to the decrease in aromaticity (promoting a charge-transfer-type transition rather than a π–π* transition) as well as an increase in the HOMO–LUMO character of the transition and stabilization of the LUMO level upon protonation.

Item Type:Article
Keywords:Circular dichroism, Density functional calculations, Helicenes, Luminescence, Switches.
Full text:(AM) Accepted Manuscript
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Publisher statement:This is the peer reviewed version of the following article: Saleh, N., Moore, B., Srebro, M., Vanthuyne, N., Toupet, L., Williams, J. A. G., Roussel, C., Deol, K. K., Muller, G., Autschbach, J. and Crassous, J. (2014), Acid/Base-Triggered Switching of Circularly Polarized Luminescence and Electronic Circular Dichroism in Organic and Organometallic Helicenes. Chemistry - a European journal, 21 (4): 1673-1681, which has been published in final form at This article may be used for non-commercial purposes in accordance With Wiley-VCH Terms and Conditions for self-archiving.
Date accepted:No date available
Date deposited:21 November 2014
Date of first online publication:21 November 2014
Date first made open access:No date available

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