Back to Search Start Over

Characterization of Excited-State Electronic Structure in Diblock π-Conjugated Oligomers with Adjustable Linker Electronic Coupling.

Authors :
Gobeze, Habtom B.
Younus, Muhammed
Turlington, Michael D.
Ahmed, Sohel
Schanze, Kirk S.
Source :
Molecules; Jun2024, Vol. 29 Issue 11, p2678, 14p
Publication Year :
2024

Abstract

Diblock conjugated oligomers are π-conjugated molecules that contain two segments having distinct frontier orbital energies and HOMO-LUMO gap offsets. These oligomers are of fundamental interest to understand how the distinct π-conjugated segments interact and modify their excited state properties. The current paper reports a study of two series of diblock oligomers that contain oligothiophene (T<subscript>n</subscript>) and 4,7-bis(2-thienyl)-2,1,3-benzothiadiazole (TBT) segments that are coupled by either ethynyl (-C≡C-) or trans-(-C≡C-)<subscript>2</subscript>Pt(II)(PBu<subscript>3</subscript>)<subscript>2</subscript> acetylide linkers. In these structures, the T<subscript>n</subscript> segment is electron rich (donor), and the TBT is electron poor (acceptor). The diblock oligomers are characterized by steady-state and time-resolved spectroscopy, including UV-visible absorption, fluorescence, fluorescence lifetimes, and ultrafast transient absorption spectroscopy. Studies are compared in several solvents of different polarity and with different excitation wavelengths. The results reveal that the (-C≡C-) linked oligomers feature a delocalized excited state that takes on a charge transfer (CT) character in more polar media. In the (-C≡C-)<subscript>2</subscript>Pt(II)(PBu<subscript>3</subscript>)<subscript>2</subscript>-linked oligomers, there is weak coupling between the T<subscript>n</subscript> and TBT segments. Consequently, short wavelength excitation selectively excites the T<subscript>n</subscript> segment, which then undergoes ultrafast energy transfer (~1 ps) to afford a TBT-localized excited state. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
14203049
Volume :
29
Issue :
11
Database :
Complementary Index
Journal :
Molecules
Publication Type :
Academic Journal
Accession number :
177861924
Full Text :
https://doi.org/10.3390/molecules29112678