Publication details for Prof. J.A. Gareth WilliamsSaleh, S., Moore II, B., Srebro, M., Vanthuyne, N., Toupet, L., Williams, J. A. G., Roussel, C., Deol, K. K., Muller, G., Autschbach, J. & 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): 1673-1681.
- Publication type: Journal Article
- ISSN/ISBN: 0947-6539 (print), 1521-3765 (online)
- DOI: 10.1002/chem.201405176
- Keywords: Circular dichroism, Density functional calculations, Helicenes, Luminescence, Switches.
- Further publication details on publisher web site
- Durham Research Online (DRO) - may include full text
Author(s) from Durham
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.