Oligothiophene S,S-Dioxides. Synthesis and Electronic Properties in Relation to the Parent Oligothiophenes
摘要:
Oligothiophene S,S-dioxides from dimers to pentamers were obtained in good yields by reaction of mono- and dibrominated thiophene S,S-dioxides with the appropriate thienyl stannanes in the presence of Pd(AsPh3)(4) generated in situ. The reaction rate with brominated thiophene S,S-dioxides is greatly accelerated compared to that employing thienyl bromides to obtain the parent oligothiophenes. HF/6-31G* ab initio calculations on 2,2'-bithiophene and the corresponding mono- and bis-S,S-dioxides show that the functionalization of the thienyl sulfur to the S,S-dioxide does not affect the pi,pi* nature of the frontier orbitals, decreases the energy of the LUMO much more than that of the HOMO, increases the degree of planarity of the molecular skeleton, and leads to higher syn anti rotation barriers about the carbon-carbon bond.
We report a new series of indoline dyes with a donor–aromatic–acceptor (D–π–A) structure. D–π–A metal-free organic dyes with indoline–benzothiazole–rhodanine units were synthesized and their photovoltaic performances were evaluated. The photoelectric conversion efficiency (η) of the indoline–benzothiazole–rhodanine dye is 3.7%, while that of the indoline–thiophene–rhodanine dye is 0.9% under the same conditions. The incident photon-to-current conversion efficiencies (IPCEs) of these dyes are 60% and 25%, respectively, at 500 nm. To understand their electronic structures, the geometries of the dyes were optimized by density functional theory (DFT) calculations at the 6-31G(d) level using a B3LYP exchange-correlation functional. As a result, the localized highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) of the indoline–benzothiazole–rhodanine dye were obtained and were compared with those of the indoline–thiophene–rhodanine dye.
Oligothiophene S,S-dioxides from dimers to pentamers were obtained in good yields by reaction of mono- and dibrominated thiophene S,S-dioxides with the appropriate thienyl stannanes in the presence of Pd(AsPh3)(4) generated in situ. The reaction rate with brominated thiophene S,S-dioxides is greatly accelerated compared to that employing thienyl bromides to obtain the parent oligothiophenes. HF/6-31G* ab initio calculations on 2,2'-bithiophene and the corresponding mono- and bis-S,S-dioxides show that the functionalization of the thienyl sulfur to the S,S-dioxide does not affect the pi,pi* nature of the frontier orbitals, decreases the energy of the LUMO much more than that of the HOMO, increases the degree of planarity of the molecular skeleton, and leads to higher syn anti rotation barriers about the carbon-carbon bond.
Loft, Michael S.; Mowlem, Timothy J.; Widdowson, David A., Journal of the Chemical Society. Perkin transactions I, 1995, # 2, p. 97 - 104
作者:Loft, Michael S.、Mowlem, Timothy J.、Widdowson, David A.