An Azulene-Based Crystalline Porous Covalent Organic Framework for Efficient Photothermal Conversion.

The designed synthesis of a crystalline azulene-based covalent organic framework (COF-Azu-TP) is presented and its photothermal property is investigated. Azulene, a distinctive 5-7 fused ring non-benzenoid aromatic compound with a large intramolecular dipole moment and unique photophysical characteristics, is introduced as the key feature in COF-Azu-TP. The incorporation of azulene moiety imparts COF-Azu-TP with broad-spectrum light absorption capability and interlayer dipole interactions, which makes COF-Azu-TP a highly efficient photothermal conversion material. Its polyurethane (PU) composite exhibits a solar-to-vapor conversion efficiency (97.2%) and displays a water evaporation rate (1.43 kg m-2 h-1) under one sun irradiation, even at a very low dosage of COF-Azu-TP (2.2 wt%). Furthermore, COF-Azu-TP is utilized as a filler in a polylactic acid (PLA)/polycaprolactone (PCL) composited shape memory material, enabling rapid shape recovery under laser stimulation. A comparison study with a naphthalene-based COF isomer further emphasizes the crucial role of azulene in enhancing photothermal conversion efficiency. This study demonstrates the significance of incorporating specific building blocks into COFs for the development of functional porous materials with enhanced properties, paving the way for future applications in diverse fields.

Interaction between Extreme Temperature Events and Fine Particulate Matter on Cardiometabolic Multimorbidity: Evidence from Four National Cohort Studies.

Accumulating evidence linked extreme temperature events (ETEs) and fine particulate matter (PM2.5) to cardiometabolic multimorbidity (CMM); however, it remained unknown if and how ETEs and PM2.5 interact to trigger CMM occurrence. Merging four Chinese national cohorts with 64,140 free-CMM adults, we provided strong evidence among ETEs, PM2.5 exposure, and CMM occurrence. Performing Cox hazards regression models along with additive interaction analyses, we found that the hazards ratio (HRs) of CMM occurrence associated with heatwave and cold spell were 1.006-1.019 and 1.063-1.091, respectively. Each 10 µg/m3 increment of PM2.5 concentration was associated with 17.9% (95% confidence interval: 13.9-22.0%) increased risk of CMM. Similar adverse effects were also found among PM2.5 constituents of nitrate, organic matter, sulfate, ammonium, and black carbon. We observed a synergetic interaction of heatwave and PM2.5 pollution on CMM occurrence with relative excess risk due to the interaction of 0.999 (0.663-1.334). Our study provides novel evidence that both ETEs and PM2.5 exposure were positively associated with CMM occurrence, and the heatwave interacts synergistically with PM2.5 to trigger CMM.

Cohort profile: China undergraduate cohort for environmental health study.

The China Undergraduate Cohort (CUC) is an ambispective cohort study with its major purpose to better understand the effects of lifetime environmental exposures on health outcomes. We recruited 5322 college students with an average age of 18.3 ± 0.7 years in China from August 23, 2019 to October 28, 2019. Follow-up surveys were conducted annually. The dataset comprises individual demographic data (e.g. age, sex, height, weight, birth date, race, home address, annual family income, contact information), health-related behavior data (smoking status, smoking cessation, passive smoking exposure, drinking habit, physical activity, dietary status), lifestyle data (physical exercise, dietary habit, length of time spent outdoors), disease history (respiratory disease history, cardiovascular disease history, urinary system disease history, etc.), mental health status data (sleep quality, self-reported stress, anxiety and depression symptoms), lung function and blood samples data. Preliminary results from our cohort have found the association between air pollution, summer heat and mercury exposure and lung function among young adults in China.

Ambient ozone pollution impairs glucose homeostasis and contributes to renal function decline: Population-based evidence.

Particulate matter pollution could increase the risk of kidney disease, while evidence for ozone exposure is less well-established. Here, we aimed to evaluate the effect of ozone pollution on renal function and explore mechanisms. We first conducted a cross-sectional study based on Wuhan Chronic Disease Cohort Study baseline information. We recruited 2699 eligible participants, estimated their residential ozone concentrations, collected fasting peripheral blood samples for biochemical analysis and calculated the estimated glomerular filtration rate (eGFR). The linear regression model was applied to evaluate the long-term association between ozone pollution and eGFR. Then, we recruited another 70 volunteers as a panel with 8 rounds follow-up visits. We calculated the eGFR and measured fasting blood glucose and lipid levels. The linear mixed-effect model along with mediation analysis were performed to confirm the short-term association and explore potential mechanisms, respectively. For the long-term association, a 10.95 µg/m3 increment of 3-year ozone exposure was associated with 2.96 mL/min/1.73 m2 decrease in eGFR (95%CI: -4.85, -1.06). Furthermore, the drinkers exhibited a pronounced declination of eGFR (-7.46 mL/min/1.73 m2, 95%CI: -11.84, -3.08) compared to non-drinkers in relation to ozone exposure. Additionally, a 19.02 µg/m3 increase in 3-day ozone concentrations was related to 2.51 mL/min/1.73 m2 decrease in eGFR (95%CI: -3.78, -1.26). Hyperglycemia and insulin resistance mediated 12.2% and 16.5% of the aforementioned association, respectively. Our findings indicated that higher ozone pollution could affect renal function, and the hyperglycemia and insulin resistance linked to ozone might be the underlying mechanisms.

Mechanism Behind the Programmed Biosynthesis of Heterotrimeric Fungal Depside Thielavin A.

Thielavin A (1) is a fungal depside composed of one 3-methylorsellinic acid and two 3,5-dimethylorsellinic acid units. It displays diverse biological activities. However, the mechanism underlying the assembly of the heterotrimeric structure of 1 remains to be clarified. In this study, we identified the polyketide synthase (PKS) involved in the biosynthesis of 1. This PKS, designated as ThiA, possesses an unusual domain organization with the C-methyltransferase (MT) domain situated at the C-terminus following the thioesterase (TE) domain. Our findings indicated that the TE domain is solely responsible for two rounds of ester bond formation, along with subsequent chain hydrolysis. We identified a plausible mechanism for TE-catalyzed reactions and obtained insights into how a single PKS can selectively yield a specific heterotrimeric product. In particular, the tandem acyl carrier protein domains of ThiA are critical for programmed methylation by the MT domain. Overall, this study highlighted the occurrence of highly optimized domain-domain communication within ThiA for the selective synthesis of 1, which can advance our understanding of the programming rules of fungal PKSs.

Ketoreductase Domain-Catalyzed Polyketide Chain Release in Fungal Alkyl Salicylaldehyde Biosynthesis.

Alkyl salicylaldehyde derivatives are polyketide natural products, which are widely distributed in fungi and exhibit great structural diversity. Their biosynthetic mechanisms have recently been intensively studied; however, how the polyketide synthases (PKSs) involved in the fungal alkyl salicylaldehyde biosyntheses release their products remained elusive. In this study, we discovered an orphan biosynthetic gene cluster of salicylaldehyde derivatives in the fungus Stachybotrys sp. g12. Intriguingly, the highly reducing PKS StrA, encoded by the gene cluster, performs a reductive polyketide chain release, although it lacks a C-terminal reductase domain, which is typically required for such a reductive release. Our study revealed that the chain release is achieved by the ketoreductase (KR) domain of StrA, which also conducts cannonical ß-keto reductions during polyketide chain elongation. Furthermore, we found that the cupin domain-containing protein StrC plays a critical role in the aromatization reaction. Collectively, we have provided an unprecedented example of a KR domain-catalyzed polyketide chain release and a clearer image of how the salicylaldehyde scaffold is generated in fungi.

Integrated analysis of intratumoral biomarker and tumor-associated macrophage to improve the prognosis prediction in cancer patients.

BACKGROUND: The lack of effective and accurate predictive indicators remains a major bottleneck for the improvement of the prognosis of patients with hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC). Hepatitis B virus X (HBx) has been widely suggested as a critical pathogenic protein for HBV-driven liver carcinogenesis, while tumor-associated macrophage (TAM) infiltration is also closely related to the tumorigenesis and progression of HCC. However, few studies have determined whether combining HBx expression with TAM populations could increase the accuracy of prognostic prediction for HBV-related HCC. METHODS: The study cohort enrolling 251 patients with HBV-related HCC was randomly split into a training and a validation group (ratio 1:1). The expression levels of HBx and TAM marker CD68 in HCC samples were detected by immunohistochemistry. Kaplan-Meier curves, Cox regression and Harrell's concordance index (C-index) analysis were conducted to evaluate the prognostic significance of these indicators alone or in combination. RESULTS: The expression level of HBx was strongly correlated with CD68+ TAM infiltration in HCC tissues. Elevated HBx or CD68 expression indicated poorer overall survival (OS) and progression-free survival (PFS) after hepatectomy, and both of them were independent risk factors for postoperative survival. Meanwhile, patients with both high HBx and CD68 levels had worst clinical outcomes. Moreover, integrating HBx and CD68 expression with clinical indicators (tumor size and micro-vascular invasion) showed the best prognostic potential with highest C-index value for survival predictivity, and this proposed model also performed better than several conventional classifications of HCC. CONCLUSION: Combining the expression of intratumoral HBx, CD68+ TAM population and clinical variables could enable better prognostication for HBV-related HCC after hepatectomy, thus providing novel insights into developing more effective clinical prediction model based on both molecular phenotypes and tumor-immune microenvironment.

Photocatalyzed Defluorinative Dichloromethylation of α-CF3 Alkenes Using CHCl3 as the Radical Source.

A visible-light-induced defluorinative dichloromethylation of α-CF3 alkenes was developed with cheap and readily accessible chloroform simultaneously as a dichloromethylation reagent and reaction medium, leading to the facile preparation of new polyhalogenated scaffolds. Notably, the change from CHCl3 to CDCl3 offers a straightforward pathway for accessing the deuterated analogues with excellent degrees of D incorporation. Mechanistic studies suggested the reaction underwent a radical addition of the dichloromethyl radical with alkenes, followed by sequential single-electron transfer and defluorination. This protocol features mild conditions, easy operation, facile scalability, and high efficiency, allowing convenient access to dichloronated gem-difluoroalkenes.

Inverse association of glucosamine use and risk of new-onset kidney stones in UK adults with less sedentary time.

OBJECTIVE: To assess the association of different sedentary behaviors and glucosamine use with the risk of kidney stones and examine the modification of genetic risk of kidney stones on this association. METHODS: 473,225 participants free of kidney stones at baseline from the UK Biobank were included. Total sedentary time was calculated as the sum of the duration of TV-watching, driving, and non-occupational computer using. The primary outcome was new-onset kidney stones. RESULTS: During a median follow-up of 12.0 years, 5528 cases of kidney stones were documented. All major sedentary behaviors and total sedentary time were significantly positively related to the risk of kidney stones (All P for trend<0.05). Participants with total sedentary time ≥ 3.5 h/day had a significantly higher risk of new-onset kidney stones (vs. <3.5 h/day [tertile 1]; HR, 1.18; 95%CI,1.10-1.27). Compared with non-users, participants who regularly used glucosamine had a significantly lower risk of new-onset kidney stones in those with total sedentary time < 3.5 h/day (HR, 0.72; 95%CI,0.59-0.86), but not in those with total sedentary time ≥ 3.5 h/day (HR, 0.99; 95%CI,0.91-1.08; P-interaction = 0.001). Among participants with total sedentary time < 3.5 h/day, there was a dose-response relationship of glucosamine use with new-onset kidney stones (P for trend<0.001). Genetic risks of kidney stones did not significantly modify the association. CONCLUSIONS: TV-watching, driving and non-occupational computer using were all positively associated with the risk of new-onset kidney stones. Glucosamine use was associated with a lower risk of new-onset kidney stones in participants with total sedentary time < 3.5 h/day, following a dose-response relationship.

Associations of fine particulate matter and its metal constituents with blood pressure: A panel study during the seventh World Military Games.

Evidence is needed to elucidate the association of blood pressure (BP) changes with metal constituents in fine particulate matter (PM2.5). Therefore, we designed a longitudinal panel study enrolling 70 healthy students from Wuhan University in the context of the seventh World Military Games (the 7th WMG) from September 2019 to January 2020. A total of eight visits were conducted before, during, and after the 7th WMG. During every visit, each participant was asked to carry a personal PM2.5 monitor to measure hourly PM2.5 levels for three consecutive days. Questionnaire investigation and physical examination were completed on the fourth day. We analyzed ten metal constituents of ambient PM2.5 collected from the fixed station, and blood pressure was recorded during each visit. The linear mixed-effects models were performed to evaluate associations of metal constituents and blood pressure measurements. We observed a dramatic variation of PM2.5 concentration ranging from 7.38 to 132.04 µg/m3. A 10 µg/m3 increment of PM2.5 was associated with an increase of 0.64 mmHg (95% CI: 0.44, 0.84) in systolic BP (SBP), 0.40 mmHg (0.26, 0.54) in diastolic BP (DBP), 0.31 mmHg (0.15, 0.47) in pulse pressure (PP) and 0.44 mmHg (0.26, 0.62) in mean artery pressure (MAP), respectively. For metal constituents in PM2.5, robust positive associations were observed between BP and selenium, manganese, arsenic, cadmium, and thallium. For example, for an IQR (0.93 ng/m3) increment of selenium, SBP and MAP elevated by 0.98 mmHg (0.09, 1.87) and 0.71 mmHg (0.03, 1.39), respectively. Aluminum was found to be robustly associated with decreased SBP, DBP, and MAP. The study indicated that exposure to PM2.5 total mass and metal constituents including selenium, manganese, arsenic, cadmium, and thallium were associated with the elevated BP.

Independent and interactive associations between greenness and ambient pollutants on novel glycolipid metabolism biomarkers: A national repeated measurement study.

This study aims to investigate the independent and interactive effects of greenness and ambient pollutants on novel glycolipid metabolism biomarkers. A repeated national cohort study was conducted among 5085 adults from 150 counties/districts across China, with levels of novel glycolipid metabolism biomarkers of TyG index, TG/HDL-c, TC/HDL-c, and non-HDL-c measured. Exposure levels of greenness and ambient pollutants (including PM1, PM2.5, PM10, and NO2) for each participant were determined based on their residential location. Linear mixed-effect and interactive models were used to evaluate the independent and interactive effects between greenness and ambient pollutants on the four novel glycolipid metabolism biomarkers. In the main models, the changes [ß (95% CIs)] of TyG index, TG/HDL-c, TC/HDL-c, and non-HDL-c were -0.021 (-0.036, -0.007), -0.120 (-0.175, -0.066), -0.092 (-0.122, -0.062), and -0.445 (-1.370, 0.480) for every 0.1 increase in NDVI, and were 0.004 (0.003, 0.005), 0.014 (0.009, 0.019), 0.009 (0.006, 0.011), and 0.067 (-0.019, 0.154) for every 1 µg/m3 increase in PM1. Results of interactive analyses demonstrated that individuals living in low-polluted areas could get greater benefits from greenness than those living in highly-polluted areas. Additionally, the results of mediation analyses revealed that PM2.5 mediated 14.40% of the association between greenness and the TyG index. Further research is needed to validate our findings.

Effects of air pollution and residential greenness on sleep disorder: A 8-year nationwide cohort study.

BACKGROUND: Sleep disorder influencing the quality of life, however, its contributing factors have not been fully identified yet. Recently the potential effects of environmental exposures like air pollution and greenness on sleep disorder have attracted attention, but the evidence in China is limited, particularly in the middle-aged and elderly. METHODS: We conducted a nationwide prospective study that included 21,878 Chinese citizens aged 45 years or above. For each participant, the 3-year averaged exposure concentrations of air pollutants (including PM10, PM2.5, PM1, NO2) and greenness (assessed by NDVI) were estimated based on residential address. We used mixed-effects logistic models to examine the associations of sustained air pollutants and greenness exposures with the occurrence of sleep disorder, and used linear mixed-effects models to assess the associations with sleep duration. Specifically, interaction effects models were employed to identify potential modificators of the above associations. RESULTS: A total of 39,580 survey responses were received, with the overall occurrence rate of sleep disorder was 25.7%. A 10 µg/m3 increment in PM10 and PM2.5 were associated with increased occurrence of sleep disorder at 2% (aOR = 1.02, 95%CI:1.01, 1.04) and 7% (aOR = 1.07, 95%CI: 1.04, 1.11), and were associated with reduced sleep duration by 0.07 (95% CI: 0.08, 0.05) and 0.04 (95% CI: 0.05, 0.03) hours, respectively. Residential greenness appears to the potential protective factor for sleep disorder, that a 0.1 higher of the NDVI was associated a 9% (aOR = 0.91, 95%CI: 0.86, 0.96) decreased occurrence of sleep disorder and 0.09 h (95% CI: 0.05, 0.13) longer of sleep duration. Age and residence were identified as modificators of the above significant associations. CONCLUSION: Sustained exposure to air pollutants can increase the occurrence of sleep disorder and can reduce sleep duration, while exposure to higher levels of greenness can protect sleep health from the side effects of air pollutants.

Exposures to ambient air pollutants increase prevalence of sleep disorder in adults: Evidence from Wuhan Chronic Disease Cohort Study (WCDCS).

BACKGROUND: Sleep disorder contributes to memory dysfunction and chronic diseases. Clear evidence of environment disturbance, such as residential noise, are associated with an increased risk of sleep disorder. However, not enough studies have been conducted on association between residential air pollutants and sleep disorder. We sought to determine whether exposures to residential air pollutants associated with risk of sleep disorder among adults. METHODS: Using the dataset of the Wuhan Chronic Disease Cohort Study (WCDCS), we investigated the prevalence of sleep disorder and five sleep disorder symptoms in the study. The data of air pollutants (including PM10, PM2.5, NO2, SO2 and O3) were obtained from 10 air quality monitoring stations in Wuhan. We utilized logistic regression model to evaluate the associations of five types of air pollutants with odds ratio (OR) of sleep disorder and symptoms. The potential moderating effects of socio-demographic factors in the associations were explored using the interaction effects model. RESULTS: Of the study participants, 52.1 % had sleep disorder. Exposures to higher concentrations of air pollutants were associated with increased prevalence of sleep disorder. For example, per interquartile range (IQR) increases in concentrations of PM10, PM2.5 or SO2 corresponded to the increase of sleep disorder increased prevalence at 14.7 % (adjusted odds ratio (aOR) = 1.147, 95 %CI:1.062, 1.240), 8.9 % (aOR = 1.089, 95 %CI: 1.003, 1.182) and 15.8 % (aOR = 1.158, 95 %CI: 1.065, 1.260). For symptoms specific analyses, significant linkages of PM10, PM2.5, SO2 with difficulty in falling asleep, wake up after falling asleep and early awaken were observed. Moderating effects of age and place of residence on the linkages of PM10 with increased prevalence of sleep disorder were identified. CONCLUSION: Higher level of air pollution exposure could increase the prevalence of sleep disorder. Middle-aged and elderly population, as well as the rural residents are more likely to suffer from sleep disorder.

Probabilistic Semantic Mapping for Autonomous Driving in Urban Environments.

Statistical learning techniques and increased computational power have facilitated the development of self-driving car technology. However, a limiting factor has been the high expense of scaling and maintaining high-definition (HD) maps. These maps are a crucial backbone for many approaches to self-driving technology. In response to this challenge, we present an approach that fuses pre-built point cloud map data with images to automatically and accurately identify static landmarks such as roads, sidewalks, and crosswalks. Our pipeline utilizes semantic segmentation of 2D images, associates semantic labels with points in point cloud maps to pinpoint locations in the physical world, and employs a confusion matrix formulation to generate a probabilistic bird's-eye view semantic map from semantic point clouds. The approach has been tested in an urban area with different segmentation networks to generate a semantic map with road features. The resulting map provides a rich context of the environment that is valuable for downstream tasks such as trajectory generation and intent prediction. Moreover, it has the potential to be extended to the automatic generation of HD maps for semantic features. The entire software pipeline is implemented in the robot operating system (ROS), a widely used robotics framework, and made available.

Conditional Generative Models for Dynamic Trajectory Generation and Urban Driving.

This work explores methodologies for dynamic trajectory generation for urban driving environments by utilizing coarse global plan representations. In contrast to state-of-the-art architectures for autonomous driving that often leverage lane-level high-definition (HD) maps, we focus on minimizing required map priors that are needed to navigate in dynamic environments that may change over time. To incorporate high-level instructions (i.e., turn right vs. turn left at intersections), we compare various representations provided by lightweight and open-source OpenStreetMaps (OSM) and formulate a conditional generative model strategy to explicitly capture the multimodal characteristics of urban driving. To evaluate the performance of the models introduced, a data collection phase is performed using multiple full-scale vehicles with ground truth labels. Our results show potential use cases in dynamic urban driving scenarios with real-time constraints. The dataset is released publicly as part of this work in combination with code and benchmarks.

Association between long-term exposure to ambient particulate matter and blood pressure, hypertension: an updated systematic review and meta-analysis.

Evidence of more recent studies should be updated to evaluate the effect of long-term exposure to particulate matter (PM) on blood pressure and hypertension.        Studies of long-term effects of PM1, PM2.5 and PM10 on blood pressure (SBP, DBP, MAP), hypertension were searched in Pubmed, Web of Science and Embase before May, 2021. Meta-analysis of 41 studies showed that exposure to PM1, PM2.5 was associated with SBP (1.76 mmHg (95%CI:0.71, 2.80) and 0.63 mmHg (95%CI:0.40, 0.85), per 10 µg/m3 increase in PM), all three air pollutants (PM1, PM2.5, PM10) was associated with DBP (1.16 mmHg (95%CI:0.34, 1.99), 0.31 mmHg (95%CI:0.16, 0.47), 1.17 mmHg (95%CI:0.24, 2.09), respectively. As for hypertension, PM1, PM2.5 and PM10 were all significantly associated with higher risk of hypertension (OR=1.27 (95%CI:1.06, 1.52), 1.15 (95%CI:1.10, 1.20) and 1.11 (95%CI:1.07, 1.16). In conclusion, our study indicated a positive association between long-term exposure to particulate matter and increased blood pressure, hypertension.

A Facile, Efficient, and General Synthetic Method to Amide-Linked Covalent Organic Frameworks.

Amide-linked covalent organic frameworks (amide COFs) possess enormous potentials in practical applications benefiting from their high stability and polyamide structures. However, they suffer from very limited accessibility. Herein, we report a new linkage conversion method to rapidly synthesize crystalline amide COFs through oxidation of imine linkages in their corresponding imine-linked frameworks with KHSO5 as an oxidant under very mild conditions. This synthetic strategy is general, facile, efficient, and scalable, as demonstrated by the procedure of simply stirring mixtures of imine-linked COFs (seven examples) and KHSO5 in anhydrous dimethylformamide for several hours to complete the conversions and gram-scale synthesis. The high efficiency of this approach enables facile production of amide COFs from widely available imine-linked COFs, which lays the foundation for exploring practical applications of this unique type of polyamide material.

Photoredox-Catalyzed Cascade of o-Hydroxyarylenaminones to Access 3-Aminated Chromones.

Reported herein is a photoredox-catalyzed amination of o-hydroxyarylenaminones with tert-butyl ((perfluoropyridin-4-yl)oxy)carbamate, a versatile amidyl-radical precursor developed in our laboratory. This work establishes a new cascade pathway for the assembly of a range of 3-aminochromones under mild conditions. Downstream transformations of the obtained 3-aminochromones to construct diverse amino pyrimidines greatly broaden the applications of this photocatalyzed protocol.

Phosphine-Mediated Morita-Baylis-Hillman-Type/Wittig Cascade: Access to E-Configured 3-Styryl- and 3-(Benzopyrrole/furan-2-yl) Quinolinones.

A phosphine-mediated, well-designed Morita-Baylis-Hillman-type/Wittig cascade for the rapid assembly of a quinolinone framework from benzaldehyde derivatives is developed for the first time. By rationally combining I2/NIS-mediated cyclization, biologically relevant 3-(benzopyrrole/furan-2-yl) quinolinones were facilely synthesized in a one-pot process by starting from 3-styryl-quinolinones bearing an o-hydroxy/amino group, significantly expanding the chemical space of this privileged skeleton. Further utility of this protocol is illustrated by successfully performing this transformation in a catalytic manner through in situ reduction of phosphine oxide by phenylsilane.

Photoinduced Construction of a Benzothienopyridine-S,S-dioxide Framework Enabled by Polychloropyridyl Multifunctional Motifs.

Reported herein is a visible-light-induced, catalyst-free intramolecular cyclization of 4-phenylsulfonyl-2,3,5,6-tetrachloropyridine, leading to rapid assembly of a series of unprecedented benzo[4,5]thieno[3,2-c]pyridine 5,5-dioxide scaffolds under mild conditions. The rational introduction of a perchloropyridin-4-yl module significantly facilitated this photoinduced process and offers a versatile platform for broad structural variation. Mechanistic studies revealed that a newly identified charge-transfer complex with carbonate is crucial to this photoinduced process.