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Thiophene- and bithiophene-based π-conjugated Schiff base oligomers containing binaphthalene moieties in the backbone. Properties and computational simulations
Ist Teil von
Polymer chemistry, 2024-02, Vol.15 (7), p.639-651
Ort / Verlag
Cambridge: Royal Society of Chemistry
Erscheinungsjahr
2024
Link zum Volltext
Quelle
Alma/SFX Local Collection
Beschreibungen/Notizen
New π-conjugated Schiff base oligomers (
o-AZdAN1Th
and
o-AZdAN2Th
) based on a binaphthalene core and containing thiophene or bithiophene units in their backbone were synthesized from the reaction between [1,1′-binaphthalene]-4,4′-diamine with thiophene-2,5-dicarbaldehyde and [2,2′-bithiophene]-5,5′-dicarbaldehyde by a high-temperature polycondensation method. These new materials were slightly soluble in non-protic polar solvents, such as chloroform and dichloromethane. From GPC analysis of the CHCl
3
-soluble fraction,
o-AZdAN1Th
was found to be a tetramer, whereas
o-AZdAN2Th
was a trimer with 1.4 kDa and 1.3 kDa average molecular weight (
M
n
), respectively. Both samples exhibited high thermal stability with
T
5%
values of 452 °C and 456 °C and relatively high
T
g
values of 346 °C and 384 °C, for
o-AZdAN1Th
and
o-AZdAN2Th
, respectively. The samples showed absorptions in the deep-blue (
o-AZdAN1Th
) and blue (
o-AZdAN2Th
) regions of the visible spectrum, and emission responses at 387 nm and 447 nm, respectively, with moderate Stokes shifts (77-95 nm). Their optical and electronic properties were similar to those described for thiophene-based materials, with optical bandgap values close to 2.4 eV. HOMO energy values of −5.98 and −5.95 eV and LUMO energy values of −3.87 eV and −3.84 eV were obtained for
o-AZdAN1Th
and
o-AZdAN2Th
, respectively. Theoretical DFT and TD-DFT calculations were used to compare the effect of increasing thiophene units along the backbone for the real and also theoretical
o-AZdAN
x
Th
samples (
x
= 3 and 4 thiophene units). According to our study, these two new thiophene-based can be proposed for optoelectronic applications.
Schiff base oligomers based on a binaphthalene core were synthesized from [1,1′-binaphthalene]-4,4′-diamine with thiophene-2,5-dicarbaldehyde and [2,2′-bithiophene]-5,5′-dicarbaldehyde by a high-temperature polycondensation method.