Decarboxylative Sulfonylation of Carboxylic Acids under Mild Photomediated Iron Catalysis.

Organic sulfones are an important class of chemical compounds widely used in many research fields. The direct decarboxylative sulfonylation of carboxylic acids is attractive but challenging, particularly when iron is used as a metal catalyst. Herein, we describe a photoinduced iron-catalytic method for the synthesis of sulfones directly using carboxylic acids via a radical-based decarboxylation. This protocol is mild, highly efficient, and easy-to-operate. A broad scope of carboxylic acids and carbon electrophiles could be well tolerated. A mechanism involving the iron-catalyzed decarboxylation, radical transfer, single-electron reduction, and nucleophilic attack is proposed.

Iron-Catalyzed Csp2-Csp3 Cross-Coupling via Double Decarboxylation: One Step Synthesis of Remote Polar Alkenes.

Herein, we report an efficient photoinduced iron-catalyzed strategy for cross-couplings of alkyl carboxylic and acrylic acids, which provides a powerful tool for the synthesis of a variety of alkenes with polar functional groups. This novel synthetic methodology can also be applied to the preparation of ketones by using α-keto acids. Mechanistic experiments revealed preliminary mechanistic details. Diverse functionalization could be achieved, which may help streamline the synthesis of complex analogues for drug discovery.

Runx2 heterozygosity alters homeostasis of the periodontal complex.

BACKGROUND AND OBJECTIVE: Haploinsufficiency of Runx2 (Runx2+/- ) causes dental anomalies. However, little is known about the involvement of Runx2 in the maintenance of dentin, cementum, and the periodontal ligament (PDL) during adulthood. This study aimed to observe the effects of Runx2+/- on homeostasis of the periodontal complex. MATERIALS AND METHODS: A total of 14 three-month-old Runx2+/- mice and their wild-type littermates were examined using micro-computed tomography, histology, and immunohistochemistry. Phenotypic alterations in the dentin, cementum, and PDL were characterized and quantified. RESULTS: Haploinsufficiency of Runx2 caused cellular changes in the PDL space including reduction of cell proliferation and apoptosis, and irregular attachment of the collagen fibers in the PDL space into the cementum. Absence of continuous thickness of cementum was also observed in Runx2+/- mice. CONCLUSION: Runx2 is critical for cementum integrity and attachment of periodontal fibers. Because of its importance to cementum homeostasis, Runx2 is essential for homeostasis of periodontal complex.

Long-term Stability Over 2 Years After Isolated Maxillary Orthognathic Surgery Combined With Mandibular Autorotation in Risk Patients for Condylar Resorption.

OBJECTIVE: Counterclockwise rotation of mandible can cause condylar resorption and condylar displacement posteroinferiorly after maxillary orthognathic surgery with mandibular in patients with high-angle mandibular retrognathism. This study was aimed to evaluate long-term stability >2 years and postoperative changes of condylar displacement. MATERIALS AND METHODS: In 15 patients who underwent Le Fort I osteotomy with mandibular autorotation, postoperative stability was cephalometrically investigated until 2 years. Condylar changes were analyzed with transcranial temporomandibular joint projection. Correlation between condylar displacement and surgical movement was analyzed. RESULTS: Significant clockwise relapse of mandible ( P <0.01 for SNB reduction and backward movement of point B) was observed between 6 months and >2 years after surgery, even though the values were small (0.5±0.1 degrees and 1.14±0.13 mm, respectively). The condyle was displaced posteroinferiorly immediately after surgery; however, it achieved a stable position at postoperative 6 weeks. The amount of vertical condylar displacement was significantly correlated with surgical change in mandibular posterior border sagittal angle, palatal plane angle, facial height ratio, and point B in the horizontal dimension. Greater mandibular rotation prompted more vertical condylar displacement. CONCLUSIONS: Small mandibular relapse in long term should be considered after maxillary orthognathic surgery with mandibular autorotation, although it is regarded as a surgical maneuver to minimize mandibular instability in patients susceptible to postoperative condylar resorption.

Huoxue Jiangtang Decoction Alleviates Type 2 Diabetes Mellitus by Regulating the Oral Microbiota and Food Preferences.

Purpose: As a formula of traditional Chinese medicine (TCM), Huoxue Jiangtang Decoction (HJD) has positive effects on diabetes mellitus (DM) through improving of the metabolism of glycolipid and the function of ß-cell. Hence, this research aims to explore the potential therapeutic effects of HJD on diabetes and reveal its underlying mechanisms. Methods: Diabetic rat models induced by high-fat diet (HFD) and streptozotocin (STZ) were included in this study. Following successful modeling, diabetic rats were treated with HJD, and then its therapeutic effects in eight weeks were evaluated. In addition to biochemical indicators, two-bottle preference tests were carried out to examine the rats' preferences for fat and sugar, and 16S rRNA gene sequencing was performed to disclose the differences of oral microbiota among groups. Finally, Pearson correlation coefficient was used to explore the correlation between oral microbiota and the preferences for fat and sugar. Results: It was found that HJD significantly improved the levels of fasting blood glucose (FBG), glucose tolerance, and dyslipidemia. Additionally, HJD contributed to decreasing preferences for fat and sugar in diabetic rats, which plays an important role in food intake. Furthermore, HJD regulated the abundance, distribution, and structure of oral microbiota in diabetic rats, serving as one of the underlying mechanisms of its antidiabetic effects. Conclusion: Taken with other formulas, HJD functions to improve the metabolism of glycolipid and the function of ß-cell by inhibiting preferences for fat and sugar, as well as regulating the oral microbiota of diabetic rats. Furthermore, a potential correlation between the oral micro-environment and preferences for fat and sugar in STZ-induced diabetic rats is likely to exist.

Mild Amide Synthesis Using Nitrobenzene under Neutral Conditions.

Amide synthesis is one of the most important transformations in organic chemistry due to the broad application in pharmaceutical drugs and organic materials. In this report, we describe a mild protocol for amide formation using the readily available nitroarenes as nitrogen sources and an inexpensive iron complex as a catalyst. Because of the use of the pH-neutral conditions and the avoidance of the strong oxidant or reductant, a wide range of aromatic and aliphatic aldehydes as well as nitroarenes with various functional groups could be tolerated well. A plausible mechanism is proposed based on the detailed studies, in which iron catalyst initiates the radical process and the solvent plays a key role as O-atom acceptor.

Iron-Catalyzed Photoinduced Remote C(sp3)-H Amination of Free Alcohols.

We report a general photocatalytic protocol for the remote C(sp3)-H bond amination of free aliphatic alcohols. The electron transfer between the abundant and inexpensive catalyst FeCl3 and simple alkanols under blue LED irradiation enables the alkoxy radical formation under mild redox-neutral conditions, with no need for additional oxidant and prefunctionalization. The subsequent selective 1,5-hydrogen atom transfer (HAT) and amination provide a simple and efficient way to access molecular complexity from readily available and bulk alcohols.

Indium-mediated annulation of 2-azidoaryl aldehydes with propargyl bromides to [1,2,3]triazolo[1,5-a]quinolines.

An efficient indium-mediated cascade annulation reaction of 2-azidoaryl aldehydes with propargyl bromides is reported. The aromatic 5/6/6-fused heterocycles, [1,2,3]triazolo[1,5-a]quinoline derivatives, could be constructed in one pot in moderate yields with a broad substrate scope. Mechanistic studies indicated that the reaction proceeded through allenol formation, azide-allene [3 + 2] cycloaddition, and dehydration. The synthetic potential of the products including the denitrogenative functionalization and the Pd-catalyzed coupling reactions has also been explored.

Oxidative α-C-C Bond Cleavage of 2° and 3° Alcohols to Aromatic Acids with O2 at Room Temperature via Iron Photocatalysis.

The selective α-C-C bond cleavage of unfunctionalized secondary (2°) and tertiary alcohols (3°) is essential for valorization of macromolecules and biopolymers. We developed a blue-light-driven iron catalysis for aerobic oxidation of 2° and 3° alcohols to acids via α-C-C bond cleavages at room temperature. The first example of oxygenation of the simple tertiary alcohols was reported. The iron catalyst and blue light play critical roles to enable the formation of highly reactive O radicals from alcohols and the consequent two α-C-C bond cleavages.

Mobile Robot Path Planning Based on Time Taboo Ant Colony Optimization in Dynamic Environment.

This article aims to improve the problem of slow convergence speed, poor global search ability, and unknown time-varying dynamic obstacles in the path planning of ant colony optimization in dynamic environment. An improved ant colony optimization algorithm using time taboo strategy is proposed, namely, time taboo ant colony optimization (TTACO), which uses adaptive initial pheromone distribution, rollback strategy, and pheromone preferential limited update to improve the algorithm's convergence speed and global search ability. For the poor global search ability of the algorithm and the unknown time-varying problem of dynamic obstacles in a dynamic environment, a time taboo strategy is first proposed, based on which a three-step arbitration method is put forward to improve its weakness in global search. For the unknown time-varying dynamic obstacles, an occupancy grid prediction model is proposed based on the time taboo strategy to solve the problem of dynamic obstacle avoidance. In order to improve the algorithm's calculation speed when avoiding obstacles, an ant colony information inheritance mechanism is established. Finally, the algorithm is used to conduct dynamic simulation experiments in a simulated factory environment and is compared with other similar algorithms. The experimental results show that the TTACO can obtain a better path and accelerate the convergence speed of the algorithm in a static environment and can successfully avoid dynamic obstacles in a dynamic environment.

Carboxylation as an effective approach to improve the adsorption performance of graphene materials for Cu2+ removal.

Graphene materials are high-performance adsorbents for water and soil remediation, whose oxygen containing groups bind to metal ions intensely. In this study, we prepared carboxylated graphene oxide (GO-OCH2COOH) sponge and investigated the adsorption behaviors of Cu2+ on it by both experimental and computational approaches. Carboxylation largely improved the adsorption capacity from 23.8mg/g for graphene oxide (GO) sponge to 93.8mg/g for GO-OCH2COOH. The efficient adsorption was due to the strong interaction between Cu2+ and carboxyl groups (especially in -OCH2COOH form) according to the density functional theory calculation, while epoxy and hydroxyl groups contributed lowly. The fast adsorption process was achieved within 30min, corresponding to a large k2 value of pseudo-second order model (0.061mg/g/min). The adsorption was spontaneous and exothermic according to thermodynamics analyses. The binding strength of Cu2+ on GO-OCH2COOH was so strong that pH and ionic strength had mild impact. The strong binding sites were not recyclable, but the weaker ones (more than 40%) could be regenerated by simple washing. Our results highlighted the importance of chemical design in graphene adsorbents and the potential of GO-OCH2COOH in heavy metal fixation from water and soil.

Selenization of Cu2ZnSnS4 Enhanced the Performance of Dye-Sensitized Solar Cells: Improved Zinc-Site Catalytic Activity for I3.

Cu2ZnSnS4 (CZTS) and Cu2ZnSn(S,Se)4 (CZTSSe) as promising photovoltaic materials have drawn much attention because they are environmentally benign and earth-abundant elements. In this work, the monodispersed, low-cost Cu2ZnSnS4 nanocrystals with small size have been controllably synthesized via a wet chemical routine. And CZTSSe could be easily prepared after selenization of CZTS. When they are employed as counter electrodes (CEs) for dye-sensitized solar cells (DSSCs), the power conversion efficiency (PCE) has been improved from 3.54% to 7.13% as CZTS is converted to CZTSSe, which is also compared to that of Pt (7.62%). The exact reason for the enhanced catalytic activity of I3- is discussed with the work function and density functional theory (DFT) when CZTSSe converted from CZTS. The results of a Kelvin probe suggest that the work function of CZTSSe (5.61 eV) is closer to that of Pt (5.65 eV) and higher than that of CZTS, which matched the redox shuttle potential better. According to the theory calculation, all the atomic and bond populations changed significantly when Se replaced partly the S on the CZTS system, especially in the Zn site. During the catalytic process as CEs, the adsorption energy obviously increased compared to those at other sites when I3- adsorbed on the Zn site in CZTSSe. So, Zn plays an important role for the reduction of I3- after CZTS is converted to CZTSSe. Based on above analysis, the reason for enhanced performance of DSSCs when CZTS converted to CZTSSe is mainly due to the enhancement of Zn-site activity. This work is beneficial for understanding the catalytic reaction mechanism of CZTS(Se) as CEs of DSSCs.

Flower-Like Nickel Phosphide Microballs Assembled by Nanoplates with Exposed High-Energy (0 0 1) Facets: Efficient Electrocatalyst for the Hydrogen Evolution Reaction.

The fabrication of low-cost and earth-abundant electrocatalysts for the hydrogen evolution reaction (HER) over a broad pH range is attractive. In this work, a facile precursor route is developed to synthesize flower-like nickel phosphide microballs with a diameter of approximately 12 µm. With a controlled phosphorization temperature, flower-like nickel phosphide microballs with different crystalline structures (Ni5 P4 and Ni2 P) were obtained easily. Flower-like Ni5 P4 microballs possessed two advantageous features for enhanced HER: fast vectorial electron transfer path along the building block nanoplates and enhanced inherent catalytic activity of each active site for high-energy (0 0 1) facets. The flower-like Ni5 P4 microballs electrocatalyst thus displayed excellent activity for the HER with a low overpotential (η) of 35.4 mV to reach current densities of 10 mA cm-2 and a small Tafel slope of 48 mV dec-1 in acid solution. In addition, it showed excellent activity in 1 m KOH with η=47 mV at 10 mA cm-2 . DFT studies indicated that the free energy of hydrogen adsorbed on the Ni site of Ni5 P4 was 0.152 eV, which is smaller than that of the Ni site of Ni2 P (0.182 eV). Therefore, flower-like Ni5 P4 microballs exhibited better HER activity than Ni2 P, which is consistent with our HER data. This hierarchical structure with exposed high-energy (0 0 1) facets paves the way to design and synthesize low-cost, high-performance catalysts for the HER.