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BackgroundNitrogen (N) is an essential nutrient element that is involved in almost every aspect of a plant's physiological mechanism. Therefore, the current research aims to determine the optimal amount of N fertilizer to bamboo seedlings for better nutrient management practices to minimize N pollution in bamboo forests. We evaluated the physiological response of Dendrocalamus latiflorus Munro grown under five varying levels of N fertilizer; such as N0, N1, N2, N3, N4, and N5 (0, 1.5, 3.0, 4.5, 6.0, and 7.5 g·pot-1, respectively). ResultsN4 treatment had a significant effect on the number of shoots, which was greatly correlated with net photosynthetic rate (Pn) and photosynthetic pigment (Car, Chls, and Chl a/b) as well as N-related indices [leaf N, leaf ammonium N (NH4+-N), and nitrate reductase (NR)]. N supply significantly increased soil carbon and N contents, which could be conducive to the accumulation of leaf chlorophyll content, improving leaf photosynthesis mechanism, and accelerating N metabolism and conversion through an enzymatic reaction. ConclusionsOverall, the N application of 6 g·pot-1 was advantageous to improve physiological characteristics and shoot production of seedlings. As a consequence, we suggest that optimal nitrogen supply can be effective to improve soil fertility to attain high bamboo production.

Low-overpotential water oxidation catalyzed by copper(ii) porphyrin to produce O2 in neutral aqueous solution and H2O2 in acidic solution., Low overpotential water oxidation under mild conditions is required for new energy conversion technologies with potential application prospects. Extensive studies on molecular catalysis have been performed to gain fundamental knowledge for the rational designing of cheap, efficient and robust catalysts. We herein report a water-soluble CuII complex of tetrakis(4-N-methylpyridyl)porphyrin (1), which catalyzes the oxygen evolution reaction (OER) in neutral aqueous solutions with small overpotentials: the onset potential of the catalytic water oxidation wave measured at current density j = 0.10 mA cm–2 is 1.13 V versus a normal hydrogen electrode (NHE), which corresponds to an onset overpotential of 310 mV. Constant potential electrolysis of 1 at neutral pH and at 1.30 V versus NHE displayed a substantial and stable current for O2 evolution with a faradaic efficiency of >93%. More importantly, in addition to the 4e water oxidation to O2 at neutral pH, 1 can catalyze the 2e water oxidation to H2O2 in acidic solutions. The produced H2O2 is detected by rotating ring–disk electrode measurements and by the sodium iodide method after bulk electrolysis at pH 3.0. This work presents an efficient and robust Cu-based catalyst for water oxidation in both neutral and acidic solutions. The observation of H2O2 during water oxidation catalysis is rare and will provide new insights into the water oxidation mechanism.

Bambusa lapidea is primarily distributed in Guangdong, Guangxi, Sichuan, Yunnan, and Hong Kong in China, occurring on plains, lower hills, and wetlands on both sides of rivers and adjacent to villages. Therefore, we sequenced and reported the complete chloroplast genome of B. lapidea for the first time. The complete chloroplast genome sequence of B. lapidea was generated by de novo assembly using whole-genome next generation sequencing. The genome was 139,525 bp in total length, including a large next-copy (LSC) region of 83,034 bp, a small single-copy (SSC) region of 12,893 bp, a pair of invert repeats (IR) regions of 21,799 bp. The plastid genome contained 127 genes including 83 protein-coding genes, 36 tRNA genes, and eight rRNA genes. Phylogenetic analysis based on 14 chloroplast genomes indicates that B. lapidea is closely related to B. arnhemica sinospinosa and B. teres in Bambusodae.

Six mononuclear and dinuclear platinum(II) terpyridyl acetylide complexes were synthesized and structurally characterized by using single crystal X-ray diffraction. They are [(tpy)Pt−C≡C-SiMe3]PF6 (1, tpy=terpyridine), [(tpy)Pt−C≡CH]PF6 (2), [(tpy)Pt−C≡C–C10H7]PF6 (3, C10H7=1-naphthyl), [(tpy)Pt−C≡C–C14H9]PF6 (4, C14H9=9-anthryl), [(tpy)Pt−C≡C–C10H6-C≡C−Pt(tpy)](CuICl2I) (5, C10H6=1,8-naphthyl), and [(tpy)Pt−C≡C–C14H8-C≡C−Pt(tpy)](PF6)2 (6, C14H8=1,8-anthryl). As catalyzed by copper(I) iodide, reactions of Pt(II) terpyridyl complex [Pt(tpy)Cl]PF6 and corresponding alkynes gave mononuclear complexes 1 (with trimethylsilylacetylene), 3 (with 1-ethynylnaphthalene), 4 (with 9-ethynylanthracene), and gave dinuclear complexes 5 (with 1,8-diethynylnaphthalene) and 6 (with 1,8-diethynylanthracene), respectively. Complex 2, which contains the simplest −C≡CH acetylide ligand, was obtained by removing the trimethylsilyl group in complex 1 through deprotection with tetrabutylammonium fluoride. In all these complexes, the Pt(II) centers are coordinated by a tpy ligand through three N atoms and by an acetylide ligand through a C atom to give a distorted square-planar geometry. In mononuclear complexes 1–4, with Pt⋅⋅⋅Pt and π–π interactions, these square-planar Pt(II) terpyridyl molecules stack with a head-to-tail arrangement to give one-dimensional chains in the solid state. Structural analysis showed that the packing of these Pt(II) terpyridyl molecules in the solid state is largely controlled by the acetylide group through steric effects and π–π interactions. In dinuclear complexes 5–6, the two square-planar Pt(II) terpyridyl units in the same molecule have a face-to-face arrangement, although molecules of 5–6 also stack with a head-to-tail arrangement to give one-dimensional chains in the solid state. The rarely observed face-to-face arrangement of two square-planar Pt(II) terpyridyl units is realized by using pre-organized and rigid dinucleating ligands 1,8-diethynylnaphthalene and 1,8-diethynylanthracene.

A novel selective carbon–carbon single bond cleavage has been disclosed through the copper-catalyzed reaction of 1-alkyl-3-alkylindolin-2-imine hydrochlorides with substituted 1-(bromomethyl)-2-iodobenzenes leading to fused N-heterocycles. Mechanistic studies showed that the intrinsic drive of aromatization and the action of the superbase derived from sodium tert-butoxide and dimethylsulfoxide were the key factors leading to the carbon–carbon single bond cleavage. Furthermore, the obtained N-heterocycles are indoloquinoline derivatives with wide biological activities.

A novel and simple visible-light photoredox intramolecular dearomatization of phenol derivatives containing ketoximes leading to spiropyrrolines has been developed. The protocol uses readily available 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) as the base and electron-donor, visible light as the light source, and the reaction was performed well at room temperature without need of a photocatalyst. Therefore, the present method should provide a useful strategy for synthesis of spiropyrrolines.

Low overpotential water oxidation under mild conditions is required for new energy conversion technologies with potential application prospects. Extensive studies on molecular catalysis have been performed to gain fundamental knowledge for rational design of cheap, efficient and robust catalysts. We herein report a CuII complex of tetrakis(4-N-methylpyridyl)porphyrin (1), which catalyzes the oxygen evolution reaction (OER) in neutral aqueous solution with a small onset overpotential of 290 mV. An unusual coupling of two [Por• −CuII−OH] units is proposed. Experimental and theoretical studies verified that such new O−O bond formation strategy accounts for the observed low overpotential water oxidation. In addition to the 4e water oxidation to O2 at neutral pH, 1 catalyzes the 2e water oxidation to H2O2 in acidic solutions. This work presents an efficient and robust Cu-based catalyst for water oxidation in both neutral and acidic solutions. The proposed O−O bond formation mechanism will enrich the knowledge of molecular catalysis.

An ultrathin Fe-based film was prepared by electrodeposition from an Fe(II) solution through a fast and simple cyclic voltammetry method. The extremely low Fe loading of 12.3 nmol cm(-2) on indium tin oxide electrodes is crucial for high atom efficiency and transparence of the resulted film. This Fe-based film was shown to be a very efficient electrocatalyst for oxygen evolution from neutral aqueous solution with remarkable activity and stability. In a 34 h controlled potential electrolysis at 1.45 V (vs NHE) and pH 7.0, impressive turnover number of 5.2 × 10(4) and turnover frequency of 1528 h(-1) were obtained. To the best of our knowledge, these values represent one of the highest among electrodeposited catalyst films for water oxidation under comparable conditions. The morphology and the composition of the catalyst film was determined by scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray, and X-ray photoelectron spectroscopy, which all confirmed the deposition of Fe-based materials with Fe(III) oxidation state on the electrode. This study is significant because of the use of iron, the fast and simple cyclic voltammetry electrodeposition, the extremely low catalyst loading and thus the transparency of the catalyst film, the remarkable activity and stability, and the oxygen evolution in neutral aqueous media.

Several copper corrole complexes were synthesized, and their catalytic activities for hydrogen (H2) evolution were examined. Our results showed that substituents at the meso positions of corrole macrocycles played significant roles in regulating the redox and thus the catalytic properties of copper corrole complexes: strong electron-withdrawing substituents can improve the catalysis for hydrogen evolution, while electron-donating substituents are not favored in this system. The copper complex of 5,15-pentafluorophenyl-10-(4-nitrophenyl)corrole (1) was shown to have the best electrocatalytic performance among copper corroles examined. Complex 1 can electrocatalyze H2 evolution using trifluoroacetic acid (TFA) as the proton source in acetonitrile. In cyclic voltammetry, the value of icat/ip = 303 (icat is the catalytic current, ip is the one-electron peak current of 1 in the absence of acid) at a scan rate of 100 mV s–1 and 20 °C is remarkable. Electrochemical and spectroscopic measurements revealed that 1 ...

The water-soluble cationic nickel(II) complex of meso-tetrakis(4-N-methylpyridyl)porphyrin (1) can electrocatalyze water oxidation to O2 in neutral aqueous solution (pH 7.0) with the onset of the catalytic wave appearing at ∼1.0 V (vs NHE). The homogeneous catalysis with 1 was verified. Catalyst 1 exhibited water oxidation activity in a pH range 2.0-8.0 and had a strict linear dependence of catalytic current on its concentration. After 10 h of constant potential electrolysis at 1.32 V (vs NHE), a negligible difference of the solution was observed by UV-vis. In addition, inspection of the working electrode by electrochemistry, scanning electron microscope (SEM), and energy dispersive X-ray spectroscopy (EDX) showed no sign of deposition of NiOx films. These results strongly argued that 1 is a real molecular electrocatalyst for water oxidation. The turnover frequency (TOF) for this process was 0.67 s(-1) at 20 °C. On the basis of results from the kinetic isotope effect (KIE) and inhibition experiments, electrochemical studies in various buffer solutions with different anions and pHs, and DFT calculations, a catalytic cycle of 1 for water oxidation via a formally Ni(IV) species was proposed.

A simple and robust microfluidic device was developed to synthesize organometallic polymers with highly organized structures. The device is compatible with organic solvents. Reactants are loaded into pairs of reservoirs connected by a 15 cm long microchannel prefilled with solvents, thus allowing long-term counter diffusion for self-assembly of organometallic polymers. The process can be monitored, and the resulting crystalline polymers are harvested without damage. The device was used to synthesize three insoluble silver acetylides as single crystals of X-ray diffraction quality. Importantly, for the first time, the single-crystal structure of silver phenylacetylide was determined. The reported approach may have wide applications, such as crystallization of membrane proteins, synthesis and crystal growth of organic, inorganic, and polymeric coordination compounds, whose single crystals cannot be obtained using traditional methods.

Cobalt corroles with different acid/base pendants, LBr–Co, LCOOH–Co, LPO(OH)2–Co, and LCH2PO(OH)2–Co (L = 5,15-bis-(pentafluorophenyl)-10-(4-dibenzofuran)corrole), were synthesized and examined as catalysts for oxygen and hydrogen evolution from neutral aqueous solutions. Co corroles with phosphonic acid pendants showed improved activities in both processes, highlighting the importance of the secondary coordination sphere in catalyst design.

Six cobalt and manganese corrole complexes were synthesized and examined as single-site catalysts for water splitting. The simple cobalt corrole [Co(tpfc)(py)2] (1, tpfc = 5,10,15-tris(pentafluorophenyl)corrole, py = pyridine) catalyzed both water oxidation and proton reduction efficiently. By coating complex 1 onto indium tin oxide (ITO) electrodes, the turnover frequency for electrocatalytic water oxidation was 0.20 s(−1) at 1.4 V (vs. Ag/AgCl, pH = 7), and it was 1010 s(−1) for proton reduction at −1.0 V (vs. Ag/AgCl, pH = 0.5). The stability of 1 for catalytic oxygen evolution and hydrogen production was evaluated by electrochemical, UV-vis and mass measurements, scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDX), which confirmed that 1 was the real molecular catalyst. Titration and UV-vis experiments showed that the pyridine group on Co dissociated at the beginning of catalysis, which was critical to subsequent activation of water. A proton-coupled electron transfer process was involved based on the pH dependence of the water oxidation reaction catalyzed by 1. As for manganese corroles 2–6, although their oxidizing powers were comparable to that of 1, they were not as stable as 1 and underwent decomposition at the electrode. Density functional theory (DFT) calculations indicated that water oxidation by 1 was feasible through a proposed catalytic cycle. The formation of an O–O bond was suggested to be the rate-determining step, and the calculated activation barrier of 18.1 kcal mol(−1) was in good agreement with that obtained from experiments.

A nickel(II) porphyrin Ni-P (P=porphyrin) bearing four meso-C6 F5 groups to improve solubility and activity was used to explore different hydrogen-evolution-reaction (HER) mechanisms. Doubly reduced Ni-P ([Ni-P](2-) ) was involved in H2 production from acetic acid, whereas a singly reduced species ([Ni-P](-) ) initiated HER with stronger trifluoroacetic acid (TFA). High activity and stability of Ni-P were observed in catalysis, with a remarkable ic /ip value of 77 with TFA at a scan rate of 100 mV s(-1) and 20 °C. Electrochemical, stopped-flow, and theoretical studies indicated that a hydride species [H-Ni-P] is formed by oxidative protonation of [Ni-P](-) . Subsequent rapid bimetallic homolysis to give H2 and Ni-P is probably involved in the catalytic cycle. HER cycling through this one-electron-reduction and homolysis mechanism has been proposed previously but rarely validated. The present results could thus have broad implications for the design of new exquisite cycles for H2 generation.

A porous Ni–Fe oxide is presented as an efficient water oxidation electrocatalyst by W. Zhang, R. Cao, and co‐workers in article number 1500199. The catalyst is constructed by evaporation of an organic surfactant from the layered Ni–Fe material under mild thermal treatment. The low evaporation temperature preserves the high surface area of the material, and is also ideal for formation of the highly active Fe‐incorporated NiO electrocatalyst.

Water oxidation is the key step in natural and artificial photosynthesis for solar-energy conversion. As this process is thermodynamically unfavorable and is challenging from a kinetic point of view, the development of highly efficient catalysts with low energy cost is a subject of fundamental significance. Herein, we report on iron-based films as highly efficient water-oxidation catalysts. The films can be quickly deposited onto electrodes from Fe(II) ions in acetate buffer at pH 7.0 by simple cyclic voltammetry. The extremely low iron loading on the electrodes is critical for improved atom efficiency for catalysis. Our results showed that this film could catalyze water oxidation in neutral phosphate solution with a turnover frequency (TOF) of 756 h(-1) at an applied overpotential of 530 mV. The significance of this approach includes the use of earth-abundant iron, the fast and simple method for catalyst preparation, the low catalyst loading, and the large TOF for O2 evolution in neutral aqueous media.

A porous Ni–Fe oxide with improved crystallinity has been prepared as a highly efficient electrocatalytic water oxidation catalyst. It has a small overpotential, a low Tafel slope, and an outstanding stability. The remarkably improved electrocatalytic performance is due to the porous structure, high extent homogeneous iron incorporation, ameliorative crystallinity, and the low mass transfer resistance.