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Summary It is highly attractive and challenging to utilize carbon dioxide (CO2), because of its inertness, as a nontoxic and sustainable C1 source in the synthesis of valuable compounds. Here, we report a novel selective carboxylation of C(sp3)−F bonds with CO2 via visible-light photoredox catalysis. A variety of mono-, di-, and trifluoroalkylarenes as well as α,α-difluorocarboxylic esters and amides undergo such reactions to give important aryl acetic acids and α-fluorocarboxylic acids, including several drugs and analogs, under mild conditions. Notably, mechanistic studies and DFT calculations demonstrate the dual role of CO2 as an electron carrier and electrophile during this transformation. The fluorinated substrates would undergo single-electron reduction by electron-rich CO2 radical anions, which are generated in situ from CO2 via sequential hydride-transfer reduction and hydrogen-atom-transfer processes. We anticipate our finding to be a starting point for more challenging CO2 utilization with inert substrates, including lignin and other biomass.

An efficient, mild, and atom-economical synthesis of benzo[b]fluorenols from 1,6-enynes has been developed under photocatalytic conditions. A single P/N heteroleptic Cu(I)-photosensitizer might exhibit both energy-transfer and photoredox catalytic activities in the formation of benzo[b]fluorenols.

A deoxygenative radical alkylation of aromatic alkynes with alkyl aldehydes for the preparation of allylarenes has been successfully achieved. This transformation is accomplished through the reacti...

A series of novel 4,7-dicarbazol-1,10-phenanthroline bidentate N-ligands have been designed and synthesized, and applied in heteroleptic copper complexes [Cu(PˆP)(NˆN)]+ as photosensitizers (PS) for light-driven water reduction. In combination with a water reduction catalyst (WRC), Fe3CO12, photocatalytic performances up to 1036 turnover numbers (TON) were reached. This excellent performance can be attributed to the introduction of carbazole groups to the phenanthroline backbone, which can increase the fluorescence quantum yield, decrease the reduction potential of the copper complexes and switch the excited state quenching mechanism from reductive to oxidative. By means of DFT calculations, it has been established that the carbazole substituent contributes most significantly to the HOMO of these complexes.

An efficient water reduction system was developed using thermally activated delayed fluorescence (TADF) dyes as organic photosensitizers and a palladium complex as water reduction catalyst. 2,4,5,6-tetrakis(carbazol-9-yl)-1,3-dicyanobenzene (4CzIPN) that has the best fluorescence efficiency displayed the highest photoinduced productivity (TON up to 2567) and was active for 5 days. Based on time-resolved photoluminescence experiments on the photocatalytic system, reductive quenching of the TADF dye was found as main pathway occurring before intersystem crossing takes place.

An efficient, mild, and atom-economical synthesis of benzo[

Mild [2 + 2] photodimerization of enone substrates was induced by donor–acceptor fluorophores. Enone substrates were activated efficiently for anti-head to head dimerizations with a high yield (up to 83%) and high selectivity. The adjustable excited state potential also allows donor–acceptor fluorophores to be used for isomerization of the above substrates, confirming the potential of donor–acceptor fluorophores as energy transfer photocatalysts.

Homogenous photocatalytic systems based on copper photosensitizers are promising candidates for noble metal free approaches in solar hydrogen generation. To improve their performance, a detailed understanding of the individual steps is needed. Here, we study the interaction of a heteroleptic copper (I) photosensitizer with an iron catalyst by time-resolved spectroscopy and ab initio calculations. The catalyst leads to rather efficient quenching of the 3MLCT state of the copper complex, with a bimolecular rate being about three times smaller than the collision rate. Using control experiments with methyl viologen, an appearing absorption band is assigned to the oxidized copper complex demonstrating that an electron transfer from the sensitizer to the iron catalyst occurs and the system reacts along an oxidative pathway. However, only about 30% of the quenching events result in an electron transfer while the other 70% experience deactivation indicating that the photocatalytic performance might suffer from geminate recombination.

The first catalytic hydrocarboxylation of enamides and imines with CO2 to generate valuable α,α-disubstituted α-amino acids is reported. Notably, excellent chemo- and regio-selectivity are achieved, significantly different from previous reports on β-carboxylation of enamides, homocoupling or reduction of imines. Moreover, this transition-metal-free procedure exhibits low loading of an inexpensive catalyst, easily available substrates, mild reaction conditions, high efficiency, facile scalability and easy product derivatization, providing great potential for application in organic synthesis, pharmaceutical chemistry, and biochemistry.

The wild hawthorn species, Crataegus songorica K. Koch., is an important wild germplasm resource in Xinjiang, China that has been endangered in recent years. The genetic diversity of C. songorica K. Koch. germplasm in five populations from Daxigou, Xinjiang, China were evaluated based on phenotypic traits and ISSR molecular markers to provide basic information on resource protection, rational utilization and genetic improvement. The F-value for the phenotypic differentiation coefficient of the 33 traits measured ranged from 0.266 to 15.128, and mean value was 13.85%. The variation among populations was found to be lower than that within population. A total of 303 loci were detected within the five populations by 12 primers. Within 298 polymorphic loci, the polymorphism was 98.35%, showing a high genetic diversity in C. songorica K. Koch. The gene diversity within population, total population genetic diversity, genetic differentiation coefficient and gene flow were 0.2779, 0.3235, 0.1408, and 3.0511, respectively. Our results showed that C. songorica K. Koch. from Xinjiang has a high level of genetic diversity at both the phenotypic and molecular levels. Significant genetic differentiation existed within population and the differentiation trend showed a regional association. And in this study, in situ and ex situ conservation approaches were raised for wild hawthorn protection utilization.

A series of phenanthroline-based ligands have been synthesised and their influence as bidentate nitrogen ligands in heteroleptic [Cu(P^P)(N^N)]+ photosensitisers in light-driven water reduction has been studied. In this noblemetal- free Cu–Fe-based photocatalytic water reduction system, the structural effects of the nitrogen ligands have been explored, including the steric and electronic effects of substituents at the 2,9- and 4,7-positions of phenanthroline. Ligands were prepared that led to increased hydrogen generation, with turnover numbers (TONCu) of up to 1388 being observed. All the new complexes were electrochemically and photophysically characterised. We demonstrate for the first time that the presence of fluorine in nitrogen ligands increases the efficacy of copper complexes in photocatalytic hydrogen production.

The development of cost-effective, sustainable, and efficient catalysts for liquid organic hydrogen carrier systems is a significant goal. However, all the reported liquid organic hydrogen carrier systems relied on the use of precious metal catalysts. Herein, a liquid organic hydrogen carrier system based on non-noble metal catalysis was established. The Mn-catalyzed dehydrogenative coupling of methanol and N,N’-dimethylethylenediamine to form N,N’-(ethane-1,2-diyl)bis(N-methylformamide), and the reverse hydrogenation reaction constitute a hydrogen storage system with a theoretical hydrogen capacity of 5.3 wt%. A rechargeable hydrogen storage could be achieved by a subsequent hydrogenation of the resulting dehydrogenation mixture to regenerate the H2-rich compound. The maximum selectivity for the dehydrogenative amide formation was 97%., The development of cost-effective, sustainable, and efficient catalysts for liquid organic hydrogen carrier systems is a significant goal. Herein, authors present a system based on manganese catalysis with a theoretical H2 capacity of 5.3 wt% and high selectivity for the dehydrogenation reaction.

The [2 + 2] photodimerization of chalcones, cinnamates and cinnamamides can be effectively catalyzed by heteroleptic copper(I) complexes. The reactions were carried out under mild reaction conditions and the products were obtained in 20–72% yield under visible light irradiation. The copper-based photocatalyst comprised of the rigid phenanthroline ligand with substituents at the 2,9-positions and the 4,7-positions showed high activity in the photodimerization via an energy transfer pathway.

A series of dibenzo[b,j]-1,10-phenanthroline derivatives as N ligands was synthesized and their heteroleptic copper complexes obtained in-situ. These were applied as photosensitizer in photocatalyticCu-Fe water reduction system. Thixantphos as P ligand and 5,8-diphenyl-6,7-dihydrodibenzo[b,j] [1,10]phenanthroline as N ligands constitutes the most efficient photosensitizer among the tested photosensitizer. The highest turnover number of copper was up to 441 and the system achieved a stability of 15 h. Photophysical and electronic chemical character showed that the longer exited time of Cu complex is the reason for the higher photosensitive activity. By theoretical calculation it could be proven that ligand-to-ligand charge transfer is the main energy transition method. Noteworthy, for the first time it could be detected and explained why a C-C single bond at 6,7 positions of phenanthroline could significantly increase the light conversion efficiency. This is a result of the lower N ligand contribution in HOMO and the wider energy gap.

Herein, we report a novel cobalt-catalyzed stereodivergent transfer hydrogenation of alkynes to Z- and E-alkenes. Effective selectivity control is achieved based on a rational catalyst design. Moreover, this mild system allows for the transfer hydrogenation of alkynes bearing a wide range of functional groups in good yields using catalyst loadings as low as 0.2 mol %. The general applicability of this procedure is highlighted by the synthesis of more than 50 alkenes with good chemo- and stereoselectivity. A preliminary mechanistic study revealed that E-alkene product was generated via sequential alkyne hydrogenation to give Z-alkene intermediate, followed by a Z to E alkene isomerization process.

In situ generated iron‐based Knölker complexes were found to be efficient catalysts in a fully non‐noble metal Cu–Fe photocatalytic water reduction system. These mononuclear iron catalysts were able to generate hydrogen up to 15 times faster than previously reported [Fe3(CO)12]. A reductive quenching mechanism was shown to operate by fluorescence experiments.

Fruit size is one of the most important agronomic characters, which is mainly determined by cell number and cell size. However, our current knowledge about pear is largely unknown. Through counting of pear mesocarp cells at different stages, we found that the cell number, rather than the cell size, is responsible for the differences between small- and large-fruited cultivars. Fruit weight-2.2 (fw2.2) is an important quantitative trait locus (QTL) affecting fruit weight in tomato and functions as a negative regulator in carpel cell division. To get more insights into this QTL in pear fruit development, we isolated two putative homologous fw2.2 genes, which were designated as fw2.2-like (PbFWL) genes. PbFWLs encode Cys-rich proteins with the CCXXXXCPC motif and belong to the PLAC8 superfamily. In addition, results from the subcellular localization indicated that PbFWLs were localized in the plasma membrane. The expression profile of the PbFWL genes by qRT-PCR showed they expressed higher in small-sized fruit cultivar than that in large-sized fruit cultivar during the cell division period. In summary, our data suggest that these two PbFWLs might be negatively related to the cell division in pear fruit.

Two novel heteroleptic Cu(I) complexes with the single tetradentate ligands have been designed and synthesized from phenanthroline. The complexes having one copper structure were fully characterized by NMR, ESI-MS and the single-crystal X-ray structures. Their photoelectric chemical properties were investigated by using cyclic voltammetry, UV/vis and fluorescence spectroscopy. Compared with the classic Cu(P^P)(N^N) complexes, this distorted tetrahedral coordination structure of Cu(P^N^N^P) complexes showed a wider excitation wavelength and a red-shifted about 100 nm emission peak, due to the link function between phenanthroline and phosphorus ligands. Moreover, the copper complex B having the naphthyl link groups displayed high red-emissive photoluminescence quantum efficiency (PLQY), which was up to 3.8%.

The discovery of highly efficient photocatalysts for water splitting remains a challenge of high importance. Here, we report a series of novel organic conjugated polymers (OCPs) that contain complexed non‐noble metals for photocatalytic hydrogen evolution. The conjugated chromophore polymers were synthesized by a Heck coupling between ferrocene and phenantholine derivatives, which absorb broadly, even up to the near‐IR region. The photocatalyst performances were investigated for hydrogen evolution by using Fe3(CO)12 as a water reduction catalyst. H2 evolution rates up to 212.4 μmol h−1, with an apparent quantum yield of 10.3 % at 380 nm, were obtained with a photocatalyst polymer based on alternating ferrocene and 4,7‐bisphenyl‐1,10‐phenanthroline units. The high activity is likely due to favorable electron transfer and coordination of Fe3(CO)12 with phenanthroline in the supramolecular OCPs.

Aphidophagous syrphids are important for pest control and pollination in various agroecosystems. However, the mechanism underlying olfaction, which is critical for insect' behavioral processes and fitness, has not been well understood in the family Syrphidae. Hence, we performed a systematic identification and characterisation of the antennal sensilla and two groups of soluble proteins, odorant-binding proteins (OBPs) and chemosensory proteins (CSPs), in the hoverfly Eupeodes corollae. (i) With scanning electron microscopy, four major types of sensilla (chaetic sensilla [two subtypes], trichoid sensilla, basiconic sensilla [two subtypes] and coeloconic sensilla), with numerous microtrichia, were first observed along the entire surface of aristate antennae of both sexes of E. corollae. Of these, only chaetic sensillum was found on the first two antennal segments, scape and pedicel, while the other types of sensilla were located on the flagellum. No marked difference was observed in the morphological structure or distributional pattern of any of the sensilla between the two sexes. (ii) By molecular cloning and bioinformatic analysis, 7 EcorCSPs and 28 EcorOBPs (20 classic OBPs, 5 minus-C OBPs, and 3 plus-C OBPs) were directly identified from the species, which all share the characteristic hallmarks of their family, including the presence of a signal peptide and conserved cysteine signature. (iii) RT-qPCR of these chemosensory genes showed predominately tissue-biased expression patterns; 32 of the 35 EcorOBPs/CSPs were uniquely or primarily expressed in the main olfactory organs, either the antennae or head. (iv) Among these, several genes (EcorCSP2 and EcorOBP1, 9, 12, 15-17, 20) appeared to be antenna-biased. In situ hybridization assays indicated that each antenna-biased chemosensory gene was expressed in a different number of cells, suggesting they might play a more vital role in odour recognition and perception and could be potential candidates to study their biological functions in vivo and in vitro. Together, our current findings provide a basis for future studies on how syrphids utilize chemical cues to regulate their behavior during interactions among the natural enemy, its prey, and host plant in agro-ecosystems.

Homogenous photocatalytic systems based on copper photosensitizers are promising candidates for noble metal free approaches in solar hydrogen generation. To improve their performance a detailed understanding of the individual steps is needed. Here, we study the interaction of a heteroleptic copper (I) photosensitizer with an iron catalyst by time-resolved spectroscopy and ab-initio calculations. The catalyst leads to rather efficient quenching of the 3MLCT state of the copper complex, with a bimolecular rate being about three times smaller than the collision rate. Using control experiments with methyl viologen an appearing absorption band is assigned to the oxidized copper complex demonstrating that electron transfer from the sensitizer to the iron catalyst occurs and the system reacts along an oxidative pathway. However, only about 30% of the quenching events result in an electron transfer while the other 70% experience deactivation indicating that the photocatalytic performance could be improved by optimizing the intermolecular interaction.

In China, Adelphocoris lineolatus (Goeze) (Hemiptera: Miridae) is an important pest of alfalfa, cotton, and other crops, while Peristenus spretus (Chenvan Achterberg) (Hymenoptera: Braconidae) is the dominant nymphal parasitoid of this mirid bug. In the present study, the toxicity of 17 common insecticides to A. lineolatus was evaluated, and the susceptibility of P. spretus to the insecticides with high toxicity to A. lineolatus was tested under laboratory conditions. Of the 17 insecticides tested, 12 (beta cypermethrin, deltamethrin, carbosulfan, acetamiprid, emamectin benzoate, imidacloprid, phoxim, chlorpyrifos, acephate, profenophos, hexaflumuron, and abamectin) had a highly toxic effect on second-instar nymphs of A. lineolatus, with LC(50) values ranging from 0.58 to 14.85 mg a.i. (active ingredient) liter(-1). Adults of P. spretus were most sensitive to chlorpyrifos, with LC(50) values of 0.03 mg a.i. liter(-1), followed by phoxim, acetamiprid, profenophos, carbosulfan, acephate, deltamethrin, emamectin benzoate, imidacloprid, beta-cypermethrin, and abamectin, with LC(50) values ranging from 0.06 to 3.09, whereas hexaflumuron exhibited the least toxicity to the parasitoid, with LC(50) values500 mg a.i. liter(-1). A risk quotient analysis indicated that beta-cypermethrin, emamectin benzoate, abamectin, and hexaflumuron when applied against A. lineolatus were the least toxic to P. spretus.

Although largely neglected, convenient and commercially available copper salts constitute appropriate precursors for efficient and stable water reduction catalysts (WRC). Various copper salts have been applied in the photocatalytic proton reduction together with [Ir(ppy)2(bpy)]PF6 as photosensitizer (PS) and triethylamine (TEA) as electron donor. Among them, copper(I) iodide showed the best productivity, resulting in a TONCu of 260 and a stability of 4 days. The addition of 2,2′-bipyridine (bpy) led to a significant improvement of the catalytic system. Application of 2 equiv. of bpy and an increased amount of PS improved the stability as well as the productivity (TONCu 711). Remarkably, this catalytic system was reactivated seven times with only further addition of fresh PS and TEA. Consequently, this copper-based WRC was shown to be active for more than 48 days reaching a maximum TONCu of >3900, which is in the same order of magnitude as previously known noble metal WRCs. Aberration-corrected HAADF-STEM measurements revealed a part transformation of the molecularly-defined copper precursor into Cu containing nanoparticles of 5–10 nm size. Additionally, by XAS measurements the conversion of the copper(I) salts into Cu(0) compounds under light irradiation was observed. With respect to low costs and high abundance of copper these WRCs are an appropriate alternative for noble metal based catalysts.

This study provides detailed mechanistic insights into light-driven hydrogen production using an abundant copper–iron system. It focuses on the role of the heteroleptic copper photosensitizer [Cu(P∧P)(N∧N)]+, which can be oxidized or reduced after photoexcitation. By means of IR, EPR, and UV/vis spectroscopy as well as computational studies and spectroelectrochemistry, the possibility of both mechanisms was confirmed. UV/vis spectroscopy revealed the reorganization of the original heteroleptic photosensitizer during catalysis toward a homoleptic [Cu(N∧N)2]+ species. Operando FTIR spectroscopy showed the formation of a catalytic diiron intermediate, which resembles well-known hydrogenase active site models.

A series of heteroleptic copper(I) complexes with bidentate PP and NN chelate ligands was prepared and successfully applied as photosensitizers in the light-driven production of hydrogen, by using [Fe3(CO)12] as a water-reduction catalyst (WRC). These systems efficiently reduces protons from water/THF/triethylamine mixtures, in which the amine serves as a sacrificial electron donor (SR). Turnover numbers (for H) up to 1330 were obtained with these fully noble-metal-free systems. The new complexes were electrochemically and photophysically characterized. They exhibited a correlation between the lifetimes of the MLCT excited state and their efficiency as photosensitizers in proton-reduction systems. Within these experiments, considerably long excited-state lifetimes of up to 54 μs were observed. Quenching studies with the SR, in the presence and absence of the WRC, showed that intramolecular deactivation was more efficient in the former case, thus suggesting the predominance of an oxidative quenching pathway.

A series of heteroleptic copper photosensitizers [(P _ P)Cu(N _ N(SO3Na)2)] + containing sulfonate anchor groups is described. In the presence of titanium dioxide they form composites, which are active photosensitizers in the light driven reduction of protons. Further stabilization of these systems is achieved by encapsulation within a plasma-polymerized allylamine (PPAAm) layer. The resulting PPAAm-CuPS-TiO2-composites exhibit a strong absorption in the visible region of the light. Photocatalytic hydrogen production is performed by using only nonnoble metals. In the presence of an iron reduction catalyst a maximum turnover number of 2452 is obtained.

According to the highway subgrade engineering construction period serious delaying by rainy climate for a long time in the tropical rainy regions. The key process of the subgrade construction affected by climate is roadbed filling turning. Binding the law of rainy, Considered the continuous available period for filling turning as a random variable to analyze the correlation with its frequency, established the regression formula, the values of correlation coefficient is more than 0.95, shows that the continuous available period for filling turning presents good exponential relationship, A new statistical method of continuous available period for filling turning called selecting time construction concept was put forward. According the feasible probability of the continuous available period for filling turning, put forward a new grade division method for roadbed filling. Optimized the construction organization of the subgrade engineering by the statistical function of continuous available period for roadbed filling turning, and proved its reliability and achievability. Demonstration and reference were provided for the highway construction and local standardization in southern rainy regions.

An organocatalytic domino thia-Michael/ aldol condensation reaction of α, β-unsaturated aldehydes with 1, 4-dithiane-2,5-diol catalyzed by chiral diphenylprolinol TMS ether has been developed, which provides a new practical and direct route to chiral dihydrothiophenes with high yields (up to 90%) and excellent enantioselectivities (up to>99% ee). The catalytic mechanism of the domino reaction was further confirmed through the APCI-MS detection of proposed reaction intermediates.

An organocatalytic enantioselective Michael addition of 2-hydroxy-1,4-naphthoquinone to β,γ-unsaturated α-oxo esters has been developed. The process was promoted by bifunctional chiral amine derived squaramides according to a hydrogen-bonding mediated activation mechanism and afforded the chiral adducts in high yields (up to 88 %) and excellent enantioselectivity (up to 98 % ee) under mild conditions. This organocatalytic asymmetric Michael addition provides an efficient route toward the synthesis of optically active functionalized naphthoquinones.

The first highly enantioselective organocatalytic Michael addition of 4-hydroxycoumarins is reported.

The self-assembly behavior of ionic liquids with acyclic polyethers was studied. The cations of 1-alkyl-3-methylimidazolium salts and 1-alkylpyridinium salts could form complexes at a ratio of 1:1 with poly(ethylene glycol)-800 (PEG800) and poly(propylene glycol)-1000 (PPG1000) in which the chain length was suitable to wrap around the cations. On the basis of the investigation by NMR, mass spectrometry, UV-vis spectroscopy, and TG analysis, the formation and characteristics of the novel complexes were discussed.

A highly enantioselective Michael reaction of aromatic ketones with nitroolefins was accomplished in the presence of a chiral bifunctional primary amine―thiourea catalyst and 4-nitrobenzoic acid as the co-catalyst; the corresponding adducts were obtained in excellent enantioselectivities (up to 99 % ee) and yields (up to 98 %). The catalytic mechanism of the Michael reaction was confirmed through the ESI-MS detection of proposed reaction intermediates and the 1 H NMR detection of hydrogen bonding between thiourea and the nitroolefins. DFT calculations showed that chiral moieties of the thiourea impacted the yields and enantioselectivities of the adducts remarkably, which corresponds to the observed experimental results.

Generally, amine-catalyzed enantioselective transformations rely on chiral enamine or unsaturated iminium intermediates. Herein, we report a protocol involving dual activation by an aromatic iminium and hydrogen-bonding. An enantioselective aza-Michael–Henry domino reaction of 2-aminobenzaldehydes with nitroolefins has been developed through this protocol using primary amine thiourea catalysts to provide a variety of 3-nitro-1,2-dihydroquinolines in moderate yields and with up to 90 % ee. The mechanism for the catalytic enantioselective reaction was confirmed by ESI mass spectrometric detection of the reaction intermediates. The products formed are substructures found in skeletons of important biological and pharmaceutical molecules.

The duck-rice and fish-rice were two important strategies of pest management in the process of organic rice. The niches and interspecific competitions of wolf spiders and mirid bug, Cyrtorhinus lividipennis under three strategies of pest management in paddy fields were studied in order to understand the influences of different pest control methods on ecological relationships between the two main types of predators. The results of our study suggested that ducks might prey upon wolf spiders resting on the base of rice plants, thus the populations of wolf spiders decreased in duck-rice treatment. The impact of ducks on mirid bug was not significant because it preferred to congregate on the mid-part of rice plants. The temporal selectivity of wolf spiders was smaller than that of mirid bug, which meant occurrence frequency of wolf spiders was higher compared with mirid bug. In addition, competition between wolf spiders and mirid bug was significantly more intense in duck-rice or fish-rice treatment than in natural control treatment at different stages. Probably, ducks and fishes drove wolf spiders away from their original spatial niche, the base to the mid-part in rice plants, enhancing competition between wolf spiders and mirid bug in duck-rice or fish-rice treatment. Based on the results of this study, duck-rice or fish-rice, as a control pest method in the process of organic rice, should be prudentially treated.

Tiefsee-Diels-Alder-Reaktion: Die asymmetrische organokatalytische Diels-Alder-Reaktion zwischen Cyclohexenonen und aromatischen Nitroolefinen gelingt in Meerwasser und gesattigter Kochsalzlosung. Die Reaktion verlauft als saurekatalysierte Enaminaktivierung uber eine einstufige konzertierte Addition (siehe Schema).