Fine Tuning of the Electronic Properties of Linear π-Conjugated Oligomers by Covalent Bridging

An attempt to synthesize a terthienyl-based analog of indacenedithiophene (IDT): unexpected synthesis of a naphtho[2,3-b]thiophene derivative

We report herein our attempt to synthesize an analog of indacenedithiophene (IDT) based on a tetraphenylhexyl substituted, covalently bridged syn-terthienyl unit. Instead of the expected compound the adopted synthetic route led to the formation of an unexpected, new naphtho[2,3-b]thiophene derivative. The structure of this compound was fully characterized by NMR and HRMS as well as single crystal X-ray diffraction and its electronic properties have been analyzed by UV-vis absorption spectroscopy and cyclic voltammetry. A possible mechanism for the formation of this compound is also proposed on the basis of detailed theoretical investigations.

Serendipitous synthesis of a novel naphtho[2,3-b]thiophene derivative. Detailed investigation of the structure and properties as well as a possible mechanism for its formation.

Computational study on optoelectronic and charge transport properties of diketopyrrolopyrrole-based A-D-A-D-A structure molecules for organic solar cells

Eight novel diketopyrrolopyrrole (DPP)-based A-D-A-D-A structure molecules were designed for organic solar cells (OSCs) applications. In these molecules, the electron-deficient DPP and dicyanovinyl groups were used as the acceptor groups and different planar electron-rich groups were employed as the donor π-bridges. Applying the B3LYP/6-31G (d,p) and TD-B3LYP/6-31G (d,p) methods, the optoelectronic and charge transport properties were investigated. It turned out that the different π-bridges can tune effectively the frontier molecular orbital energy levels, band gap, and absorption spectra. Furthermore, the different π-bridges also affect the charge transport properties of the designed molecules. Our results suggest that the investigated molecules can serve as donor materials. Additionally, some investigated molecules can also be used as hole and/or electron transport materials for OSCs. Graphical abstract A series of novel A-D-A-D-A molecules are investigated systematically. The optical and electronic properties can be tuned effectively by the π-bridges. All derivatives can be used as donor materials for OSCs. Some designed molecules can be used as hole and/or electron transport materials. The different π-bridges do not significantly affect the stability of the molecules.

4,5-Dihydro-cyclo-penta-[b]thio-phen-6-one

The title compound, C(7)H(6)OS, crystallizes with two similar mol-ecules, 1 and 2, in the asymmetric unit. Both mol-ecules are essentially planar with r.m.s. deviations of 0.0193 and 0.0107 Å for the planes through the nine non-H atoms of mol-ecules 1 and 2, respectively. The thio-phene and 4,5-dihydro-cyclo-penta-dienone rings are inclined at 2.40 (13)° in 1 and 0.64 (13)° in 2. In the crystal structure π-π [3.6542 (17) Å] and C-H⋯π contacts stack the mol-ecules into columns in an inverse fashion along the b axis. An extensive series of C-H⋯O hydrogen bonds links the columns, generating an extended network structure.

Spectral and Photophysical Characterization of Donor-π-Acceptor Arylthienyl- and Bithienyl-Benzothiazole Derivatives in Solution and Solid State

A comprehensive study has been made in solution at room temperature (293 K), low temperature (77 K), and in thin films (Zeonex matrixes) of the spectral and photophysical properties of six arylthienyl- and bithienyl-benzothiazole derivatives functionalized with different donor groups. Similar experiments have been carried out with two related precursors (containing the arylthienyl and aryl-bithienyl conjugated systems), and results are compared. Singlet-singlet and triplet-triplet absorption spectra, emission spectra together with lifetimes and quantum yields have been obtained, and from these data the rates for all the radiative and nonradiative processes determined, providing information on the dominant decay processes. The arylthienyl-benzothiazole derivatives show high fluorescence quantum yields (phi(F)) with negligible internal conversion (phi(IC)), whereas the bithienyl-benzothiazoles display lower but still significant phi(F) values, but now radiationless processes (phi(IC) and phi(ISC)) are competitive. A comparison with the analogous oligothiophenes is made. Singlet oxygen yields were also determined and the triplet energy transfer to (3)O2 to produce (1)O2 was found to be highly efficient with values of S(Delta)(= phi(Delta)/phi(T)) varying from 0.4 to 1.

Communication in Platinum Ethynylchalcogenophenes

A series of alkynylchalcogenophene platinum(II) complexes have been synthesized and characterized by multinuclear NMR and UV-visible absorption spectroscopies; the NMR spectra show unprecedented long-range heteronuclear coupling, and clear correlations emerge between spectroscopic data and theoretical analysis of their electronic structures.