Biomimetic Donor–Acceptor Motifs in Conjugated Polymers for Promoting Exciton Splitting and Charge Separation

Natural photosynthesis serves as a model for energy and chemical conversions, and motivates the search of artificial systems that mimic nature′s energy‐ and electron‐transfer chains. However, bioinspired systems often suffer from the partial or even large loss of the charge separation state, and show moderate activity owing to the fundamentally different features of the multiple compounds. Herein, a selenium and cyanamide‐functionalized heptazine‐based melon (DA‐HM) is designed as a unique bioinspired donor–acceptor (D‐A) light harvester. The combination of the photosystem and electron shuttle in a single species, with both n‐ and p‐type conductivities, and extended spectral absorption, endows DA‐HM with a high efficiency in the transfer and separation of photoexcited charge carriers, resulting in photochemical activity. This work presents a unique conjugated polymeric system that shows great potential for solar‐to‐chemical conversion by artificial photosynthesis.     

Iridium‐Catalyzed Reductive Alkylations of Secondary Amides

Reported herein is the first direct, metal‐catalyzed reductive functionalization of secondary amides to give functionalized amines and heterocycles. The method is shown to have exceptionally broad scope with respect to suitable nucleophiles, which cover both hard and soft C nucleophiles as well as a P nucleophile. The reaction exhibits good chemoselectivity and tolerates several sensitive functional groups.     

Amino‐Assisted Anchoring of CsPbBr3 Perovskite Quantum Dots on Porous g‐C3N4 for Enhanced Photocatalytic CO2 Reduction

Halide perovskite quantum dots (QDs) have great potential in photocatalytic applications if their low charge transportation efficiency and chemical instability can be overcome. To circumvent these obstacles, we anchored CsPbBr₃ QDs (CPB) on NH_x‐rich porous g‐C₃N₄ nanosheets (PCN) to construct the composite photocatalysts via N?Br chemical bonding. The 20 CPB‐PCN (20 wt % of QDs) photocatalyst exhibits good stability and an outstanding yield of 149 μmol h^?1 g^?1 in acetonitrile/water for photocatalytic reduction of CO₂ to CO under visible light irradiation, which is around 15 times higher than that of CsPbBr₃ QDs. This study opens up new possibilities of using halide perovskite QDs for photocatalytic application.     

A Ligand System for the Flexible Functionalization of Quantum Dots via Click Chemistry

We present a novel ligand, 5‐norbornene‐2‐nonanoic acid, which can be directly added during established quantum dot (QD) syntheses in organic solvents to generate “clickable” QDs at a few hundred nmol scale. This ligand has a carboxyl group at one terminus to bind to the surface of QDs and a norbornene group at the opposite end that enables straightforward phase transfer of QDs into aqueous solutions via efficient norbornene/tetrazine click chemistry. Our ligand system removes the traditional ligand‐exchange step and can produce water‐soluble QDs with a high quantum yield and a small hydrodynamic diameter of approximately 12 nm at an order of magnitude higher scale than previous methods. We demonstrate the effectiveness of our approach by incubating azido‐functionalized CdSe/CdS QDs with 4T1 cancer cells that are metabolically labeled with a dibenzocyclooctyne‐bearing unnatural sugar. The QDs exhibit high targeting efficiency and minimal nonspecific binding.     

生物质炭的制备、改性以及在挥发性有机物吸附方面的应用

挥发性有机物（VOCs）是大气中重要的污染源之一,对环境和人类健康产生严重的危害。吸附法是工业中最常用的去除VOCs的方法,吸附剂是吸附技术的关键,生物质炭是一种由生物质基材料在高温下热解活化等工艺制得的炭材料,具有较高的比表面积、丰富的孔隙结构和化学活性表面,在环境污染控制领域具有广泛应用。基于最近的研究,本文系统地综述了常用于去除VOCs的生物质炭的制备和改性方法,以及生物质炭在吸附VOCs的应用研究。本文首要目标是评估生物质炭去除VOCs的能力,特别是经过各种改性和活化工艺后,评价生物质炭作为吸附剂去除VOCs的适用性;确定改性和活化后对VOCs吸附能力的影响;揭示生物质炭对VOCs可能存在的吸附机理。最后,文章也对生物质炭的再生提出了建议和展望。     

On a kinematic compatibility equation related to elastic stress-free joints and crystal twins

Consider the kinematic compatibility equation QFR = F(I + a n).Here Q and R are two 3×3 matrices representing two rotations, F is a 3×3 matrix with det (F) > 0, I is the 3×3 identity matrix, a and n are two vectors in the 3-dimensional Euclidean space R ³, and a n is the direct product. Assume F and R are given, and we solve for Q, a, n. We will first present a new proof of a criterion, due to Professor Jerry Ericksen, to be met by F and R for the existence of non-trivial solutions. Then we will give sufficient and necessary conditions for F and R under which the equation has solutions of special properties that are related to compound twins and multiple twins in crystals.     

高效毛细管电泳碳柱电极安培电化学检测的理论研究

推导了高效毛细管电泳碳柱电极安培电化学检测的检测电流表达式，并以自制毛细管电泳／电化学检测系统对其进行了实验验证。对给定直径的工作电极，检测电流正比于碳柱工作电极插入检测毛细管长度的２／３次方，也正比于液体电渗平均体积流速的１／３次方。实验结果与公式吻合很好，说明了检测电流表达式的正确性。     

Synthesis and characterization of the novel monoamide derivatives of Gd-TTDA

For this study, the N'-monoamide derivatives of TTDA (3,6,10-tri(carboxymethyl)-3,6,10-triazadodecanedioic acid), N'-methylamide (TTDA-MA), N'-benzylamide (TTDA-BA), and N'-2-methoxybenzylamide (TTDA-MOBA), were synthesized. Their protonation constants and stability constants (log K(ML)'s) formed with Ca(2+), Zn(2+), Cu(2+), and Gd(3+) were determined by potentiometric titration in 0.10 M Me(4)NCl at 25.0 +/- 0.1 degrees C. The relaxivity values of [Gd(TTDA-MA)](-), [Gd(TTDA-BA)](-), and [Gd(TTDA-MOBA)](-) remained constant with respect to pH changes over the range 4.5-12.0. The (17)O NMR chemical shift of H(2)O induced by [Dy(TTDA-MA)(H(2)O)](-) at pH 6.80 showed 0.9 inner-sphere water molecules. Water proton relaxivity values for [Gd(TTDA-MA)(H(2)O)](-), [Gd(TTDA-BA)(H(2)O)](-), and [Gd(TTDA-MOBA)(H(2)O)](-) at 37.0 +/- 0.1 degrees C and 20 MHz are 3.89, 4.21, and 4.25, respectively. The water-exchange lifetime (tau(M)) and rotational correlation time (tau(R)) of [Gd(TTDA-MA)(H(2)O)](-), [Gd(TTDA-BA)(H(2)O)](-), and [Gd(TTDA-MOBA)(H(2)O)](-) are obtained from reduced the (17)O relaxation rate and chemical shifts of H(2)(17)O. The (2)H NMR longitudinal relaxation rates of the deuterated diamagnetic lanthanum complexes for the rotational correlation time were also thoroughly investigated. The water-exchange rates (K(298)(ex) for [Gd(TTDA-MA)(H(2)O)](-), [Gd(TTDA-BA)(H(2)O)](-), and [Gd(TTDA-MOBA)(H(2)O)](-) are lower than that of [Gd(TTDA)(H(2)O)](2)(-) but significantly higher than those of [Gd(DTPA)(H(2)O)](2)(-) and [Gd(DTPA-BMA)(H(2)O)]. The rotational correlation times for [Gd(TTDA-BA)(H(2)O)](-) and [Gd(TTDA-MOBA)(H(2)O)](-) are significantly longer than those of [Gd(TTDA)(H(2)O)](2)(-) and [Gd(DTPA)(H(2)O)](2)(-) complexes. The marked increase of the relaxivity of [Gd(TTDA-BA)(H(2)O)](-) and [Gd(TTDA-MOBA)(H(2)O)](-) results mainly from their longer rotational correlation time. The noncovalent interaction between human serum albumin (HSA) and [Gd(TTDA-BA)(H(2)O)](-) and [Gd(TTDA-MOBA)(H(2)O)](-) complexes containing a hydrophobic substituent was investigated by measuring the water proton relaxation rate of the aqueous solutions. The binding association constant (K(A)) values are 1.0 +/- 0.2 x 10(3) and 1.3 +/- 0.2 x 10(3) M(-1) for [Gd(TTDA-BA)(H(2)O)](-) and [Gd(TTDA-MOBA)(H(2)O)](-), which indicates a stronger interaction of [Gd(TTDA-BA)(H(2)O)](-) and [Gd(TTDA-MOBA)(H(2)O)](-) with HSA.     

无气味、实用的缩硫醛/酮化反应试剂：2-（1，3-二噻-2-亚基）-3-羰基丁酸甲酯

a-Oxo ketene dithioacetals, methyl 2-（1,3-dithian/dithiolan-2-ylidene）-3-oxobutanoate （2a/2b） prepared in nearly quantitative yields simply from methyl acetylacetate, carbon disulfide and 1,3-dibromopropane/1,2-dibromoethane in the presence of potassium carbonate, were investigated in the thioacetalization with various carbonyl compounds 3. It has been demonstrated that methyl 2-（1,3-dithian-2-ylidene）-3-oxobutanoate （2a） could act as a nonthiolic, odorless and practical thioacetalization reagent. A range of aldehydes and ketones 3 were converted into the corresponding dithioacetals 4 in high yields （up to 91%） in the presence of 2a. Moreover, 2a showed high chemoselectivity between aldehyde and ketone in thioacetalization.     

Synthesis and characterization of nitrosyl diruthenium complexes. Interaction between NO and CO across the metal-metal bond

Two neutral diruthenium complexes and one anionic diruthenium complex, Ru2(dpf)4(NO), Ru2(dpf)4(NO)2, and [Ru2(dpf)4(NO)]-, where dpf is diphenylformamidinate anion, were synthesized and characterized as to their electrochemical and spectroscopic properties. Two of the compounds, Ru2(dpf)4(NO) and Ru2(dpf)4(NO)2, were also structurally characterized. Ru2(dpf)4(NO) undergoes reversible one-electron reductions under N2 at E1/2=0.06 and -1.24 V in CH2Cl2, 0.1 M TBABr. These processes are shifted to E1/2=0.18 and -0.78 V under CO due to the trans-coordination of a CO molecule which stabilizes the singly and doubly reduced forms of the metal-metal bonded complexes, thus leading to easier reductions. CO does not coordinate to Ru2(dpf)4(NO), but it does bind to the singly reduced species to generate [Ru2(dpf)4(NO)(CO)]- under a CO atmosphere in solution; characteristic NO and CO bands are seen for this compound at nuNO=1674 cm(-1) and nuCO=1954 cm(-1). Ru2(dpf)4(NO)2 displays a reversible one-electron reduction at E1/2=-1.24 V versus SCE and an irreversible reduction at Epc=-1.96 V in CH2Cl2, 0.1 M TBAP under N2. There are also two reversible one-electron oxidations at E1/2=0.24 and 1.15 V. Spectroelectrochemical monitoring of the Ru2(dpf)4(NO)2 oxidation processes in a thin-layer cell shows only a single NO vibration for each electrogenerated product and nuNO is located at 1726 (neutral), 1788 (singly oxidized), or 1834 (doubly oxidized) cm(-1). Finally, a labile CO complex, [Ru2(dpf)4(NO)(CO)]-, could be generated by passing CO into a solution of [Ru2(dpf)4(NO)]-. Formation of the mixed CO/NO adduct was confirmed by electrochemistry and infrared spectroscopy. Analysis of the NO and CO stretching vibration frequencies for [Ru2(dpf)4(NO)(CO)]- by in-situ FTIR spectroelectrochemistry and comparisons with data for Ru2(dpf)4(NO) and Ru2(dpf)4(CO) reveal the presence of a strong interaction between NO and CO across the Ru-Ru bond.