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Despite several synthetic approaches that have been developed for α-deuterated amino acids, the synthesis of β-deuterated amino acids has remained a challenge. Herein, we disclose a palladium catalyzed H/D exchange protocol for a β-deuterated N-protected amino amide, which can be converted to a β-deuterated amino acid simply by removal of protecting groups. This protocol is highly efficient, simply manipulated, and appliable for deuterium-labeling of many amino amides. In addition, deuterium labeling of phenylalanine derivatives was also successful when pivalic acid served as an additive to promote the H/D exchange process.

Direct β-arylation of thiophene derivatives with bromide as directing group is disclosed. The reaction is conducted with PdCl2/(p-tolyl)3P as catalyst, silver carbonate as additive, and aryl iodide as coupling partner, affording brominated biaryl compounds as product. Control experiments indicated that the presence of bromide group enhances the reactivity of the C–H bond, enabling β-arylation. Furthermore, the C–Br bond can be easily converted into many useful functional groups through a wide range of methodologies. The mechanistic study suggests that silver salt plays a key role in the C–H bond-activation step.

We disclose a silver catalyzed H/D exchange reaction, which can introduce the deuterium atom at the β position of thiophene rings without the assistance of any coordinating groups. The advantages of this reaction include operation in open air, usage of D

Environmental context Dimethyl sulfide is an important biogenic gas, released from ocean to atmosphere, which contributes to aerosol formation and can therefore affect global climate. Studies on dimethyl sulfide in both seawater and atmosphere have linked the atmospheric chemistry of dimethyl sulfide with its circulation in the marine environment. This study showed that these biogenic emissions contribute to the sulfur cycle and particulate production, deepening our understanding of their role in the East China Sea. Abstract Dimethyl sulfide (DMS) is identified as an essential biogenic sulfur compound in the ocean. Its oxidation products are thought to be important contributors to cloud condensation nuclei, thereby influencing the earth’s radiative balance and climate. The concentrations of DMS and its precursor, dimethylsulfoniopropionate (DMSP) were measured in seawater and sediment pore water in the East China Sea (ECS) during summer. In addition, dissolved DMSP (DMSPd) degradation rates, DMS production and consumption rates, and sea-to-air flux of DMS were determined, and the biogenic contribution to atmospheric non-sea-salt sulfate (nss-SO42−) was evaluated in PM2.5 and PM10 aerosols over the study area. The spatial distributions of DMS and DMSP were closely related to that of chlorophyll-a and decreased from the inshore to the offshore. The concentration of DMSPd in sediment pore water was significantly higher than that in bottom water, which indicated that sediment is a net source of DMSPd for bottom water. The biological incubation experiments showed that ~36.0 % of decomposed DMSPd was degraded into DMS, while 78.7 % of produced DMS was consumed by bacteria within the surface water. The sea-to-air flux of DMS varied from 1.30 to 31.84 μmol m−2 day−1, with an average of 7.45 ± 6.30 μmol m−2 day−1. Biogenic contributions of the ECS to total nss-SO42− were estimated to be 13.0 % ± 9.9 % in PM2.5 and 13.5 % ± 5.1 % in PM10 samples respectively, which indicated that marine DMS release cannot be neglected in the ECS during summer.

Dimethyl sulfide (DMS) is an important and dominant trace gas that is transferred from the ocean to the atmosphere; however, the production of DMS from marine algae is still rudimentary, with the enzymatic cleavage of dimethylsulfoniopropionate (DMSP) to DMS and acrylic acid (AA), one of the main considered pathways. Dissolved DMSP (DMSPd) was supplied to batch cultures of Prorocentrum minimum at different algal growth stages and the kinetics of overall DMSPd consumption and DMS (AA) production were investigated. The kinetics of overall DMSPd consumption and DMS (AA) production from DMSPd were different during the growth cycle. The cultures displayed Michaelis–Menten-type kinetics for DMS production during the entire growth period, which yielded an apparent half-saturation constant (Km(app)) value of 37.8 ± 12.8 μM and a maximum rate (Vmax) value of 75.6 ± 12.2 nmol min−1 (1010 cells)−1. The production rates of AA had a nearly linear fit over the concentration range of the added DMSPd except during mid-exponential growth phase. A Km(app) value of 1.73 ± 0.75 μM and a Vmax value of 2.36 ± 0.12 μmol min−1 (1010 cells)−1 were observed. The ratio of DMS/AA increased with the concentration of the added DMSPd, which was less than 12% during the entire growth period. The low ratios of DMS/(DMSP + AA), which ranged from 0.01 to 1.83%, demonstrate that degradation of DMSP tends to take a non-DMS-production pathway. The ratios of AA/(DMSP + AA) varied from 9 to 95% during the stationary phase and from 6 to 69% during the senescent phase and declined with substrate concentration when different concentrations of DMSPd were added. The degradation ratios of DMSPd were related to the initial concentrations of DMSPd.

Environmental context Marine-derived non-methane hydrocarbons (NMHCs) are thought to affect atmospheric oxidation balance and aerosol formation, hence playing an important role in regulating climate. In this study, we report the distributions and sea-to-air fluxes of 10 NMHCs in the East China Sea (ECS), and assess the roles of phytoplankton assemblages in the occurrence and emission of NMHCs in the ECS. The results will improve our understanding of the biogeochemical cycling of NMHCs in marine systems. Abstract Non-methane hydrocarbons (NMHCs) are important reactive trace-gases that are emitted from oceanic sources. However, it remains unclear how phytoplankton, either total biomass or specific species, affect the generation and emission of NMHCs. This study conducted field observations of NMHCs in the East China Sea (ECS) in autumn, 2014. The mean concentrations of ethane, propane, i-butane, n-butane, pentane, ethene, propene, 1-butene, 1-pentene and isoprene were 20.1 ± 3.6, 20.3 ± 20.2, 4.5 ± 0.9, 10.5 ± 2.3, 14.8 ± 3.4, 63.7 ± 20.8, 23.6 ± 6.6, 7.4 ± 2.9, 15.9 ± 4.3 and 69.4 ± 24.9 pmol L−1 respectively. Horizontal and vertical profiles of NMHCs showed that different water masses had distinct influences and the coastal areas had generally higher concentrations of NMHCs. There were significant positive correlations between alkanes or alkenes, which suggested that their production and fates in the surface seawater were similar. A significant positive correlation was observed between the isoprene and Chl-a concentrations, while no significant correlation was found between Chl-a and any other NMHCs. These results highlighted that, although NMHCs can be produced by phytoplankton, using Chl-a data or phytoplankton assemblages to estimate the production of other NMHCs in seawater is unreliable. Therefore, future research must determine the factors that control the production of these NMHCs. In addition, the results of estimated sea-to-air fluxes of NMHCs underscored the importance of the ECS as a source of NMHCs and the related atmospheric volatile organic compounds.

Aryl bromide is one of the most important compounds in organic chemistry, because it is widely used as synthetic building blocks enabling quick access to a wide array of bioactive molecules, organic materials, and polymers via the versatile cutting-edge transformations of C-Br bond. Direct C-H bond functionalization of aryl bromide is considered to be an efficient way to prepare functionalized aryl bromides; however, it is rarely explored possibly due to the relatively low reactivity of aryl bromide toward C-H bond activation. We herein report a palladium-catalyzed coupling reaction between aryl iodide and aryl bromide for preparing brominated biaryl compounds via a silver-mediated C-H bond activation pathway.

The Pacific Ocean plays an important role in regulating the budget of climatically active gases and the burden of sulfate aerosols. Here, a field investigation was conducted to clarify the key processes and factors controlling climatically active gases, including dimethyl sulfide (DMS), carbonyl sulfide (OCS), carbon disulfide (CS

Dimethylsulfoniopropionate (DMSP) is an important marine osmolyte. Aphotic environments are only recently being considered as potential contributors to global DMSP production. Here, our Mariana Trench study reveals a typical seawater DMSP/dimethylsulfide (DMS) profile, with highest concentrations in the euphotic zone and decreased but consistent levels below. The genetic potential for bacterial DMSP synthesis via the dsyB gene and its transcription is greater in the deep ocean, and is highest in the sediment.s DMSP catabolic potential is present throughout the trench waters, but is less prominent below 8000 m, perhaps indicating a preference to store DMSP in the deep for stress protection. Deep ocean bacterial isolates show enhanced DMSP production under increased hydrostatic pressure. Furthermore, bacterial dsyB mutants are less tolerant of deep ocean pressures than wild-type strains. Thus, we propose a physiological function for DMSP in hydrostatic pressure protection, and that bacteria are key DMSP producers in deep seawater and sediment., Dimethylsulfoniopropionate (DMSP) is an osmolyte produced by marine microbes that plays an important role in nutrient cycling and atmospheric chemistry. Here the authors go to the Mariana Trench—the deepest point in the ocean—and find bacteria are key DMSP producers, and that DMSP has a role in protection against high pressure.

The concentrations of dissolved monosaccharides (MCHO), polysaccharides (PCHO), and total carbohydrates (TCHO) in the seawater samples collected from the north of the Yap Trench in the western Pacific Ocean were measured by 2,4,6-tripyridine-s-triazine (TPTZ) spectrophotometry method. The results show that the concentrations of MCHO, PCHO, and TCHO ranged from 4.6 to 22.1 μmol C/L, 3.5 to 27.3 μmol C/L, and 13.8 to 36.3 μmol C/L, respectively. In different sampling stations, the concentrations of MCHO, PCHO, and TCHO with water depth showed complex variation patterns. In the study area, the maximum concentrations of MCHO, PCHO, and TCHO occurred in the euphotic layer and the minimum concentrations occurred in mesopelagic seawater layer. Generally, the concentrations of MCHO, PCHO, and TCHO decreased with water depth from the euphotic layer to the hadal zone. The average value of PCHO/TCHO was higher than the average value of MCHO/TCHO, indicating that PCHO was the main component of TCHO in north of the Yap Trench.

Seasonal and spatial distributions of dissolved and particulate dimethylsulfoxide (DMSOd, DMSOp) were measured in the East China Sea and the Yellow Sea during March–April 2011 and October–November 2011. The concentrations of DMSOd and DMSOp in the surface water were 20.6 (5.13–73.8) and 8.90 (3.75–29.6) nmol/L in spring, and 13.4 (4.17–42.7) and 8.18 (3.44–22.6) nmol/L in autumn, respectively. Both DMSOd and DMSOp concentrations revealed similar seasonal changes with higher values occurring in spring, mainly because of the higher phytoplankton biomass observed in spring. Moreover, the ratios of DMSOp/chlorophyll a also exhibited an apparent seasonal change with higher values in autumn (35.7 mmol/g) and lower values in spring (23.4 mmol/g), thereby corresponding with the seasonal variation in the proportion of DMSO producers in the phytoplankton community between spring and autumn. In addition, DMSOd and DMSOp concentrations in the surface seawater revealed obvious diurnal variations with the maxima appearing in the afternoon.

By employment of amino-functionalized dicarboxylate ligands to react with d10 metal ions, four novel metal-organic frameworks (MOFs) were obtained with the formula of {[Cd(BCPAB)(μ2-H2O)]}n (1), {[Cd(BDAB)]∙2H2O∙DMF}n (2), {[Zn(BDAB)(BPD)0.5(H2O)]∙2H2O}n (3) and {[Zn(BDAB)(DBPB)0.5(H2O)]∙2H2O}n (4) (H2BCPAB = 2,5-bis(p-carbonylphenyl)-1-aminobenzene; H2BDAB = 1,2-diamino-3,6-bis(4-carboxyphenyl)benzene); BPD = (4,4′-bipyridine); DBPB = (E,E-2,5-dimethoxy-1,4-bis-[2-pyridin-vinyl]-benzene; DMF = N,N-dimethylformamide). Complex 1 is a three-dimensional (3D) framework bearing seh-3,5-Pbca nets with point symbol of {4.62}{4.67.82}. Complex 2 exhibits a 4,4-connected new topology that has never been reported before with point symbol of {42.84}. Complex 3 and 4 are quite similar in structure and both have 3D supramolecular frameworks formed by 6-fold and 8-fold interpenetrated 2D coordination layers. The structures of these complexes were characterized by single crystal X-ray diffraction (SC-XRD), thermal gravimetric analysis (TGA) and powder X-ray diffraction (PXRD) measurements. In addition, the fluorescence properties and the sensing capability of 2–4 were investigated as well and the results indicated that complex 2 could function as sensor for Cu2+ and complex 3 could detect Cu2+ and Ag+via quenching effect.

We measured dissolved methane (CH4) at various depths in the Pearl River Estuary and the shelf, slope, and basin of the northern South China Sea (SCS) during cruises from May to July 2014, October 2014, June 2015, and March 2017. High CH4 concentrations (9.4–430.3 nM) were observed in the Pearl River Estuary. There was a negative correlation between the CH4 concentration and the salinity in the surface waters of the Pearl River Estuary, indicating rapid CH4 loss via air-sea exchange and aerobic CH4 oxidation. The CH4 concentrations in the surface waters ranged from 1.7 to 5.4 nM in the shelf and slope region and from 2.2 to 3.0 nM in the basin of the northern SCS. The injection of a Pearl River plume rich in CH4 and driven by eddies had a profound impact on the CH4 distribution in the shelf and slope region in June 2015. The vertical profiles of CH4 showed spatial variations that can be attributed to complex interactions among physical, chemical, and biological processes. The subsurface CH4 maxima occurred ubiquitously in the euphotic zones, probably due to in situ CH4 production in anoxic microniches and aerobic CH4 formation from potential substrate precursors such as dimethylsulfoniopropionate (DMSP). The gross CH4 production rate in the mixed layer was estimated at 0.11 nM d-1 in the summer and -0.19 nM d-1 in the autumn. The surface waters of the Pearl River Estuary were oversaturated in CH4 with respect to atmospheric equilibrium having a saturation level of 5066±5908% (mean±SD) in early autumn and 6166±3611% in early summer. The CH4 fluxes (estimated using the W14 relationship) were estimated at 314.3±464.9 μmol m-2 d-1 in early autumn and 184.2±187.5 μmol m-2 d-1 in early summer. In the shelf and slope areas, the CH4 saturation was 178±37% in early autumn, 181±60% in early summer, and 129±14% in winter. The sea-to-air CH4 fluxes were 8.0±4.3 μmol m-2 d-1 in autumn, 4.1±5.2 μmol m-2 d-1 in summer, and 1.1±0.8 μmol m-2 d-1 in winter. The CH4 saturation ratio was less variable in the deep basin, ranging from 108% to 184% with an average of 140±16%. The CH4 flux in the deep basin area was 1.9±1.2 μmol m-2 d-1. Overall, we estimate the annual CH4 emission from the SCS as 9.9 × 109 mol yr-1. Hence the SCS is a net source of atmospheric CH4.

Ag2CO3-catalyzed hydrogen isotope exchange of five-membered heteroarenes is disclosed. The reaction can be conducted in the open air, at ambient temperature, and with D2O as deuterium source. Moreover, this protocol showed orthogonal site selectivity to existing technology, thereby greatly expanding the scope of substrates for HIE reaction. The mechanistic study indicated that the carbonate group plays a crucial role to achieve high levels of deuterium incorporation by lowering the activation energy of H/D exchange process.

During an oceanographic campaign in the western Pacific Ocean from 12 August to 3 October 2014, the concentrations of five non-methane hydrocarbons (NMHCs) were measured in marine atmosphere and seawater. The average mixing ratios of ethane, ethylene, propane, propylene, and isoprene were 1.109 ± 0.359, 0.658 ± 0.137, 0.711 ± 0.377, 0.429 ± 0.139, and 0.255 ± 0.201 ppbv, respectively. In general, atmospheric concentrations of ethane and propane showed significant decrease from the inshore area to the open ocean, while ethylene and propylene exhibited decreasing trends from low latitudes to high latitudes. The results suggested that atmospheric ethane and propane with long lifetimes were more likely influenced by the air mass transported from continent, while ethylene, propylene and isoprene with short lifetimes were mainly derived from the surface seawater. The average concentrations of ethane, ethylene, propane, propylene, and isoprene in the surface seawater were 6.6 ± 5.8, 51.9 ± 23.5, 15.4 ± 4.3, 17.2 ± 3.8, and 23.5 ± 8.6 pmol L−1, respectively. A significant positive correlation was observed between ethane and propane (R2 = 0.45, n = 39, p

A series of tetradentate Pt(II) complexes featuring narrow emission spectra have been systematically exploited. The lowest excited states of the molecules can experience delocalized spin transitions during intersystem crossing, leading to local 3ππ* transitions with narrow emission spectra. We found that the photophysical properties expressed by decay lifetimes, radiative decay rates and full width at half maximum (FWHM) values in the spectra correspond to the configurational ratio of the local 3ππ* components, which could be regulated upon structure modification and environmental confinement. Photoluminescent data analysis with zero-field splitting of less than 14 cm−1 stresses the important role of the 3ππ* transitions. Pt(ppzOczpy-4m), simply modified by adding methyl to a Pt(ppzOczpy) frame, gives a 92% photoluminescent yield in dichloromethane and a narrow phosphorescent emission spectrum with a FWHM of 25 nm in the blue region. In application, solution processed deep-blue organic light-emitting devices based on Pt(ppzOczpy-4m) achieve a high maximum external quantum efficiency (EQEmax) of 19.5% with Commission Internationale de L’Eclairage (CIE) coordinates of (0.159, 0.166) and 11.9% EQEmax with optimal CIE coordinates of (0.154, 0.130).

An efficient approach for synthesizing congested deuterium-labeled arenes via cascade alkylation and deuteration with aryl iodides has been disclosed. We found that the adoption of sodium formate-d as a deuterium source is the key for achieving high deuterium incorporation >98%.

A mesocosm experiment was conducted in Wuyuan Bay (Xiamen), China, to investigate the effects of elevated p CO2 on the phytoplankton species Phaeodactylum tricornutum (P. tricornutum), Thalassiosira weissflogii (T. weissflogii) and Emiliania huxleyi (E. huxleyi) and their production ability of dimethylsulfide (DMS), dimethylsulfoniopropionate (DMSP), as well as four halocarbon compounds, bromodichloromethane ( CHBrCl2 ), methyl bromide ( CH3Br ), dibromomethane ( CH2Br2 ) and iodomethane ( CH3I ). Over a period of 5 weeks, P. tricornuntum outcompeted T. weissflogii and E. huxleyi, comprising more than 99 % of the final biomass. During the logarithmic growth phase (phase I), mean DMS concentration in high p CO2 mesocosms (1000 µ atm) was 28 % lower than that in low p CO2 mesocosms (400 µ atm). Elevated p CO2 led to a delay in DMSP-consuming bacteria concentrations attached to T. weissflogii and P. tricornutum and finally resulted in the delay of DMS concentration in the high p CO2 treatment. Unlike DMS, the elevated p CO2 did not affect DMSP production ability of T. weissflogii or P. tricornuntum throughout the 5-week culture. A positive relationship was detected between CH3I and T. weissflogii and P. tricornuntum during the experiment, and there was a 40 % reduction in mean CH3I concentration in the high p CO2 mesocosms. CHBrCl2 , CH3Br , and CH2Br2 concentrations did not increase with elevated chlorophyll a (Chl a) concentrations compared with DMS(P) and CH3I , and there were no major peaks both in the high p CO2 or low p CO2 mesocosms. In addition, no effect of elevated p CO2 was identified for any of the three bromocarbons.

Dimethylated sulfur compounds play an important role in global sulfur cycle. We investigated the seasonality of dimethylsulfoniopropionate (DMSP), dimethylsulfoxide (DMSO), dimethylsulfide (DMS) and associated processes in two north China marginal seas during 2014 and 2016. High concentrations of DMS, DMSP and DMSO occurred in summer/spring, while the lowest were observed in winter. This clear seasonality was primarily driven by biomass abundance and phytoplankton communities, reflected in chlorophyll a concentrations and the composition/ratios of diatoms and dinoflagellates. The spring maximum was attributed to the annual occurrence of algal bloom. The sea-to-air fluxes of DMS also varied largely between seasons, with an average of 8.84, 11.87, 10.50 and 2.14 μmol m−2 day−1 in spring, summer, autumn and winter, respectively. Given the seasonal uncertainty of sea-to-air flux, the seasonality or situations where specific blooms occur regularly should be considered for accurate estimation of annual global DMS emission.