Yulong Gong

Evaluating two new Schiff bases synthesized on the inhibition of corrosion of copper in NaCl solutions

Two kinds of new Schiff base derivatives, 2-((4-(4-(dimethylamino)styryl)phenylimino)methyl) (DSM) and its intermediate 4-(4-aminostyryl)-N,N-dimethylaniline (AND), form self-assembled monolayers (SAMs) on copper surfaces. The SAMs have been examined by a series of techniques, including contact angle (CA), atomic force microscope (AFM), scanning electronic microscope (SEM), and electrochemical measurements. The results suggest that the two derivatives adsorb onto the copper surface and generate corresponding hydrophobic films, which play an important role in the anticorrosion of copper in 3% NaCl solution. Quantum chemical calculations and molecular dynamics (MD) simulation are also used for further insight into the adsorption mechanism.

Systematic investigation of the synthesis and light-absorption broadening of a novel diketopyrrolopyrrole conjugated polymer of low and high molecular weight with thermo-labile groups

To strengthen the π–π stacking interaction of conjugated polymer chains and study the absorption broadening effect, a narrow band-gap copolymer with high (DPP-Car-Boc-H) and low (DPP-Car-Boc-L) molecular weight, comprising alkyl substituted diketopyrrolopyrrole (DPP) and t-butoxycarbonyl (t-Boc)-protected carbazole (Car-Boc) units, is designed and synthesized. The absorption broadening is investigated on the basis of molecular weight, solution and solid state, solution temperature and nonsolvent effect. FTIR analysis confirmed the decomposition of t-butoxycarbonyl protecting groups after thermal annealing treatment. It is found that the removal of thermo-labile groups (t-Boc) at 180 °C and the liberation of active NH groups further broaden the light-absorption spectra in thin films due to the intensified π–π stacking interaction between polymer chains which is verified through TGA, SEM and XRD. After thermal annealing, SEM images exhibited cubic crystals spread uniformly and the increased order degree of aggregation was verified further. Additionally, the impact of electronic structure change on the photo-response broadening effect is excluded by Gaussian molecular simulation. This work provides a viable approach and convincing evidence that thermal fabrication strengthens conjugated polymer chain stacking through the large π-delocalized plane and provides broad absorption properties for use in photoelectric devices.

A Successful Attempt to Obtain the Linear Dependence Between One-Photon and Two-Photon Spectral Properties and Hammett Parameters of Various Aromatic Substituents in New π-Extended Asymmetric Organic Chromophores

A series of new asymmetric chromophores containing aromatic substituents and possessing the excellent π-extension in space were prepared through multi-steps routes. One-photon and two-photon spectral properties of these new chromophores could be tuned by these substituents finely and simultaneously. The linear correlation of the wave numbers of the one-photon absorption and emission maxima to Hammett parameters of these substituents was presented. Near infrared two-photon absorption emission integrated areas of the target chromophores were correlated linearly to Hammett constants of these substituted groups.