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A series of donor–acceptor ferrocenyl substituted bisthiazoles 3–8 were designed and synthesized by the Pd-catalyzed Suzuki, Heck, and Sonogashira cross-coupling reactions. Their photophysical, electrochemical and computational studies reveal strong donor–acceptor interactions. The photonic and electrochemical studies show that the ferrocenyl bisthiazoles with vinyl linkage ferrocenyl-bisthiazole 4, show better electronic communication compared to rest of the ferrocenyl bisthiazoles. The time dependent density functional theory (TD-DFT) calculation at B3LYP on the ferrocenyl substituted bisthiazoles 3–5 was performed, in which the ferrocenyl-bisthiazole 4 shows strong donor–acceptor interactions compared to the Fc-bisthiazoles 3 and 5. The thermal stability of the ferrocenyl substituted bisthiazoles 3–8 is reported, in which Fc-bisthiazole 8 shows high thermal stability. The single crystal structures of ferrocenyl-bisthiazoles 3 and 5 are reported. [ABSTRACT FROM AUTHOR]

A set of carbazole substituted BODIPYs 2a-2c were designed and synthesized by the Pd-catalysed Sonogashira cross-coupling reaction. The effects of variation in the donor strength of various carbazoles were investigated by photophysical, electrochemical and computational studies. The electronic absorption spectra of BODIPYs 2a and 2c show charge transfer bands, which show red shift in polar solvents. The BODIPYs 2a-2c are highly fluorescent in nonpolar solvents (emission from the localized state) and poorly fluorescent in polar solvents (emission from the charge transfer state). The photophysical and electrochemical studies reveal strong donor-acceptor interaction between carbazole and BODIPY and follows the order 2a > 2c > 2b. The computational calculations show good agreement with the experimental results. The single crystal structures of BODIPYs 2a-2c are reported, which exhibit interesting supramolecular interactions. The packing diagrams of 2a show a zigzag 3D structural arrangement, whereas 2b and 2c show complex 3D structural motifs. [ABSTRACT FROM AUTHOR]

A family of unsymmetrical donor-acceptor, ferrocenyl-substituted benzothiadiazoles of types D1-π-A-π-D2, D1-π-A1-π-A2, D1-A-π-D2, and D1-A1-A2-D2, bearing a variety of electron-donating and electron-withdrawing groups, were designed and synthesized. Their photophysical, electrochemical, and computational properties were explored, which show strong donor-acceptor interaction. The presence of electron-rich units anthracene (6f) and triphenylamine (6h), and an electron-deficient unit 1,1,4,4-tetracyanobuta-1,3-diene (TCBD) (9b) results in lowering of the band gap, which leads to a red shift of the absorption spectrum in these benzothiadiazole systems. The single crystal structures of 6c, 6g, 7a, and 7b are reported, which show marvelous supramolecular interactions. [ABSTRACT FROM AUTHOR]