An Efficient C-Si/C-H Cross-Coupling Reaction Enabled by a Radical Pathway.

The methods for the cross-coupling of aryl(trialkyl)silanes are long-standing challenges due to the extreme inertness of C-Si(R3) bond, though the reaction is environmentally friendly and highly regioselective to synthesize biaryls. Herein, we report a copper-catalyzed cross-coupling of aryl(trialkyl)silanes and aryl via a radical mechanism. The reaction proceeds efficiently with aryl sulfonium salts as limiting reagents, exhibits broad substrate scope, and provides an important synthetic strategy to acquire biaryls, exemplified by unsymmetrical fluorescence probes and late-stage functionalization of drugs. Of note, the experimental and theoretical mechanistic studies revealed a radical mechanism where the copper catalyst and CsF play critical roles on the radical generation and desilylation process.

General room-temperature Suzuki-Miyaura polymerization for organic electronics.

π-Conjugated polymers (CPs) have broad applications in high-performance optoelectronics, energy storage, sensors and biomedicine. However, developing green and efficient methods to precisely synthesize alternating CP structures on a large scale remains challenging and critical for their industrialization. Here a room-temperature, scalable and homogeneous Suzuki-Miyaura-type polymerization reaction is developed with broad generality validated for 24 CPs including donor-donor, donor-acceptor and acceptor-acceptor connectivities, yielding device-quality polymers with high molecular masses. Furthermore, the polymerization protocol significantly reduces homocoupling structural defects, yielding more structurally regular and higher-performance electronic materials and optoelectronic devices than conventional thermally activated polymerizations. Experimental and theoretical studies reveal that a borate transmetalation process plays a key role in suppressing protodeboronation, which is critical for large-scale structural regularity. Thus, these results provide a general polymerization tool for the scalable production of device-quality CPs with alternating structural regularity.

Room Temperature Anhydrous Suzuki-Miyaura Polymerization Enabled by C-S Bond Activation.

The Suzuki-Miyaura cross-coupling is one of the most important and powerful methods for constructing C-C bonds. However, the protodeboronation of arylboronic acids hinder the development of Suzuki-Miyaura coupling in the precise synthesis of conjugated polymers (CPs). Here, an anhydrous room temperature Suzuki-Miyaura cross-coupling reaction between (hetero)aryl boronic esters and aryl sulfides was explored, of which universality was exemplified by thirty small molecules and twelve CPs. Meanwhile, the mechanistic studies involving with capturing four coordinated borate intermediate revealed the direct transmetalation of boronic esters in the absence of H2 O suppressing the protodeboronation. Additionally, the room temperature reaction significantly reduced the homocoupling defects and enhanced the optoelectronic properties of the CPs. In all, this work provides a green protocol to synthesize alternating CPs.

An Efficient Direct Arylation Polycondensation via C-S Bond Cleavage.

The direct arylation polycondensation (DArP) has become one of the most important methods to construct conjugated polymers (CPs). However, the homocoupling side-reactions of aryl halides and the low regioseletive reactivities of unfunctionalized aryls hinder the development of DArP. Here, an efficient Pd and Cu co-catalyzed DArP was developed via inert C-S bond cleavage of aryl thioethers, of which robustness was exemplified by over twenty conjugated polymers (CPs), including copolymers, homopolymers, and random polymers. The capture of oxidative addition intermediate together with experimental and theoretic results suggested the important role of palladium (Pd) and copper (Cu) co-catalysis with a bicyclic mechanism. The studies of NMR, molecular weights, trap densities, two-dimensional grazing-incidence wide-angle X-ray scattering (2D-GIWAXS), and the charge transport mobilities revealed that the homocoupling reactions were significantly suppressed with high regioselectivity of unfunctionalized aryls, suggesting this method is an excellent choice for synthesizing high performance CPs.

Comment on "Sexual selection promotes giraffoid head-neck evolution and ecological adaptation".

Wang et al. (Research Articles, 3 June 2022, eabl8316) reported an early Miocene giraffoid that exhibited fierce head-butting behavior and concluded that sexual selection promoted head-neck evolution in giraffoids. However, we argue that this ruminant is not a giraffoid and thus that the hypothesis that sexual selection promoted giraffoid head-neck evolution is not sufficiently supported.

Coupling and Coordinative Development of Green Finance and Industrial-Structure Optimization in China: Spatial-Temporal Difference and Driving Factors.

Although the literature has studied the direction and extent of the effect of green finance on industrial-structure optimization, quantitative analysis of the coupling coordination and spatial-temporal differences between green finance and industrial structure is relatively scarce. Therefore, in this paper, we built the theoretical framework of the coupling coordination relationship between green finance and industrial-structure optimization, and then we used the coupling coordination degree and geographic detector model to investigate the spatial-temporal evolution characteristics and influencing factors of the coupling coordination between the two based on the panel data of 31 provinces from 2012 to 2019. The results show that China's green finance and industrial-structure optimization have basically reached the primary coupling, and the coupling coordination degree is from 0.40 to 0.43, which shows a "W"-type fluctuation trend of recovery. The regional gap of the coupling coordination degree firstly decreased and then increased, showing a change law of "agglomeration, equilibrium and agglomeration". In the spatial dimension, the high-level coordination region showed an increasing trend of "fragmentation" fluctuation, while the low-level coordination region concentrated in the central and western regions with a tendency of "low value locking". The trend surface showed a spatial characteristic of "high in the north and low in the south-high in the east and west and low in the middle". We also found that the dependence of foreign trade and technological innovation are the main factors affecting the coupling coordination degree, and the interaction between government support and human capital synergistic is the crucial channel for the coevolution of green finance and industrial structure to promote green and low-carbon development.

Virtual Water Flow Pattern in the Yellow River Basin, China: An Analysis Based on a Multiregional Input-Output Model.

Research on the Yellow River Basin's virtual water is not only beneficial for rational water resource regulation and allocation, but it is also a crucial means of relieving the pressures of a shortage of water resources. The water stress index and pull coefficient have been introduced to calculate the implied virtual water from intraregional and interregional trade in the Yellow River Basin on the basis of a multi-regional input-output model; a systematic study of virtual water flow has been conducted. The analysis illustrated that: (1) Agriculture is the leading sector in terms of virtual water input and output among all provinces in the Yellow River Basin, which explains the high usage. Therefore, it is important to note that the agricultural sector needs to improve its water efficiency. In addition to agriculture, virtual water is mainly exported through supply companies in the upper reaches; the middle reaches mainly output services and the transportation industry, and the lower reaches mainly output to the manufacturing industry. Significant differences exist in the pull coefficients of the same sectors in different provinces (regions). The average pull coefficients of the manufacturing, mining, and construction industries are large, so it is necessary to formulate stricter water use policies. (2) The whole basin is in a state of virtual net water input, that is, throughout the region. The Henan, Shandong, Shanxi, Shaanxi, and Qinghai Provinces, which are relatively short of water, import virtual water to relieve local water pressures. However, in the Gansu Province and the Ningxia Autonomous Region, where water resources are not abundant, continuous virtual water output will exacerbate the local resource shortage. (3) The Yellow River Basin's virtual water resources have obvious geographical distribution characteristics. The cross-provincial trade volume in the downstream area is high; the virtual water trade volume in the upstream area is low, as it is in the midstream and downstream areas; the trade relationship is insufficient. The Henan and Shandong Provinces are located in the dominant flow direction of Yellow River Basin's virtual water, while Gansu and Inner Mongolia are at the major water sources. Trade exchanges between the midstream and downstream and the upstream should be strengthened. Therefore, the utilization of water resources should be planned nationwide to reduce water pressures, and policymakers should improve the performance of agricultural water use within the Yellow River Basin and change the main trade industries according to the resource advantages and water resources situation of each of them.

Identifying the Spatial Imbalance in the Supply and Demand of Cultural Ecosystem Services.

Cultural ecosystem services (CESs) are an important part of ecosystem services (ESs). Correctly understanding the supply and demand relationship of CES is the premise of ES sustainable management and helps to improve human well-being. However, the evaluation and mapping of CES supply and demand represents a significant gap in ES research. Using the Shigou Township of Mizhi County in China as an example, in this study, we evaluated CES supply and demand at the village scale. We first considered three aspects of supply potential, accessibility and quality to construct an indicator system of six types of CES supply, including aesthetic (Aest), sense of place (SP), social relations (SR), cultural heritage (Cult), education (Edu) and recreation (Recr) and obtained demand data through a questionnaire. Then, we identified the imbalance in the supply and demand of CES by Z-score standardization based on the quantification of the CES supply and demand. Secondly, bivariate spatial autocorrelation analysis was used to identify tradeoffs/synergies on the CES supply side, and chi-square tests were used to identify CES demand differences between stakeholder groups. The results indicated that the supply-demand patterns of CES presented evident spatial differences. The low-supply-high-demand patterns of Aest, SR and Recr accounted for the largest proportions, with values of 33.33%, 33.33% and 30.95%, respectively. The low-supply-low-demand patterns of SP and Cult accounted for the largest proportions, with values of 30.95% and 38.10%, respectively. The low-supply-low-demand pattern of Edu accounted for the smallest proportion (21.43%) and was mainly located in the south of Shigou Township. The southwest, northeast and central areas of Shigou Township were the key regions of tradeoffs/synergies of CES supply. There were significant differences in CES demand for SR, Cult and Edu among stakeholder groups. The results could contribute to optimizing regional ecosystem management and provide effective information for improving the imbalance between the supply and demand of CES.

The Aryl Sulfide Synthesis via Sulfide Transfer.

Aryl sulfides are in great demands in drugs and materials sciences. To avoid using nucleophilic and noxious thiols, many efforts have been focused on exploring novel sulfide resources. Herein, a reductive Pd-catalyzed, Ni-mediated method to synthesize aryl sulfides via a sulfide transfer reaction is developed. The utility and scope of this reaction is exemplified by various aryl electrophiles and aryl sulfides. Mechanistic studies reveal two competing catalytic cycles of sulfide transfer and aryl transfer in this reaction, where the former one is favored over the later one because of the large energy barrier difference during the transmetalation. Moreover, two important chemicals are late-stage functionalized by this method, exhibiting the potential applications in drugs and materials science.

Efficient room temperature catalytic synthesis of alternating conjugated copolymers via C-S bond activation.

Structural defects in conjugated copolymers are severely detrimental to the optoelectronic properties and the performance of the resulting electronic devices fabricated from them. Therefore, the much-desired precision synthesis of conjugated copolymers with highly regular repeat units is important, but presents a significant challenge to synthetic materials chemists. To this end, aryl sulfides are naturally abundant substances and offer unrealized potential in cross-coupling reactions. Here we report an efficient room temperature polycondensation protocol which implements aryl disulfide C-S activation to produce defect-minimized semiconducting conjugated copolymers with broad scope and applicability. Thus, a broad series of arylstannanes and thioethers are employed via the present protocol to afford copolymers with number-average molecular weights (Mns) of 10.0-45.0 kDa. MALDI and NMR analysis of selected copolymers reveals minimal structural defects. Moreover, the polymer trap density here is smaller and the field effect mobility higher than that in the analogous polymer synthesized through thermal-activation Stille coupling.

Defect-Free Alternating Conjugated Polymers Enabled by Room- Temperature Stille Polymerization.

The Stille cross-coupling polymerization is one of the most efficient synthetic methods for donor-acceptor (D-A) type π-conjugated polymers (CPs). Nevertheless, thermal-activation Stille polymerization readily produced homocoupling defects, resulting in batch-to-batch variations in copolymers quality and deteriorating the device performance of electronics and optoelectronics. Here, a room-temperature Stille-type polymerization was developed, the utility and generality of which were demonstrated by synthesis of twelve D-A CPs with high molecular weights. Importantly, the resultant copolymers possessed no homocoupling (hc) structural defects, while hc reactions were observed in the thermal-activation Stille reactions. Thus, the organic field-effect transistors (OFETs) based on the former exhibited twofold higher charge transport mobility (2.10 cm2  V-1 s-1 ), since it possessed stronger crystallinity and lower trap density of states (tDOS).

Achieving Efficient NIR-II Type-I Photosensitizers for Photodynamic/Photothermal Therapy upon Regulating Chalcogen Elements.

Second near-infrared (NIR-II) window type-I photosensitizers have intrinsic advantages in photodynamic/photothermal therapy (PDT/PTT) of some malignant tumors with deep infiltration, large size, complicated location, and low possibility of surgery/radiotherapy. Herein, three chalcogen-element-based donor-acceptor-type semiconducting polymers (poly[2,2″-((E)-4,4″-bis(2-octyldodecyl)-[6,6″-bithieno[3,2-b]pyrrolylidene]-5,5″(4H,4″H)-dione)-alt-2,5-(thiophene)] (PTS), poly[2,2″-((E)-4,4″-bis(2-octyldodecyl)-[6,6″-bithieno[3,2-b]pyrrolylidene]-5,5″(4H,4″H)-dione)-alt-2,5-(selenophene)] (PTSe), and poly[2,2″-((E)-4,4″-bis(2-octyldodecyl)-[6,6″-bithieno[3,2-b]pyrrolylidene]-5,5″(4H,4'H)-dione)-alt-2,5-(tellurophene)] (PTTe)) are synthesized and fully characterized, demonstrating strong absorption in the NIR-II region. Upon adjusting the chalcogen elements, the intramolecular charge-transfer characteristics and the heavy-atom effect are tuned to enhance the intersystem crossing rate, improving the photodynamic effect. Moreover, the energy levels and Gibbs free energies are tuned to facilitate the type-I photodynamic process. As a result, PTTe nanoparticles (NPs) produce superoxide anion radicals (O2 •- ) more efficiently and demonstrate higher photothermal conversion efficiency than PTS and PTSe NPs upon NIR-II (1064 nm) laser irradiation, exhibiting unprecedented NIR-II type-I PDT/PTT performance in vitro and in vivo. This work provides ideas for achieving high-performance NIR-II type-I PDT/PTT semiconducting polymers for hypoxic oncotherapy.

The impact of individual capabilities on the access to ecosystem services: a case study from the Loess Plateau, China.

Exploring how people access ecosystem services and revealing the individual capabilities that affect the accessibility of ecosystem services are important for obtaining a clear understanding of the contribution of ecosystem services to human well-being. Previous studies on ecosystem services have incorporated too little empirical research on the accessibility of ecosystem services and on the individual capabilities that affect accessibility. We chose the ecologically fragile and economically underdeveloped Loess Plateau as the research area because local farmers in this area are dependent on ecosystem services. The importance and accessibility of ecosystem services were evaluated on the basis of questionnaire surveys and semistructured interviews. The results showed that crops, meat, and water yield were the most important ecosystem services but were the most difficult to access. In contrast, fruit and soil fertility were easier to access. Furthermore, we determined the individual capabilities of local farmers based on Nussbaum's capabilities list as well as the actual conditions for local farmers and explored the impact of individual capabilities on the accessibility of ecosystem services. The results showed that local ecological knowledge and the ability to socialize were the key individual capabilities determining whether local farmers can access ecosystem services. Compared with farmers who have a formal education, farmers with rich local ecological knowledge can more easily access to crops and erosion control. The ability to socialize reflects the exchanges or donations of ecosystem services among farmers, which increase the accessibility of fodder and organic fertilizer. Physical health, financial capital, and other individual capabilities also have an impact on the accessibility of certain ecosystem services. Therefore, improving these individual capabilities is of great value for improving farmers' well-being. In policy-making and community management, the government needs to consider the development of farmers' individual capabilities in addition to considering poverty alleviation measures.

Research on Mediating Mechanisms and the Impact on Food Provision Services in Poor Areas from the Perspective of Stakeholders.

Exploring and analyzing the common demands and behavioral responses of different stakeholders is important for revealing the mediating mechanisms of ecosystem service (ES) and realizing the management and sustainable supply of ES. This study took Mizhi County, a poverty-stricken area on the Loess Plateau in China, as an example. First, the main stakeholders, common demands, and behavioral responses in the food provision services were identified. Second, the relationship among stakeholders was analyzed. Finally, this study summarized three types of mediating mechanisms of food provision services and analyzed the influence of the different types of mediating mechanisms. The main conclusions are as follows: (1) Five main stakeholders in the study area were identified: government, farmers, enterprises, cooperatives, and middlemen. (2) Increasing farmers' income is the common demand of most stakeholders in the study area, and this common demand has different effects on the behavioral responses of different stakeholders. (3) There are three types of mediating mechanisms in the study area: government + farmers mediating corn and mutton, government + enterprises mediating millet, and government + cooperatives mediating apples. On this basis, the effects of the different types of mediating mechanisms on variations in food yield, and trade-offs and synergies in typical townships, were analyzed.

Synthetic Routes for Heteroatom-Containing Alkylated/Arylated Polycyclic Aromatic Hydrocarbons.

Synthetic routes for heteroatom-containing polycyclic aromatic hydrocarbons (H-PAHs) with alkyl and aryl substitution are demonstrated. Three H-PAHs, including heteroatom-containing rubicenes (H-rubicenes), angular-benzothiophenes (ABTs), and indenothiophene (IDTs) were successfully synthesized by two key steps, including polysubstituted olefin formation and cyclization. Specifically, ABT and H-rubicenes were comprehensively investigated by single-crystal X-ray diffraction, NMR spectroscopy, UV-vis absorption, cyclic voltammetry, transient absorption, and single-crystal OFET measurements.

Precisely Tuning Photothermal and Photodynamic Effects of Polymeric Nanoparticles by Controlled Copolymerization.

Cancer possesses normoxic and hypoxia microenvironments with different levels of oxygen, needing different efficacies of photothermal and photodynamic therapies. It is important to precisely tune the photothermal and photodynamic effects of phototherapy nano-agents for efficient cancer treatment. Now, a series of copolymeric nanoparticles (PPy-Te NPs) were synthesized in situ by controlled oxidative copolymerization with different ratios of pyrrole to tellurophene by FeCl3 . The photothermal and photodynamic effects of semiconducting nano-agents under the first near-infrared (NIR) irradiation were precisely and systematically tuned upon simply varying the molar ratio of the pyrrole to tellurophene. The PPy-Te NPs were used for cancer treatment in mice, exhibiting excellent biocompatibility and therapeutic effect. This work presents a simple method to tune photothermal and photodynamic therapies effect in semiconducting nano-agents for cancer treatment.

Perylene Diimide-Based Conjugated Polymers for All-Polymer Solar Cells.

In recent decades, non-fullerene acceptors (NFAs) are undergoing rapid development and emerging as a hot area in the field of organic solar cells. Among the high-performance non-fullerene acceptors, aromatic diimide-based electron acceptors remain to be highly promising systems. This review discusses the important progress of perylene diimide (PDI)-based polymers as non-fullerene acceptors in all-polymer solar cells (all-PSCs) since 2014. The relationship between structure and property, matching aspects between donors and acceptors, and device fabrications are unveiled from a synthetic chemist perspective.

Evolutionary Characteristics and Trade-Offs' Development of Social-Ecological Production Landscapes in the Loess Plateau Region from a Resilience Point of View: A Case Study in Mizhi County, China.

Social-ecological production landscape resilience (SELPR) is a significant representation of the continuous supply capacity of landscape services. It is a quantitative assessment of the spatial-temporal evolution of SELPR under internal and external disturbances that provides a scientific basis for regional ecological environments and socio-economic development. Taking Mizhi County for the study of the Loess Plateau region, a three-dimensional (social system, ecosystem, and production system) SELPR evaluation framework was constructed. Data integration was performed using the watershed as the evaluation unit. This study quantitatively evaluated the spatial-temporal differentiation of the social-ecological production landscape (SELPs) subsystem's resilience and the total SELPR in the study area and classified the areas from the three-system resilience combination level to achieve regional development trade-offs. The results were as follows: (1) In 2009-2018, the change in the social-ecological production landscapes pattern in Mizhi County showed a significant reduction in agricultural production landscapes, relatively stable social living landscapes, and an increase in ecological landscapes; (2) in 2009-2018, the SELPR increased by 12.38%. The spatial distribution of resilience was significantly different, showing a distribution pattern of high central and low surrounding areas; (3) the county's watershed development zones were divided into five partitions: synergistic promotion areas, ecological restoration areas, social development areas, production optimization areas, and comprehensive remediation areas. The five types of zones have a certain agglomeration effect. In addition, the main obstacle factors affecting the SELPR of each zone are quite different. The key issues and development directions of different types of watersheds are also proposed in this paper.

Exploring the linkage between the supply and demand of cultural ecosystem services in Loess Plateau, China: a case study from Shigou Township.

Including cultural ecosystem services (ES) in the management of an ecosystem can improve the social acceptance and legitimacy of management decisions. In order to adapt to the inherently fragile ecological environment, the Loess Plateau has formed a unique land-use mode and rural cultural landscape, yet the research on the cultural ES in this area is limited. The study of cultural ES from the supply and demand perspective will contribute to realize the sustainable cultural ES supply and meet people's growing demand for a better life. This study conducted a questionnaire survey with 381 people in 42 villages of Shigou Township in the Loess Plateau to explore local residents' demand (perceived importance) of 8 types of cultural ES. The 5-point Likert scale was used to quantify the relative level of residents' demand of cultural ES. Spearman's rank correlation analysis was used to evaluate the correlations between pairs of cultural ES. In addition, this study constructed the indicator system of cultural ES supply from two dimensions of cultural ES supply capacity and accessibility and used a redundancy analysis to explore the linkage between the cultural ES supply and demand. The results showed that residents had a higher demand for esthetics and sense of place, but lower demand for spiritual and religious in Shigou Township. There were significant and positive correlations between different types of cultural ES, and most of them were enjoyed in "bundles." Each type of cultural ES was related to different types of percentage land cover, and geographical distance played an important role in cultural ES supply. Last, we proposed that local residents' perceived importance of cultural ES should be included in decision-making to improve public support for ecosystem management, and managers should simultaneously pay attention to the supply capacity and accessibility of cultural ES to realize the sustainable cultural ES supply.