Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - WoS: 5Citation - Scopus: 6Donor- And/Or Acceptor-Substituted Expanded Radialenes: Theory, Synthesis, and Properties(American Chemical Society, 2014) Ramsaywack, Sharwatie; Karaca, Sıla; Gholami, Mojtaba; Murray, Adrian H.; Hampel, Frank; McDonald, Robert; Elmacı, Nuran; Lüthi, Hans Peter; Tykwinski, Rik R.The synthesis of donor- (D) and/or acceptor (A)-expanded [4]radialenes has been developed on the basis of readily available dibromoolefin (7), tetraethynylethene (10 and 20), and vinyl triflate (12) building blocks. The successful formation of D/A radialenes relies especially on (1) effective use of a series alkynyl protecting groups, (2) Sonogashira cross-coupling reactions, and (3) the development of ring closing reactions to form the desired macrocyclic products. The expanded [4]radialene products have been investigated by spectroscopic (UV-vis absorption and emission) and quantum chemical computational methods (density functional theory and time dependent DFT). The combined use of theory and experiment provides a basis to evaluate the extent of D/A interactions via the cross-conjugated radialene framework as well as an interpretation of the origin of D/A interactions at an orbital level.Article Citation - WoS: 13Citation - Scopus: 16Thermochromism in Oligothiophenes: the Role of the Internal Rotation(American Chemical Society, 2002) Elmacı, Nuran; Yurtsever, ErsinThe relation between thermochromism in polythiophenes and the internal rotation is studied by density-functional theory (DFT). For head-to-tail methyl-substituted thiophenes, rotational potential maps of dimer and trimer are calculated. With time-dependent-DFT methodology the absorption spectra of these oligomers in UV-vis region are calculated as functions of the torsional angles. Theoretical temperature-dependent UV-vis spectra are generated from the distribution of torsional angles. The results show that the internal rotation alone is not sufficient to explain the mechanism of thermochromism.