Exposure to OPFRs Is Associated with Obesity and Dysregulated Serum Lipid Profiles: Data from 2017-2018 NHANES.

Widespread exposure to organophosphorus flame retardants (OPFRs) has been observed in the general population. Emerging studies have revealed OPFRs possess endocrine-disturbing properties. The present study aims to assess the association between urinary metabolites of OPFRs, BMI, and serum lipid profiles. Data from the National Health and Nutrition Examination Survey (NHANES) 2017-2018 were obtained, with 1334 adults enrolled in the current study. Urinary concentrations of bis (1-chloro-2-propyl) phosphate (BCIPP), bis(2-chloroethyl) phosphate (BCEP), bis(1,3-dichloro-2-propyl) phosphate (BDCPP), dibutyl phosphate (DBUP), and diphenyl phosphate (DPHP) were quantified to assess OPFR exposure. Covariate-adjusted linear and logistic regression models were conducted to explore the associations between log2-transformed concentrations of OPFR metabolites, BMI, obesity, and serum lipid profiles. Stratified analyses were performed to assess the heterogeneity of associations by age, gender, race, etc. Positive associations were found between OPFR exposure and the risk of obesity. The multivariate linear analysis indicated that a one-unit increase in log2-transformed urinary concentrations of BCEP and BDCPP was associated with 0.27 (95% CI: 0.02-0.52, p = 0.0338) and 0.56 (95% CI: 0.25-0.87, p = 0.0004) higher BMI value, respectively. One log2-unit increase in urinary BCEP and BDCPP concentrations was associated with 1.1-fold (95% CI: 1.02-1.18, p = 0.0096) and 1.19-fold (95% CI: 1.09-1.30, p = 0.0001) risk for developing obesity. Furthermore, the non-linear relationship between exposure to OPFRs and obesity was identified. Additionally, multivariable linear regression showed that urinary DPHP concentrations were inversely correlated with serum triglyceride (TG) levels (ß = -7.41, 95% CI: -12.13 to -2.68, p = 0.0022). However, no other OPFR metabolites were found to be significantly statistically associated with serum lipid levels after adjusting for potential confounders. In conclusion, environmental exposure to OPFRs might contribute to obesity and dysregulated TG concentrations in adults. Future prospective research is warranted to confirm the causal relationship between metabolites of OPFRs and obesity.

Exposure to Perfluoroalkyl Substances and Hyperlipidemia Among Adults: Data From NHANES 2017-2018.

BACKGROUND: The present study aims to explore the relationship between perfluoroalkyl substances (PFAS) exposure and hyperlipidemia using data from the National Health and Nutrition Examination Survey. METHODS: A total of 1600 subjects were included in the analysis, and nine kinds of PFAS were measured. Multivariate logistic regression analysis was performed to explore the association between serum PFAS and hyperlipidemia. RESULTS: Compared with the lowest quartile of perfluoromethylheptane sulfonic acid isomers (Sm-PFOS), the percentage change for hyperlipidemia was 57% and 41% in the third and highest quartile of PFOS. The positive association between Sm-PFOS and hyperlipidemia remained significant in population younger than 60 years, and the odds ratio for hyperlipidemia in fourth quartile of Sm-PFOS was 1.81. CONCLUSIONS: These findings indicated that serum Sm-PFOS was independently associated with a higher risk for hyperlipidemia. The epidemiological study warrants further study to elucidate the causal relationship between them.

Occurrence, distribution, and risk assessment of pesticides in surface water and sediment in Jiangsu Province, China.

The occurrence and distribution of 157 pesticides were investigated in surface water and sediment in Jiangsu Province, China. Gas chromatography-mass spectrometry was used to analyze and quantify these pesticides, and the risk quotient method was used to evaluate their respective environmental risk. The results showed that 91 pesticides were detected in surface water. The organophosphates (OPPs), fungicides, and amide herbicides were predominant. The total concentration in surface water ranged from 63.7 to 22,463 ng/L, 3.90 to 7262 ng/L, and ND to 34,120 ng/L, respectively. The mean concentration was 3479 ng/L, 1644 ng/L, and 1878 ng/L, respectively. The concentration range of detected pesticides in the Yangtze River Basin was generally lower than that in the Huai River Basin. In sediment samples, a total of 63 pesticides were detected. OPPs and amide herbicides were also ranked highest; the total concentration in sediment samples ranged from 2951 to 47,739 ng/g and 106 to 12,996 ng/g, respectively. And the mean concentrations was 6971 ng/g and 5130 ng/g, respectively. Suqian City had the highest concentration for OPPs and amide herbicides in the Huai River Basin, followed by Huai'an City, while Nanjing City and Yangzhou City ranked highest in the Yangtze River Basin. The spatial distribution of pesticides in Jiangsu Province indicated a concentration significantly higher in the western and northern regions than in the eastern and southern regions, and a concentration generally higher in lakes than in rivers. The risk assessment results showed that OPPs, fungicides, amide herbicides, organochlorines, and triazine herbicides in most surface water samples posed a high risk and had regional pollution characteristics. In sediment samples, organochlorines, carbamates, other herbicides, and other insecticides posed a high risk in northern Jiangsu Province, whereas OPPs, amide herbicides, and triazine herbicides posed high risks everywhere in Jiangsu Province.

Occurrence and accumulation characteristics of legacy and novel brominated flame retardants in surface soil and river sediments from the downstream of Chuhe River basin, East China.

Surface soil and river sediment samples were collected from the downstream of Chuhe River basin, East China, to investigate the occurrence and accumulation characteristics of legacy and novel brominated flame retardants (NBFRs). The respective concentrations of BDE-209 and nine NBFRs ranged from n.d. to 41.4 ng/g dry weight (dw) and from 0.35 to 362.78 ng/g dw in the collected surface soil samples and ranged from 0.29 to 19.73 ng/g dw and from 0.70 to 66.83 ng/g dw in the collected river sediment samples. Soil samples exhibited a higher potential to accumulate BTBPE while the relative abundance of PBT in the collected sediment samples was significantly higher than that in soils. Even so, BTBPE was the predominant NBFR in both soil and sediment samples. The concentrations and relative abundances of legacy and NBFRs exhibited large spatial variation. The calculated concentration ratios of the total of the nine NBFRs (∑9NBFRs) to BDE-209 (∑9NBFRs/BDE-209) in most of the analyzed samples far exceeded 1, implying a clear shift from legacy brominated flame retardants to NBFRs in the downstream of Chuhe River basin.

Bifunctional catalytic degradation of diclofenac over Cu-Pd co-modified sponge iron-based trimetal: Parameter optimization.

Currently, the pharmaceutical and personal care products (PPCPs) have posed great challenge to advanced oxidation techniques (AOTs). In this study, we decorated sponge iron (s-Fe0) with Cu and Pd (s-Fe0-Cu-Pd) and further optimized the synthesis parameters with a response surface method (RSM) to rapidly degrade diclofenac sodium (DCF). Under the RSM-optimized conditions of Fe: Cu: Pd = 100: 4.23: 0.10, initial solution pH of 5.13, and input dosage of 38.8 g/L, 99% removal of DCF could be obtained after 60 min of reaction. Moreover, the morphological structure of trimetal was characterized with high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), X-ray diffraction (XRD), X-ray photoelectron spectra (XPS). Electron spin resonance (ESR) signals have also been applied to capture reactive hydrogen atoms (H*), superoxygen anions, hydroxyl radicals, and single state oxygen (1O2). Furthermore, the variations of DCF and its selective degradation products over a series of s-Fe0-based bi(tri)metals have been compared. Additionally, the degradation mechanism of DCF has also been explored. To our best knowledge, this is the first report revealing the selective dechlorination of DCF with low toxicity over Pd-Cu co-doped s-Fe0 trimetal.

Sex-specific effect of urinary metabolites of polycyclic aromatic hydrocarbons on thyroid profiles: results from NHANES 2011-2012.

The current study aims to evaluate the associations between 10 urinary polycyclic aromatic hydrocarbon (PAH) metabolites and thyroid profiles. The levels of 10 PAH metabolites and thyroid profiles were obtained from National Health and Nutrition Examination Survey (NHANES) 2011-2012. Spearman analysis was utilized to evaluate the correlation coefficients among these 10 PAH metabolites. Multivariate linear and logistic regression models assessed the relationship between urinary PAH metabolite levels, thyroid hormones, and thyroid autoantibodies after adjusting potential confounders. Stratified analysis by gender was performed to evaluate sex-specific effect of urinary metabolites of PAH on thyroid profiles. One thousand six hundred forty-five eligible adult participants with complete research data were enrolled. Of note, the concentrations of the majority of urinary PAH metabolites were remarkedly higher in females compared with males. 2-hydroxyfluorene (2-FLU) was associated with higher total triiodothyronine (T3) levels in whole population (ß = 2.113, 95% CI 0.339-3.888). In males, positive associations were observed in 1-hydroxynaphthalene (1-NAP) and free thyroxine (T4) (ß = 0.0002, 95% CI 0.0000-0.0004). 2-FLU was also found positively associated with total T3 (ß = 2.528, 95% CI 0.115-4.940) in male subjects. While in female participants, 2-hydroxynaphthalene (2-NAP) was associated with free T3 (ß = 0.002, 95% CI 0.000-0.005). 2-FLU was associated with total T3 (ß = 2.683, 95% CI 0.038-5.328), free T3 (ß = 0.050, 95% CI 0.012-0.087), and total T4 (ß = 0.195, 95% CI 0.008-0.382). 2-Hydroxyphenanthrene (2-OHP), 1-hydroxypyrene (1-HP), and 9-hydroxyfluorene (9-FLU) were all positively related to total T3 levels, and the corresponding coefficients were 16.504, 6.587, and 3.010. 9-FLU was also associated with free T3 (ß = 0.049, 95% CI 0.008-0.090). No statistical significances were found between PAH metabolite levels and increased prevalence of increased thyroglobulin antibody (TgAb)/thyroid peroxidase antibody (TPOAb) when PAH metabolites were treated as continuous variables. Meanwhile, in the quartile analyses, increased prevalence of elevated TgAb was observed in participants with quartile 2 2-NAP compared with lowest quartile (OR = 1.753, 95% CI 1.021-3.008). Male subgroup analyses indicated that increased prevalence of elevated TgAb was observed in higher quartile of 1-NAP, 2-NAP, and 3-hydroxyfluorene (3-FLU). Increased prevalence of elevated TPOAb was associated with higher 2-NAP quartile. However, in subgroup analysis of females, no statistical significances were found between PAH quartiles and increased TgAb/TPOAb. Significant correlations were found among these 10 PAH metabolites. In conclusion, the cross-sectional study indicated that exposure to PAH might disturb the concentrations of thyroid hormones and thyroid autoantibodies. It is noteworthy that significant differences existed in males and females. Further prospective research is warranted to explore the causal relationship and underlying mechanism of PAH exposure on thyroid dysfunction.

Association of blood cadmium and metabolic syndrome: a cross-sectional analysis of National Health and Nutrition Examination Survey 2017-2020.

Previous findings have reported the role of different types of heavy metals in cardiometabolic diseases. In the present research, we aim to evaluate the association between blood cadmium levels and Metabolic Syndrome (MetS) based on the large-sample NHANES data. Public availably data from NHANES 2017-2020 cycle was obtained. Participants were divided into MetS and non-MetS groups according to waist circumference (WC), triglyceride (TG), high-density lipoprotein (HDL), blood pressure (BP) and fasting plasma glucose (FPG) levels based on the National Cholesterol Education Program (NCEP) criteria. Student's t test, Mann-Whitney U test, and Chi-square test were performed for univariate analysis. Multivariate logistic analysis was performed to explore the relationship between blood cadmium and MetS and research findings were presented in forest plot. We also investigated the association of blood cadmium and MetS in subgroups stratified by age, gender and race. Population with MetS had significantly higher levels of blood [0.30 (0.18-0.54) vs. 0.24 (0.15-0.46) ug/L, p < 0.001] and urinary cadmium levels [0.29 (0.17-0.52) vs. 0.20 (0.09-0.42) ug/L, p < 0.001] compared with those without MetS. Higher blood cadmium concentrations were also observed in participants with elevated WC (0.28 vs. 023 ug/L, p < 0.001], TG (0.28 vs. 0.26 ug/L, p = 0.029), BP (0.33 vs. 0.23 ug/L, p < 0.001) and FPG (0.29 vs. 0.24 ug/L, p < 0.001) compared with those with normal metabolic parameters. Multivariate logistic regression showed that one-unit increasement of blood cadmium was associated with 1.25 times higher prevalence ratios for MetS after adjusting potential confounders (95% CI: 1.06-1.48, p = 0.0083). The associations between serum cadmium concentrations and MetS components were then evaluated, and the results showed higher blood cadmium levels were associated with higher risk for elevated TG, low HDL and elevated BP when treated as continuous variable. When treated as categorical variable, only BP was found positively associated with blood cadmium. Stratified multiple logistic regression analysis indicated that the positive association between blood cadmium and MetS remained significant in subjects less than 60 years old and female subgroup. In conclusion, the cross-sectional survey suggested the positive association between blood cadmium levels and risk for MetS, prospective research need to be conducted for further evaluation of the causal relationship between blood cadmium and MetS.

Association between aldehyde exposure and sex steroid hormones among adults.

Exogenous and endogenous exposure to aldehydes is seen worldwide. Aldehydes are closely associated with human diseases, especially reproductive toxicity. However, the effect of aldehyde exposure on sex steroid hormones among adults remains uninvestigated. A total of 851 participants aged over 18 years were included in this cross-sectional analysis based on data from National Health and Nutrition Examination Survey (NHANES) 2013-2014. Serum aldehyde concentrations were quantified following an automated analytical method. Sex steroid hormones including total testosterone, estradiol, and sex hormone binding globulin (SHBG) were detected. Multivariate linear regression models, forest plots, generalized additive model (GAM), and smooth curve fitting analysis were used to assess the associations between quartiles of aldehydes and sex steroid hormones levels after adjusting for potential confounders. Butyraldehyde and propanaldehyde were found to be negatively associated with estradiol and SHBG in females and males, respectively. ß values with 95% confidence intervals (95% CIs) were - 20.59 (- 38.30 to - 2.88) for Q2 vs. Q1 of butyraldehyde and - 8.13 (- 14.92 to - 1.33) and - 7.79 (- 14.91 to - 0.67) for Q2 vs. Q1 and Q4 vs. Q1 of propanaldehyde. No significant associations were observed between other aldehydes and sex hormones. In premenopausal women, isopentanaldehyde was inversely associated with serum total testosterone levels (Q4 vs. Q1: OR = - 7.95, 95% CI: - 15.62 to - 0.27), whereas propanaldehyde was positively associated with serum estradiol concentration (Q3 vs. Q1: ß = 28.88, 95% CI: 0.83 to 56.94). Compared with Q1, Q3 of isopentanaldehyde was associated with 3.53 pg/mL higher concentration of estradiol in postmenopausal women (ß = 3.53, 95% CI: 0.08 to 6.97). Moreover, in males under 40 years, butyraldehyde and heptanaldehyde were inversely proportional to total testosterone levels and heptanaldehyde and butyraldehyde were negatively associated with estradiol and SHBG. Decreased total testosterone, elevated estradiol, and decreased SHBG levels were found in higher quartiles of benzaldehyde, hexanaldehyde and isopentanaldehyde, and propanaldehyde, respectively, in males aged over 60 years. In male participants aged 40-60 years, only hexanaldehyde was observed to be correlated with higher serum estradiol levels. In conclusion, our current research presented the association between six serum aldehydes and sex hormones. Of note, stratification analyses were conducted in participants with different menopausal statuses and age among males and females. Sex- and age-specific effect of aldehyde exposure on alterations in sex hormone levels were observed. Further studies are warranted to confirm the causal relationship and explore the underlying mechanisms.

Synthesis of Ag-Cu co-doping sponge iron-based trimetal for boosting simultaneous degradation of combined pollutants.

To date, zero-valent iron (ZVI)-based technique has encountered a baffle, challenging simultaneous detoxification of refractory rhodamine B (RhB) and p-nitrophenol (PNP) possessing strong electronwithdrawing nitro-group. In this study, we synthesized Ag-Cu decorated sponge iron (s-Fe0)-based trimetal for simultaneous degradation of RhB and PNP. The results show that Cu-Ag co-doping s-Fe0 (s-Fe0-(Cu-Ag)) achieves approx. 90.6 % of maximized removal of RhB; the preferred s-Fe0-(5 wt%Cu-1 wt%Ag) assisted with 6 L/min aeration rate simultaneously declines RhB and PNP within 10 recycling tests; non-aeration process obtains a complete reduction of PNP as well as merely approx. 23.9 % removal of RhB. Moreover, the Cu-Ag microstructure covering s-Fe0-(Cu-Ag) has been characterized in detail. Furthermore, the electron spin resonance (ESR) spectra have been applied to investigate simultaneous generation of reactive oxygen species (ROSs) and hydrogen radicals ([H]abs) over s-Fe0-(Cu-Ag). To our best knowledge, this is the first study reporting the enhanced bifunctional catalysis of s-Fe0-(Cu-Ag)/O2 for simultaneous degradation of RhB and PNP.

Photoinduced Deaminative Alkylation for the Synthesis of γ-Ketoesters via Electron Donor-Acceptor Complex Formation.

Visible-light-induced deaminative alkylation of Katritzky salts with silyl enol ethers has been developed. The reaction can proceed efficiently through electron donor-acceptor complex formation, avoiding the use of precious metal complexes or synthetically elaborate organic dyes. A series of functionalized γ-ketoesters was successfully obtained with good functional group tolerance and compatibility under mild and straightforward conditions.

Transition-metal-free decarboxylative thiolation of stable aliphatic carboxylates.

A transition-metal-free decarboxylative thiolation protocol is reported in which primary, secondary, tertiary (hetero)aryl acetates and α-CN substituted acetates undergo the decarboxylative thiolation smoothly, to deliver a variety of functionalized aryl alkyl sulfides in moderate to excellent yields. Aryl diselenides are also amenable substrates for construction of C-Se bonds under the simple and mild reaction conditions. Moreover, the protocol is successfully applied to the late-stage modification of pharmaceutical carboxylates with satisfactory chemoselectivity and functional-group compatibility.

Engineering the Doping Efficiency in Pentacene Thin Films for High Thermoelectric Performance.

Because of the high mobility and Seebeck coefficient, pentacene (PEN) is a promising candidate for organic small-molecule thermoelectric (TE) materials. However, the low intrinsic conductivity impedes its application in thermoelectricity. In this work, hexacyano-trimethylene-cyclopropane (CN6-CP) is employed as the dopant for PEN via constructing bilayer-structured thin films. The almost intact crystallinity and high charge carrier generation efficiency of these interface-doped PEN films ensure their high conductivity. Time of flight secondary ion mass spectrometry was applied to demonstrate the diffusion of dopant molecules into the PEN layer. UV-vis spectral analysis reveals that integral charge transfer happens between the PEN and CN6-CP molecules. The doping process is further characterized by electron spin-resonance, ultraviolet photoelectron spectroscopy, and X-ray photoelectron spectroscopy analysis. Under optimized conditions, the conductivity of the PEN film deposited on the SiO2/Si substrate can reach up to 10.1 S cm-1. To the best of our knowledge, this is the highest conductivity ever reported for doped PEN thin films. The optimal TE performance with a power factor of 36.4 µW m-1 K-2 can be achieved in the PEN/CN6CP thin film with a Seebeck coefficient and conductivity of 199 µV K-1 and 9.2 S cm-1, respectively. This result shows that interface doping with a strong electron acceptor is a promising approach for optimizing the TE performance of small molecular organic semiconductors.

Band Engineering and Majority Carrier Switching in Isostructural Donor-Acceptor Complexes DPTTA-F X TCNQ Crystals (X = 1, 2, 4).

Three isostructural donor-acceptor complexes DPTTA-F X TCNQ (X = 1, 2, 4) are investigated experimentally and theoretically. By tuning the number of F atoms in the acceptor molecules, the resulting complexes display a continuous down shift of the valence band maximum, conducting band minimum, and optical bandgap. The majority carriers convert from hole (DPTTA-F1TCNQ), balanced hole, and electron (DPTTA-F2TCNQ) to electron (DPTTA-F4TCNQ). This result shows that band engineering can be realized easily in the donor-acceptor complex systems by tuning the electron affinity of the acceptor. The bandgaps of these three complexes vary from 0.31 to 0.41 eV; this narrow bandgap feature is crucial for achieving high thermoelectric performance and the unintentional doping in DPTTA-F4TCNQ leads to the effective suppression of the bipolar cancelling effect on the Seebeck coefficient and the highest power factor.

Synthetic Route to a Triphenylenehexaselenol-Based Metal Organic Framework with Semi-conductive and Glassy Magnetic Properties.

In the latest decade, two-dimensional (2D) π-d conjugated metal organic frameworks (MOFs) constructed from metal ions with square-planar coordination geometry and benzene- or triphenylene-derived ligands with ortho-disubstituted N, O, or S donor atoms have received great research interests because of their exceptional physical properties and promising applications. New MOFs of this class are constantly being reported, but 2D metal bis(diselenolene) MOFs based on organic ligands with ortho-disubstituted Se donor atoms have not been synthesized. Herein, a Lewis-acid-induced dealkylation protocol is introduced to the synthesis of arenepolyselenols and related coordination polymers. A triphenylene-derived diselenaborole compound is synthesized and employed as precursor reagent for the synthesis of 2,3,6,7,10,11-triphenylenehexaselenol (H6TPHS) and the first conductive metal organic framework namely Co-TPHS based on triphenylenehexaselenolate (TPHS6-). Co-TPHS exhibits porous honeycomb 2D structure and electrically conductive and glassy magnetic properties.

Backbone Structure Effect on the Thermoelectric Properties of IDT-Based p-Type Conjugated Polymers.

Four conjugated polymers are synthesized through indacenodithiohene (IDT) unit copolymerized with thiophene and thiophene derivatives. Indacenodithiohene-co-thieno[3,2-b]thiophene (IDT-TT) and indacenodithiohene-co-trans-1,2-di(2-thienyl)ethylene (IDT-TVT) exhibit better charge transport mobilities than indacenodithiohene-co-thiophene (IDT-T) and indacenodithiohene-co-3,4-ethoxylene dioxythiophene (IDT-EDOT), and also display superior thermoelectric properties after doping. Theoretical calculations suggest that IDT-EDOT and IDT-TVT have better coplanarities; the inferior performance for IDT-EDOT might be due to its low molecular weight. Meanwhile, it is worth mentioning that via the synergistic effect of two dopants (CN6CP, CuTFSI), the electrical conductivities of the polymers are further improved. The XPS data shows that the coordination interaction between copper ion and the cyano groups of CN6CP introduces cupric ions into the polymer films, which leads to the increase of the doping ratio.

Visible light-induced palladium-catalyzed ring opening ß-H elimination and addition of cyclobutanone oxime esters.

A palladium catalyst under visible light irradiation activates cyclobutanone oxime ester through single electron transfer to induce radical ring opening to generate hybrid cyanoalkyl Pd(i) radical species. Hybrid cyanoalkyl Pd(i) radical species can undergo either ß-H elimination to deliver (E)-4-arylbut-3-enenitrile or undergo radical addition with silyl enol ether and enamide to generate δ-cyano ketones. A dual ligand system composed of two phosphine ligands is essential for the high reactivity.

Optimization of the thermoelectric performance of layer-by-layer structured copper-phthalocyanine (CuPc) thin films doped with hexacyano-trimethylene-cyclopropane (CN6-CP).

Copper-phthalocyanine (CuPc), as a classical small molecular organic semiconductor, has been applied in many fields. However, the low intrinsic conductivity limits its application in thermoelectricity. Here, hexacyano-trimethylene-cyclopropane (CN6-CP), a strong electron acceptor, is synthesized as dopant for CuPc thin films to improve their conductivities. Multilayer thin films constructed from alternate thermally evaporated CuPc and CN6-CP thin layers are investigated. Under the optimized condition, the doped CuPc film with a conductivity of 0.76 S cm-1 and a Seebeck coefficient of 130 µV K-1, shows a high power factor of 1.3 µW m-1 K-2 and the carrier concentration is estimated to be 2.8 × 1020 cm-3. Considering the relatively superior performance, the CN6-CP doped CuPc film is a promising small molecular organic thermoelectric (OTE) material. In addition, for those highly crystalline materials with poor solubility, the layer-by-layer structure offers a general strategy for investigation and optimization of their TE performance.

Isonicotinate Ester Catalyzed Decarboxylative Borylation of (Hetero)Aryl and Alkenyl Carboxylic Acids through N-Hydroxyphthalimide Esters.

Decarboxylative borylation of aryl and alkenyl carboxylic acids with bis(pinacolato)diboron was achieved through N-hydroxyphthalimide esters using tert-butyl isonicotinate as a catalyst under base-free conditions. A variety of aryl carboxylic acids possessing different functional groups and electronic properties can be smoothly converted to aryl boronate esters, including those that are difficult to decarboxylate under transition-metal catalysis, offering a new method enabling use of carboxylic acid as building blocks in organic synthesis. Mechanistic analysis suggests the reaction proceeds through coupling of a transient aryl radical generated by radical decarboxylation with a pyridine-stabilized persistent boryl radical. Activation of redox active esters may proceed via an intramolecular single-electron-transfer (SET) process through a pyridine-diboron-phthalimide adduct and accounts for the base-free reaction conditions.