A novel fluorescent probe for formaldehyde based-on monomer-excimer conversion and its imaging in live cells

A novel fluorescent probe was developed for formaldehyde, which can be synthesized by one-step Buchwald–Hartwig reaction. When hydrazino-group of probe reacted with formaldehyde, hydrophobic reaction product aggregates into nanoparticles and results in the blue fluorescence due to the monomer-excimer effect. With enough sensitivity, high selectivity, good stability in physiological pH range and excellent biocompatibility, this probe can image formaldehyde in living cells.     

Isolation of a new indoxyl alkaloid,Amoenamide B,from Aspergillus amoenus NRRL 35600: Biosynthetic implications and correction of the structure of Speramide B

A new prenylated indoxyl alkaloid, Amoenamide B (1), was isolated from Aspergillus amoenus NRRL 35600 along with Asperochramide A (2). Although many prenylated oxindole alkaloids, containing bicyclo[2.2.2]diazaoctane cores, have been isolated from the fungus of the genera Aspergillus and Penicillium to date, 1 is the fourth compound with the indoxyl unit containing the cores. During the structure elucidation of 1, we found that the planar structure matched to that of Speramide A (3), isolated from A. ochraceus KM007, but the reported structure of 3 was incorrect and turned out to be that of Taichunamide H (4), recently isolated from A. versicolor HDN11-84.     

Syntheses,crystal structures,and properties of two dinuclear iron(III) complexes constructed with 1,2,3,5-benzenetetracarboxylic acid and chelating N-donor auxiliary coligands

Two dinuclear Fe(III) metal–organic complexes with tetracarboxylate and chelating N-donor ligands, [Fe(Hbtec)(phen)(H₂O)]₂·2H₂O (1) and [Fe(Hbtec)(bpy)(H₂O)]₂·2H₂O (2) (H₄btec = 1,2,3,5-benzenetetracarboxylic acid, phen = 1,10-phenanthroline, bpy = 2,2′-bipyridine) have been prepared and characterized by elemental analysis, IR spectroscopic, and X-ray diffraction methods. Both complexes crystallize in the monoclinic space group P2₁/c with two Fe(III) ions bridged by two Hbtec^3? ligands into a dinuclear unit. Hydrogen bonding connects the dinuclear units into a 3-D framework. The dinuclear units are 10-connected nodes that produce a 3-D framework with topology Schläfli symbol as (3¹²·4²⁸·5⁵). Thermal stabilities and luminescent properties of the two complexes have also been investigated.     

蜂窝状Ho改性Fe-Mn/TiO2催化剂的制备及其低温选择催化还原(SCR)脱硝性能

采用模压法制备了蜂窝状Ho改性的Fe-Mn/TiO₂催化剂,研究了结构助剂、黏合剂和造孔剂等对成型催化剂低温选择催化还原（SCR）脱硝性能的影响。优选出一套理想的成型参数：水粉质量比为40%且逐次分批加入;结构助剂玻璃纤维的用量为10%（质量分数）;黏合剂羧甲基纤维素的用量为5%（质量分数）;助挤剂甘油的添加量为10%（质量分数）且分批加入;造孔剂活性炭粉的用量为2%（质量分数）。该蜂窝状催化剂在120 ℃下脱硝率维持在90%以上,并且在SO₂体积分数低于0.02%时具有一定的抗硫抗水性。表征结果表明,成型后蜂窝状催化剂比表面积降低,颗粒分散程度明显减弱,并且表面酸量和表面Mn⁴⁺含量下降,对催化活性有一定的影响。     

Redox Chemistry of Molybdenum Trioxide for Ultrafast Hydrogen‐Ion Storage

Hydrogen ions are ideal charge carriers for rechargeable batteries due to their small ionic radius and wide availability. However, little attention has been paid to hydrogen‐ion storage devices because they generally deliver relatively low Coulombic efficiency as a result of the hydrogen evolution reaction that occurs in an aqueous electrolyte. Herein, we successfully demonstrate that hydrogen ions can be electrochemically stored in an inorganic molybdenum trioxide (MoO₃) electrode with high Coulombic efficiency and stability. The as‐obtained electrode exhibits ultrafast hydrogen‐ion storage properties with a specific capacity of 88 mA hg^?1 at an ultrahigh rate of 100 C. The redox reaction mechanism of the MoO₃ electrode in the hydrogen‐ion cell was investigated in detail. The results reveal a conversion reaction of the MoO₃ electrode into H_0.88MoO₃ during the first hydrogen‐ion insertion process and reversible intercalation/deintercalation of hydrogen ions between H_0.88MoO₃ and H_0.12MoO₃ during the following cycles. This study reveals new opportunities for the development of high‐power energy storage devices with lightweight elements.     

Highly Enantioselective Tandem Michael Addition of Tryptamine‐Derived Oxindoles to Alkynones: Concise Synthesis of Strychnos Alkaloids

A highly enantioselective tandem Michael addition of tryptamine‐derived oxindoles to alkynones was developed by taking advantage of a chiral N,N′‐dioxide Sc(OTf)₃ catalyst. The reaction enables the facile preparation of enantioenriched spiro[pyrrolidine‐3,3′‐oxindole] compounds, which provides a novel strategy for the synthesis of monoterpenoid indole alkaloids. As a demonstration, the asymmetric synthesis of strychnos alkaloids [(?)‐tubifoline, (?)‐tubifolidine, (?)‐dehydrotubifoline] was achieved in 10–11 steps.     

Facile,Quick, and Gram‐Scale Synthesis of Ultralong‐Lifetime Room‐Temperature‐Phosphorescent Carbon Dots by Microwave Irradiation

Long‐lifetime room‐temperature phosphorescence (RTP) materials are important for many applications, but they are highly challenging materials owing to the spin‐forbidden nature of triplet exciton transitions. Herein, a facile, quick and gram‐scale method for the preparation of ultralong RTP (URTP) carbon dots (CDs) was developed via microwave‐assisted heating of ethanolamine and phosphoric acid aqueous solution. The CDs exhibit the longest RTP lifetime, 1.46 s (more than 10 s to naked eye) for CDs‐based materials to date. The doping of N and P elements is critical for the URTP which is considered to be favored by a n→π* transition facilitating intersystem crossing (ISC) for effectively populating triplet excitons. In addition, possibilities of formation of hydrogen bonds in the interior of the CDs may also play a significant role in producing RTP. Potential applications of the URTP CDs in the fields of anti‐counterfeiting and information protection are proposed and demonstrated.     

MaxSynBio: Avenues Towards Creating Cells from the Bottom Up

A large German research consortium mainly within the Max Planck Society (“MaxSynBio”) was formed to investigate living systems from a fundamental perspective. The research program of MaxSynBio relies solely on the bottom‐up approach to synthetic biology. MaxSynBio focuses on the detailed analysis and understanding of essential processes of life through modular reconstitution in minimal synthetic systems. The ultimate goal is to construct a basic living unit entirely from non‐living components. The fundamental insights gained from the activities in MaxSynBio could eventually be utilized for establishing a new generation of biotechnological processes, which would be based on synthetic cell constructs that replace the natural cells currently used in conventional biotechnology.     

Key steps and intermediates in the catalytic mechanism for the reduction of peroxides by the antioxidant ebselen

Hydrogen peroxide and lipid hydroperoxides are formed during aerobic metabolism and contribute to oxidative stress, a major factor in many diseases and degenerative conditions. Although the selenoenzyme glutathione peroxidase (GPx) affords antioxidant protection in vivo by catalytically reducing harmful peroxides with glutathione, certain conditions benefit from the administration of small-molecule GPx mimetics for additional protection. To date, ebselen has been the most widely studied such compound, but its catalytic mechanism is complex and highly variable with conditions. Progress in elucidating the mechanistic details of its antioxidant activity is described in this review.