5.2.4 A Zinc(II) Homoleptic Helicate for Largely Enhanced
Absorption and Luminescence Dissymmetry Factors
in the Near-Infrared Region
Although the extended π-conjugated structure is a straightforward method for
enhanced absorption and fluorescence properties in the near-infrared (NIR) region,
the degree of the redshift-trend by such an approach is quite limited in the case of
carbohelicenes. For example, [16]carbohelicene [48] demonstrates an absorption
maximum at ca. 430 nm (cf. 324 nm for [6]-helicene and 390 nm for [9]-helicenes)
Fig. 5.6 Schematic illustrations of (a) quinoxaline fused tetrathia[9]helicene derivatives (reprinted
with permission from Ref. [46] Copyright 2016 Wiley-VCH) and (b) tetrasulfone[9]helicene in this
study (reprinted with permission from Ref. [47] Copyright 2016 American Chemical Society)
108
T. Hasobe
Absorption and Luminescence Dissymmetry Factors
in the Near-Infrared Region
Although the extended π-conjugated structure is a straightforward method for
enhanced absorption and fluorescence properties in the near-infrared (NIR) region,
the degree of the redshift-trend by such an approach is quite limited in the case of
carbohelicenes. For example, [16]carbohelicene [48] demonstrates an absorption
maximum at ca. 430 nm (cf. 324 nm for [6]-helicene and 390 nm for [9]-helicenes)
Fig. 5.6 Schematic illustrations of (a) quinoxaline fused tetrathia[9]helicene derivatives (reprinted
with permission from Ref. [46] Copyright 2016 Wiley-VCH) and (b) tetrasulfone[9]helicene in this
study (reprinted with permission from Ref. [47] Copyright 2016 American Chemical Society)
108
T. Hasobe