1,4-Bis(4-nitro-styr-yl)benzene

Comparison of 1,4-distyrylfluorene and 1,4-distyrylbenzene analogues: synthesis, structure, electrochemistry and photophysics

A series of nine 1,4-distyrylfluorene derivatives (2) functionalized with substituents of variable electrondonating or -accepting capabilities was synthesised. The photophysical properties of the molecules were investigated, including UV/vis absorption, photoluminescence emission, and fluorescence quantum yields. Photophysical properties of chromophores 2 were found to exhibit significant solvatochromic effects, especially in the Stokes shift and photoluminescence maxima. The electrochemical properties of series 2 were also assessed by cyclic voltammetry and differential pulse voltammetry. Results of photophysical and electrochemical analyses were further supported by DFT calculations (B3LYP/6-31G*) and single crystal X-ray diffraction on select molecules. The contributions of intermolecular π-stacking and hydrogen bonding to crystal packing are discussed. A series of nine 1,4-distyrylphenylene derivatives (3) were also synthesised and similarly characterized for comparison to photophysical and solvatochromic effects observed in series 2. Properties of similarly-substituted molecules in series 2 and 3 were compared to one another in order to assess the influence of the 1,4-fluorenylene unit.

4-[(1E,3E,5E)-6-(4-Pyrid-yl)hexa-1,3,5-trien-yl]pyridine

The two independent mol-ecules in the asymmetric unit of the title compound, C(16)H(14)N(2), are planar [dihedral angle between the terminal pyridine rings = 1.76 (2)°] and each display an all-trans configuration of C=C double bonds. One of the two mol-ecules lies about a center of inversion. The dihedral angle between the two pyridine rings in the mol-ecule lying on a general position is 1.65 (2)°.