Article
Acid/Base-Triggered Switching of Circularly Polarized Luminescence and Electronic Circular Dichroism in Organic and Organometallic Helicenes
Chemistry – A European Journal
(2015)
Abstract
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.
Disciplines
Publication Date
January 19, 2015
DOI
10.1002/chem.201405176
Citation Information
Nidal Saleh, Barry Moore, Monika Srebro, Nicolas Vanthuyne, et al.. "Acid/Base-Triggered Switching of Circularly Polarized Luminescence and Electronic Circular Dichroism in Organic and Organometallic Helicenes" Chemistry – A European Journal Vol. 21 Iss. 4 (2015) p. 1673 - 1681 ISSN: 1521-3765 Available at: http://works.bepress.com/gilles_muller/56/