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: 16Citation - Scopus: 19N,n-Dialkylaniline Tetraethynylethenes: a New Class of Chromophores Possessing an Emitting Charge-Transfer State. Experimental and Computational Studies(John Wiley and Sons Inc., 2001) Gobbi, Luca; Elmacı, Nuran; Lüthi, Hans Peter; Diederich, FrançoisThe photophysical properties of N,N-dimethylaniline- (DMA) substituted tetraethynylethene (TEE; 3,4-diethynylhex-3-ene-1,5-diyne) and related derivatives were investigated in a joint experimental and computational study. Measurements of the electronic emission spectra showed that these novel chromophores display a dual fluorescence which strongly depends on solvent polarity. Computational studies suggest that the twisted intramolecular charge-transfer state (TICT) model offers a possible explanation for the experimentally observed dual fluorescence. Time-dependent density functional calculations revealed that the initial excited state reached upon photoirradiation relaxes to a lower-energy TICT state in which either the dimethylamino group is twisted into an orthogonal position with respect to the remaining planar arylated TEE moiety or the entire DMA donor group takes an orthogonal orientation with respect to the rigid, planar TEE acceptor moiety. For the compounds investigated, the charge-transfer state responsible for the strongly solvent-dependent luminescence is directly connected with the initial excited state, namely, no crossing of states is involved.