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Phosphaphenalenes, extended π conjugates with the incorporation of phosphorus, are attractive avenues towards molecular materials for the applications in organic electronics, but their electron accepting ability have not been investigated. Herein we present systematic studies on the reductive behavior of a representative phosphaphenalene and its oxide by chemical and electrochemical methods. The chemical reduction of the phosphaphenalene by alkali metals reveals the facile P−C bond cleavage to form phosphaphenalenide anion, which functions as a transfer block for structure modification on the phosphorus atom. In contrast, the pentavalent P‐oxide reacts with one or two equivalents of elemental sodium to form stable radical anion and dianion salts, respectively. [ABSTRACT FROM AUTHOR]

Defects can predominantly dictate the properties of oxide materials, in particular, photocatalytic and electrical properties. By implanting the defects of metallic element, Cu atom doped ZnO (Cu1–ZnO) supported by graphene-coated polyethylene-terephthalate (GPET) transparent substrate has been successfully synthesized via hydrothermal method. Our Cu–ZnO/GPET presents a high enhancement of photocatalytic activity by ultraviolet (UV) light illumination, with the degradation efficiency of methylene blue (MB) as high as 83.6%, which is superior to pure ZnO/GPET photocatalyst. Cu can be observed in the form of single atoms through HAADF-STEM tomography. First-principles theoretical calculations show that the d-states of Cu atoms in Cu1–ZnO/GPET become closer to the Fermi level than those of Zn atoms. Upon UV irradiation, doped Cu metal atoms could capture electrons in the conductive band of Cu1–ZnO/GPET and help to separate photogenerated electrons and holes via monovalent Cu and O atoms. Then, electron-rich Cu atoms could activate O2 to form superoxide radicals while the generated holes as oxygen-centered radicals could react with water to form highly active hydroxyl radicals, thus effectively degrading the MB solution. [ABSTRACT FROM AUTHOR]

Single-atom catalysts (SACs) have been applied in many fields due to their superior catalytic performance. Because of the unique properties of the single-atom-site, using the single atoms as catalysts to synthesize SACs is promising. In this work, we have successfully achieved Co1 SAC using Pt1 atoms as catalysts. More importantly, this synthesis strategy can be extended to achieve Fe and Ni SACs as well. X-ray absorption spectroscopy (XAS) results demonstrate that the achieved Fe, Co, and Ni SACs are in a M1-pyrrolic N4 (M= Fe, Co, and Ni) structure. Density functional theory (DFT) studies show that the Co(Cp)2 dissociation is enhanced by Pt1 atoms, thus leading to the formation of Co1 atoms instead of nanoparticles. These SACs are also evaluated under hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), and the nature of active sites under HER are unveiled by the operando XAS studies. These new findings extend the application fields of SACs to catalytic fabrication methodology, which is promising for the rational design of advanced SACs. Synthesizing single-atom catalysts through a general method presents a great challenge. Here the authors report that Fe, Co and Ni single-atom catalysts can be obtained using pre-located isolated Pt atoms as the catalyst and identify the role of Pt single atoms in the synthesis process. [ABSTRACT FROM AUTHOR]

Due to the enigmatic existence of the carbon atom in the MoFeS cluster of iron‐molybdenum cofactor (FeMoco), the design of biomimetic model catalysts featuring a dative bond between a transition metal and a main group atom is an important topic for efficient reduction of N2 to NH3 at ambient conditions. Different anchor atoms (X) for the trigonal bipyramidal (XPiPr3)Fe (X = B, C, N) catalyst scaffold are investigated by theory. The calculations show that from Lewis acidic B anchor to Lewis basic N or P anchor, the molecular orbital energy levels consisting mainly of Fe 3d orbitals are pushed higher, thus causing stronger backdonation bonding with the π* orbitals of N2, which promotes activation of N2 but impedes reduction of N2. The redox‐flexible bonding can act as an electron reservoir and buffer the oxidation state variation of Fe. However, when the FeX bond is less flexible, the peripheral ligands can serve as an extra electron reservoir in the model with Lewis basic anchor. Thus, engineering the peripheral ligand with proper electron‐withdrawing substituent groups can promote reduction of N2. The ability to balance well the electron‐donating ability of anchor and electrophilicity of the peripheral ligand is a promising direction toward novel efficient catalysts for N2 fixation. [ABSTRACT FROM AUTHOR]

Male diabetic individuals present a marked impairment in fertility; however, knowledge regarding the pathogenic mechanisms and therapeutic strategies is unsatisfactory. The new hypoglycemic drug dapagliflozin has shown certain benefits, such as decreasing the risk of cardiovascular and renal events in patients with diabetes. Even so, until now, the effects and underlying mechanisms of dapagliflozin on diabetic male infertility have awaited clarification. Here, we found that dapagliflozin lowered blood glucose levels, alleviated seminiferous tubule destruction, and increased sperm concentrations and motility in leptin receptor-deficient diabetic db/db mice. Moreover, the glucagon-like peptide-1 receptor (GLP-1R) antagonist exendin (9-39) had no effect on glucose levels but reversed the protective effects of dapagliflozin on testicular structure and sperm quality in db/db mice. We also found that dapagliflozin inhibited the testicular apoptotic process by upregulating the expression of the antiapoptotic protein B-cell lymphoma 2 (BCL2) and X-linked inhibitor of apoptosis protein (XIAP) and inhibiting oxidative stress by enhancing the antioxidant status, including total antioxidant capacity, total superoxide dismutase (SOD) activity, and glutathione peroxidase (GPx) activity, as well as decreasing the level of 4-hydroxynonenal (4-HNE). Exendin (9-39) administration partially reversed these effects. Furthermore, dapagliflozin upregulated the glucagon-like peptide-1 (GLP-1) level in plasma and GLP-1R expression by promoting AKT8 virus oncogene cellular homolog (Akt) phosphorylation in testicular tissue. Exendin (9-39) partially inhibited Akt phosphorylation. These results suggest that dapagliflozin protects against diabetes-induced spermatogenic dysfunction via activation of the GLP-1R/phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway. Our results indicate the potential effects of dapagliflozin against diabetes-induced spermatogenic dysfunction., Competing Interests: None