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.
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 n class="Chemical">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.
Authors: Esther M Sánchez-Carnerero; Antonia R Agarrabeitia; Florencio Moreno; Beatriz L Maroto; Gilles Muller; María J Ortiz; Santiago de la Moya Journal: Chemistry Date: 2015-07-01 Impact factor: 5.236
Authors: Rua B Alnoman; Sandra Rihn; Daniel C O'Connor; Fiona A Black; Bernard Costello; Paul G Waddell; William Clegg; Robert D Peacock; Wouter Herrebout; Julian G Knight; Michael J Hall Journal: Chemistry Date: 2015-11-30 Impact factor: 5.236
Authors: I Hernández Delgado; S Pascal; A Wallabregue; R Duwald; C Besnard; L Guénée; C Nançoz; E Vauthey; R C Tovar; J L Lunkley; G Muller; J Lacour Journal: Chem Sci Date: 2016-04-08 Impact factor: 9.825