Single-step access to a series of D–A π-conjugated oligomers with 3–10 nm chain lengths

A series of five D–A π-conjugated oligo(DPP-co-fluorene)s progressively consisting of 3, 5, 7, 9 and 11 monomers and with chain lengths ranging between 3 and 10 nm have all been synthesized in a single step by direct C–H arylated coupling.

Computational calculation identified optimal binding sites in nano-sized magnetic-cored dendrimer

Magnetic-cored dendrimers (MDs) with amino groups were prepared with the formation of poly(amidoamine) dendrimer on the surface of magnetite nanoparticles (MNPs). The experiment involved the binding of four different heavy metal ions including Pb (II), Cu (II), Zn (II), and Cr (VI). Density functional theory (DFT) calculation was applied to the experimental results to determine the optimal configurations between the heavy metal species and generation 1 amino (NH₂) functionalized MD (G1-NH₂-MD). Different binding configurations among the possible binding positions of inner and outer G1-NH₂-MD were determined with the ionic radius and coordination number of each heavy metal ion. Although Pb²⁺ and Zn²⁺ were stable in the terminal positions, Cu²⁺ was the most stable in the internal position. The oxygen and hydrogen atoms of HCrO₄^- formed a hydrogen bond with the NH₂ groups, and thus dipole-nonpolar molecular interaction occurred with the CH₂ groups of G1-NH₂-MD. Specific binding positions and energies of different heavy metal species were identified through the DFT calculation in the study. The DFT calculation results also contributed to an understanding of the binding priority of each metal ions in the mixed solution. Furthermore, Pb²⁺ was preferably adsorbed in the mixed solution of Pb²⁺, Cu²⁺, and Zn²⁺.

Structure-property relationships and third-order nonlinearities in diketopyrrolopyrrole based D-π-A-π-D molecules

Nine new quadrupolar chromophores based on diketopyrrolopyrrole were designed and prepared by cross-coupling reactions. The property tuning has been achieved by structural variation of the peripheral substituents (donor) and enlargement of the π-system. Fundamental properties of target molecules were studied by differential scanning calorimetry, electrochemistry, and absorption and emission spectra. Nonlinear optical properties were studied by measuring the third harmonic generation. The experimental data were completed by quantum-chemical calculations and structure–property relationships were elucidated.