Circularly Polarized Thermally Activated Delayed Fluorescence molecules in the
rest of the document) [13]. This first approach toward such molecules was based on
the construction of a chiral carbon center bearing an electron donor, a triarylamine
unit, and an acceptor unit, naphthacen-5(12H)-one (see Fig. 13.2).
The target molecule, 12-(2-(diphenylamino)phenyl)-12-hydroxynaphthacen-5
(12H)-one (DPHN), was obtained by the addition of the 2-litiumtriphenylamine,
prepared by a classical halogen-lithium exchange on the 2-bromotriphenylamine A,
to the 5,12-naphthacenequinone B using THF as solvent giving the target compound
in 47% yield (see Scheme 13.1). Thereafter, the two enantiomers of the racemic
mixture were separated using preparative chiral high-pressure liquid chromatography (HPLC).
Both enantiomers of compound 1 display green emission in toluene solution
with a maximum wavelength centered on 513 nm. DFT and TD-DFT calculations at
the B3LYP/6-31G(d,p) level have revealed some interesting insight concerning the
photophysical properties of this molecule which can be resumed as follows: at the
fundamental state (S 0 ), the transition that generates the first absorption band showed
a weak charge transfer (CT) character with rather high spatial separation of the
HOMO and LUMO. At the lowest singlet state (S 1 ), the character of the HOMOLUMO transition was pure CT with a better spatial separation of the HOMO (located
predominantly on triarylamine substructure) and LUMO (mainly located on the
acceptor unit) compared to the S 0 state. The calculated energy difference between
the lowest singlet state (S 1 ) and the lowest triplet state (T 1 ), ΔE ST, was found to be
Fig. 13.2 Design of CPTADF molecules reported by Hirata et al
O
OH
N
N
Br
O
O
1) n-BuLi, THF
2)
1
Racemate
Separation using chiral HPLC
A
B
Scheme 13.1 Synthesis of the 12-(2-(diphenylamino)phenyl)-12-hydroxynaphthacen-5(12H)-one
296
G. Pieters and L. Frederic
rest of the document) [13]. This first approach toward such molecules was based on
the construction of a chiral carbon center bearing an electron donor, a triarylamine
unit, and an acceptor unit, naphthacen-5(12H)-one (see Fig. 13.2).
The target molecule, 12-(2-(diphenylamino)phenyl)-12-hydroxynaphthacen-5
(12H)-one (DPHN), was obtained by the addition of the 2-litiumtriphenylamine,
prepared by a classical halogen-lithium exchange on the 2-bromotriphenylamine A,
to the 5,12-naphthacenequinone B using THF as solvent giving the target compound
in 47% yield (see Scheme 13.1). Thereafter, the two enantiomers of the racemic
mixture were separated using preparative chiral high-pressure liquid chromatography (HPLC).
Both enantiomers of compound 1 display green emission in toluene solution
with a maximum wavelength centered on 513 nm. DFT and TD-DFT calculations at
the B3LYP/6-31G(d,p) level have revealed some interesting insight concerning the
photophysical properties of this molecule which can be resumed as follows: at the
fundamental state (S 0 ), the transition that generates the first absorption band showed
a weak charge transfer (CT) character with rather high spatial separation of the
HOMO and LUMO. At the lowest singlet state (S 1 ), the character of the HOMOLUMO transition was pure CT with a better spatial separation of the HOMO (located
predominantly on triarylamine substructure) and LUMO (mainly located on the
acceptor unit) compared to the S 0 state. The calculated energy difference between
the lowest singlet state (S 1 ) and the lowest triplet state (T 1 ), ΔE ST, was found to be
Fig. 13.2 Design of CPTADF molecules reported by Hirata et al
O
OH
N
N
Br
O
O
1) n-BuLi, THF
2)
1
Racemate
Separation using chiral HPLC
A
B
Scheme 13.1 Synthesis of the 12-(2-(diphenylamino)phenyl)-12-hydroxynaphthacen-5(12H)-one
296
G. Pieters and L. Frederic