Synthesis of new heteroaromatic nitrogen ligands: Pyrimido-[4″,5″:4′,5′]-thieno[3′,2′:4,5]thieno[3,2-d]pyrimidines and 1,2,3-triazine[4″,5″:4′,5′]thieno[3′,2′:4,5]thieno[3,2-d]-1,2,3-triazines

Covalently linked thieno[2,3-b]thiophene-fullerene dimers: synthesis and physical characterization

Thienothiophene (TT) has received great attention in the fields of electronics and optoelectronics. Here we report a synthesis and characterization of fullerene-donor-fullerene triads linked to thieno[2,3-b]thiophene as a donor. The photophysical and electrochemical properties of the new dumbbells were investigated using UV-vis spectroscopy, fluorescence spectroscopy, cyclic voltammetry, and square wave voltammetry. The results showed that both compounds have higher LUMO energy levels than PC61BM, indicating that they can be used in photovoltaic applications. Furthermore, the powder was structurally and morphologically characterized via X-ray diffraction (XRD) and scanning electron microscopy (SEM). The SEM revealed the morphological characterization of the two derivatives as globular and urchin-like supramolecular assemblies.

Synthesis of 2,5-asymmetrically substituted 3,4-diaminothieno[2,3-b]thiophenes by domino reaction

A convenient one pot synthesis of 2,5-asymmetrically substituted thieno[2,3-b]thiophenes is developed. The method is based on consecutive domino reactions (SN2 reaction → Thorpe-Ziegler reaction) using malononitrile and carbon disulfide as starting materials with the generation of potassium 2,2-dicyanoethene-1,1-bis(thiolate) in a solution. The high yield of the target thienothiophenes was achieved using the Ziegler dilution effect.