Isomerically Pure Oxindole-Terminated Quinoids for n-Type Organic Thin-Film Transistors Enabled by the Chlorination of Quinoidal Core.

Quinoidal compounds have great potential utility as high-performance organic semiconducting materials because of their rigid planar structures and extended π-conjugation. However, the existence of E and Z isomers adversely affects the charge-transport properties of quinoidal compounds. In this study, three isomerically pure oxindole-terminated quinoids were developed by introducing chlorine atoms in the quinoidal core. The synthesized quinoids were confirmed to have a Z,Z configuration by means of 1 H NMR spectroscopy, density functional theory calculations, and single-crystal X-ray analysis. Importantly, the strategy of chlorination allowed to maintain low-lying frontier molecular orbital energy levels and ensure favorable intermolecular packing. Consequently, all three quinoidal compounds showed n-type transport characteristics in organic thin-film transistors, with electron mobilities up to 0.35 cm2 V-1 s-1 , which is the highest value reported to date for oxindole-terminated quinoids. Our study can provide new guidelines for the design of isomerically pure quinoids with high electron mobilities.

Self-Doped n-Type Quinoidal Compounds with Good Air Stability and High Electrical Conductivity for Organic Electronics.

Air stable n-type conductive molecules with high electrical conductivities and excellent device performance have important applications in organic electronics, but their synthesis remains challenging. Herein, we report three self-doped n-type conductive molecules, designated QnNs, with a closed-shell quinoidal backbone and alkyl amino chains of different lengths. The QnNs are self-doped by intermolecular electron transfer from the amino groups to the quinoidal backbone. This process is ascertained unambiguously by experiments and theoretical calculations. The use of a quinoidal structure effectively improves the self-doping level, and thus increases the electrical conductivity of self-doped n-type conductive molecules achieved by a closed-shell structure from<10-4  S cm-1 to>0.03 S cm-1 . Furthermore, the closed-shell quinoidal structure results in good air stability of the QnNs, with half-lives>73 days; and Q4N shows an electrical conductivity of 0.019 S cm-1 even after exposure to air for 120 days. When applying Q6N as the cathode interlayer in organic solar cells (OSCs), an outstanding power conversion efficiency of up to 18.2 % was obtained, which represents one the best results in binary OSCs.

Synthesis of novel laccase-biotitania biocatalysts for malachite green decolorization.

Biomimetic mineralization has emerged as a novel tool for generating excellent supports for enzyme stabilization. In this work, protamine was used to induce titanium (IV) bis(ammonium lactato) dihydroxide (Ti-BALDH) into titania nanoparticles. This biomimetic titanification process was adopted for laccase immobilization. Laccase-biotitania biocatalyst was prepared and the effect of different parameters (buffer solution, titania precursor concentration, protamine concentration, and enzyme loading) on the encapsulation efficiency and recovery of laccase were evaluated. Compared with free laccase, the thermal and pH stability of immobilized laccase were improved significantly. In addition, laccase loaded on titania was effective at enhancing its storage stability. After seven consecutive cycles, the immobilized laccase still retained 51% of its original activity. Finally, laccase-biotitania biocatalysts showed good performance on decolorization of malachite green (MG), which can be attributed to an adsorption and degradation effect. The intermediates of the MG degradation were identified by gas chromatography-mass spectrometry (GC-MS) analysis, and the most probable degradation pathway was proposed. This study provides deeper understanding of the laccase-biotitania particles as a fast biocatalyst for MG decolorization.

Complete mitochondrial genome of the Indonesian whaler shark Carcharhinus tjutjot.

In this study, we first present the complete mitochondrial genome of the Indonesian whaler shark Carcharhinus tjutjot. It is 16,705 bp in length and encodes 37 mitochondrial genes with the typical gene order and transcriptional direction in vertebrates. The overall nucleotide base content is 31.6% A, 26.4% C, 13.0% G and 29.0% T. A total of 33 bp short overlaps and 22 bp short intergenic spaces were found at 9 and 11 gene junctions, respectively. Two initiated codon types (ATG and GTG) and three terminal codon types (TAA, TAG and AGG) were used in the protein-coding genes. The tRNA-Ser2 replaced the DHU arm by a simple loop and could not be folded into the typical secondary structure. The origin of L-strand replication (OL) was identified between the tRNA-Asn and tRNA-Cys genes. The termination-associated sequence (TAS) was found near the tRNA-Pro in the control region.