Dithio-Fused Boron Dipyrromethenes: Synthesis and Impact of S-Heteroaromatic Annulation Mode.

Three dithio-fused boron dipyrromethenes (BODIPYs), DTFB-1, DTFB-2, and DTFB-3, in which symmetrically S-heteroaromatic ring units fused at [a], zigzag, and [b] bonds of the parent BODIPY core, respectively, were prepared from the facile and efficient post-functionalization of tetra-halogenated BODIPYs through Pd-catalyzed cyclization. Dithio-fusion at various positions of BODIPY effectively tunes their photophysical properties and single-crystal structural packing arrangements. The single-crystalline microribbons of DTFB-2 exhibit commendable hole mobilities in air, reaching up to 0.03 cm2 V-1 s-1.

Electrophotocatalysis Versus Indirect Electrolysis: Electrochemical Selenocyclization of 3-Aza-1,5-dienes Facilitated by Energy Transfer, Direct Photolysis or N-Hydroxyphthalimide.

Three hybrid electrochemical protocols, which involve the energy transfer, direct photolysis and N-hydroxyphthalimide catalyst, respectively, are presented for the selenylation/cyclization of the fragile substrates of 3-aza-1,5-dienes with diorganyl diselenides to afford 3-selenomethyl-4-pyrrolin-2-ones. The two electrophotocatalytic reactions and the indirect electrolysis one are both regioselective and external-oxidant- and transition-metal-free, and are associated with a broad substrate scope and high Se-economy, and all three methods are amenable to gram-scale syntheses, late-stage functionalizations, sunlight-induced experiments and all-solar-driven syntheses.

Mechanofluorochromic behaviors and data security protection properties of salicylaldimine-based difluoroboron complexes with different aryl substituents.

To further explore the relationship between aryl substituents and mechanofluorochromic (MFC) behaviors, four salicylaldimine-based difluoroboron complexes (ts-Ph BF2, ts-Ph-NA BF2, ts-2NA BF2, and ts-triphenylamine [TPA] BF2), including aromatic substituents with different steric hindrance effects, were designed and successfully synthesized. Four complexes with twisted molecular conformation displayed intramolecular charge transfer and aggregation-induced emission properties. Under external mechanical stimuli, the as-synthesized powders of ts-Ph BF2, ts-Ph-NA BF2, and ts-TPA BF2 exhibited redshift fluorescence emission behaviors, and ts-Ph BF2 and ts-TPA BF2 could be recovered to original shifts by fuming, but ts-Ph-NA BF2 displayed irreversible switching. ts-2NA BF2 had no change during the grinding and fuming processes. The results indicated that the MFC behaviors could be attributed to the phase transformation between the well-defined crystalline and disordered amorphous states by X-ray diffraction measurement. Further research illustrated that ts-TPA BF2 with the most significant MFC phenomenon could be applied in data security protection in ink-free rewritable paper.

Hexafluorobutanol primary alcohol ethoxylate-based supramolecular solvent formation and their application in direct microextraction of malachite green and crystal violet from lake sediments.

A new type of hexafluorobutanol (HFB) primary alcohol ethoxylate (AEO)-based supramolecular solvent (SUPRAS) with density higher than water was prepared for the first time. HFB acted as AEO micelle-forming agent and density-regulating agent for SUPRAS formation. The prepared SUPARS was applied as extraction solvent for vortex-assisted direct microextraction of malachite green (MG) and crystal violet (CV) from lake sediment followed by high-performance liquid chromatographic determination. In the present work, SUPRASs prepared from AEO with different carbon chains as the amphiphiles and various coacervation agents were investigated. SUPARS formed from MOA-3 and HFB provided better extraction efficiency in comparison with other SUPRASs. Parameters influencing the extraction recovery of target analytes including the type and volume of AEO, volume of HFB, and vortex time were investigated and optimized. Under optimized conditions, linearity in the range of 2.0-400 µg g-1 for MG and 2.0-500 µg g-1 for CV with a correlation coefficient higher than 0.9947 was obtained. Limits of detection of 0.5 µg g-1 and relative standard deviations in the range of 0.9-5.8% were obtained. Compared to conventional extraction techniques for analysis of analytes in solid samples, the proposed method reduced sample usage and eliminated a primary extraction process by using a toxic organic solvent. The proposed method is simple, fast, and green and can be used for the analysis of target analytes in solid samples.

Intermolecular and Intramolecular Priming Co-directed Synergistic Multi-strand Displacement Amplification Empowers Ultrasensitive Determination of microRNAs.

The construction of isothermal nucleic acid amplification systems with extremely high signal amplification abilities is of great importance for biomarker detection and disease diagnosis. Herein, for the first time, we proposed an intermolecular and intramolecular priming co-directed synergistic multi-strand displacement amplification (SM-SDA) system for microRNA (miRNA) detection. Strategically, the SM-SDA system is made of a single multi-functionalized hairpin probe (MF-HP) that is engineered with a long stem and endowed with target complementation, configuration transformation, enzyme recognition, and signal reporting abilities. The presence of a specific target, the model of miRNA-21, to react with MF-HP would cause an intermolecular priming-directed strand replication in parallel with an intramolecular priming-directed strand replication. The co-directed priming pattern results in the occurrence of SM-SDA containing a target-induced cyclical strand displacement amplification (T-CSDA), a target analogue primer (TAP)-induced CSDA (TAP-CSDA), and a nicked trigger primer (NTP)-induced CSDA (NTP-CSDA). The resulting multiple circuits with a synergetic signal amplification capacity remarkably enhance the target miRNA response, which has not only improved the sensitivity for qualitative and quantitative detection of miRNA but also realized the analysis of target miRNA from real clinical samples. As a proof-of-concept study, this simple but attractive isothermal signal amplification system holds a great potential for molecular diagnosis of diseases and will stimulate interest, new ideas, and discoveries in this fascinating field.

Electroreductive synthesis of polyfunctionalized pyridin-2-ones from acetoacetanilides and carbon disulfide with oxygen evolution.

A chemical reductant or a sacrificial electron donor is required in any reduction reactions, generally resulting in undesired chemical waste. Herein, we report a reductant-free reductive [3 + 2 + 1] annulation of ß-keto amides with CS2 enabled by the synergy of electro/copper/base using water as an innocuous anodic sacrifice with O2 as a sustainable by-product. This electrochemical protocol is mild and provides access to polyfunctionalized pyridin-2-ones from simple starting materials in a single step.

Transcriptomic analysis of cut tree peony with glucose supply using the RNA-Seq technique.

KEY MESSAGE: Several unigenes encoding ACS and ERF involved in ethylene biosynthesis and signal transduction were greatly down-regulated in the petal transcriptome of cut tree peony 'Luoyang Hong' with glucose treatment. Glucose also repressed stress-related transcription factor genes DREB, CBF, NAC, WRKY and bHLH. Tree peony (Paeonia suffruticosa Andrews) is a famous traditional flower in China. Glucose supply prolonging vase life of cut tree peony flowers is associated with its role in the suppression of sensitivity to ethylene and ethylene production, but the regulation mechanism of sugar on ethylene biosynthesis and signaling is unclear. In the present work, a normalized cDNA pool was constructed as the reference transcriptome from mixed petals of different developmental cut tree peony 'Luoyang Hong' and sequenced using the Illumina HiSeq™ 2000 platform. We obtained 33,117 unigenes annotated with public protein databases. In addition, the transcriptome change in petals of cut tree peony with glucose supply and the control treatment was investigated. With non-redundant annotation, 173 differentially expressed genes were identified, with 41 up-regulated genes and 132 down-regulated genes. According to RNA-Seq data and real-time quantitative polymerase chain reaction validation, one unigene encoding ACS, a key ethylene synthetic enzyme, and four unigenes encoding ERF, which is involved in ethylene signal transduction was greatly down-regulated with glucose treatment. Furthermore, stress-related transcription factor genes DREB, CBF, NAC, WRKY and bHLH were also repressed with glucose supply, as well as several other stress-responsive and stress-tolerance genes, indicating that glucose supply probably releases the effects induced by various environmental stress. All the results and analysis are valuable resources for better understanding of the beneficial influence of exogenous sugars on cut tree peony.

The B-H...H-P dihydrogen bonding in ion pair complexes [(CF(3))(3)BH(-)][HPH(3-n)(Me)(n)(+)] (n = 0-3) and its implication in H(2) elimination and activation reactions.

The B-H(delta-)...(delta+)H-P dihydrogen bonding (DHB) in ion pair complexes [(CF(3))(3)BH(-)][HPH(3-n)(Me)(n)(+)] (n = 0-3) and its role in the combination of proton and hydride with the release of H(2) or, reversibly, the heterolytic activation of H(2) by Lewis pairs (CF(3))(3)BPH(3-n)(Me)(n) have been theoretically investigated at the MP2 and DFT levels. It is found that the B-H...H-P bonds behave similarly to those in neutral pairs and ion-molecule complexes in most respects, such as the linearity of the H...H-P moiety, the characteristics of the electron transfer and rearrangement, and the topological properties of the DHB critical point, except that in certain cases, a blue-shifting of the H-bond vibrational frequency is observed. In [(CF(3))(3)BH(-)][HPH(3-n)(Me)(n)(+)], the proton shifting within the complexes leads to the formation of the dihydrogen complex B(CF(3))(3)(eta(2)-H(2)), which is followed by a subsequent H(2) release. The stability of B(CF(3))(3)(eta(2)-H(2)) (D(e)/D(0) = 10.8/6.0 kcal/mol) makes the proton-hydride combination proceed in a fashion similar to the protonation reactions in transition-metal hydrides rather than those in group 13 hydrides EH(4)(-) (E = B, Al, Ga). As for the H(2)-splitting reaction R(3)BPR'(3) + H(2) --> [R(3)BH(-)][HPR'(3)(+)], classical Lewis pair (CLP) (CF(3))(3)BPH(3) exhibits a high barrier and results in an unstable ion pair product [(CF(3))(3)BH(-)][HPH(3)(+)] compared with the "frustrated Lewis pair" (FLP) (C(6)F(5))(3)BP(tBu)(3). A detailed analysis of the mechanistic aspects of H(2) activation by (CF(3))(3)BPH(3) and (C(6)F(5))(3)BP(tBu)(3), supported by another CLP (CF(3))(3)BP(tBu)(3) which has a binding energy comparable to (CF(3))(3)BPH(3) but a reaction exothermicity comparable to (C(6)F(5))(3)BP(tBu)(3), allows us to suggest that the low stability of FLP (C(6)F(5))(3)BP(tBu)(3) is the determining factor for the low reaction barrier. The relative stability and other properties of the ion pair products [R(3)BH(-)][HPR'(3)(+)] have also been analyzed. Results strongly support the view proposed by Rokob et al. [ Rokob , T. A. ; Hamza , A. ; Stirling , A. ; Soos , T. ; Papai , I. Angew. Chem., Int. Ed. 2008 , 47 , 2435 ] that the frustration energy lowers the energy barrier and increases the exothermicity of the reaction.