Palladium nanoclusters entrapped in polyurea: A recyclable and efficient catalyst for reduction of nitro-benzenes and hydrodechlorination of halogeno-benzenes

Polyurea-entrapped palladium nanoclusters have been prepared by interfacial polymerization in W/O emulsion and showed high thermal stability and chemical stability with the content of 0.12 mmol g^?1 Pd. This catalyst exhibited dual catalytic activity for reduction of nitro compounds and hydrodehalogenation of aromatic chlorides in atmospheric hydrogen with 100% yield for reduction of nitro compounds and >99% yield for hydrodehalogenation of aromatic chlorides. This immobilizing method was particularly effective and eliminated the need of special chelating groups.     

新型吡咯类衍生物的合成

2,5-己二酮和胺(氨基硫脲、硫脲、苯胺、氨基酸)经过Paal-Knorr反应合成6个2,5-二甲基-N-取代吡咯衍生物;分别以新合成的N-吡咯甘氨酸、N-苯基吡咯化合物为原料,进行酯化反应和Mannich,Friedel-Craft反应,合成3个N-(2,5-二甲基吡咯)甘氨酸酯类化合物和2个N-苯基-2,5-二甲基吡咯衍生物.所有化合物都通过IR,1HNMR,13CNMR,HRMS波谱方法对其结构进行了确证.     

Development of metallocomplex amino acids synthons for the asymmetric preparation of α-amino acids by stereoselective introduction of a side chain. Evaluation of the model asymmetric preparation of alanine and β-13C monolabelled α-aminoisobutyric acid

In this communication the evaluation of eleven new metallocomplex alanine synthons bearing C₂-symmetric benzyl groups with electron-donating and electron-withdrawing substituents is described. α-Methylated glycine synthons (alanine complexes) were evaluated alongside alanine synthons in order to obtain a deeper understanding of the relationship between their structures and stereochemistry of monoalkylated products and to choose several candidates for their further tests for stereospecific preparation of 6-[¹⁸F]FDOPA. Glycine-derived analogues of the complexes 3–5 are the best candidates for the development of a 6-[¹⁸F]FDOPA preparation procedure. In the model epimerisation reaction they demonstrated the best performance, much better compared to the previously described compound 2. Complexes 3, 5 and 8 are the best in asymmetric preparation of β-¹³C monolabelled α-aminoisobutyric acid. They have to be tested in the preparation of α-methyl amino acids like 6-[¹⁸F]-α-methylDOPA and 2-[¹⁸F]-α-methyltyrosine.     

FT-IR study of gamma-radiation induced degradation of polyvinyl alcohol (PVA) and PVA/humic acids blends

Samples of pure polyvinyl alcohol (PVA) and PVA doped with humic acids were exposed to gamma radiation. Gamma rays induced the degradation of the pure polymer. Degradation changes were observed using ATR FT-IR equipment. Dehydration, double bond creation, and their subsequent oxidation (surrounding atmosphere was air) were found out. Also, other degradation reactions (e.g. chain scission, cyclization) occur simultaneously. Formation of C=C and C=O bonds is apparent from FT-IR spectra. In contrast the presence of humic acids in the PVA sample showed stabilizing effect on PVA structure within the concentration range 0.5–10%.     

Synthesis and antiviral activities of synthetic glutarimide derivatives

A series of novel glutarimide compounds were synthesized and their antiviral activities were evaluated. The compounds displaying the strongest antiviral activities included 5, 6f, 7e and 9 against coxsackievirus B3 (Cox B3), 10 and 6f against influenza virus A (influenza A) and 7a against herpes simplex virus 2 (HSV-2). However, most of the synthetic glutarimides showed comparatively much weaker activity against influenza A, Cox B3 and HSV-2 than the natural glutarimide compounds tested. Based on the results, it seemed likely that a conjugated system at the β-substituted moiety provides stronger antiviral activity.     

Synthesis and structure of dinuclear dimethylene- or 1,4-phenylene-linked bis(decamethyltitanoceneoxide) (Ti) complexes

The singly tucked-in titanocene [Ti(η⁵-C₅Me₅)(η⁵:η¹-C₅Me₄CH₂)] (1) reacts smoothly with ethylene glycol or hydroquinone to give bis(titanoceneoxide) (Ti^III) complexes [CH₂OTi(η⁵-C₅Me₅)₂]₂ (2) and [(η⁵-C₅Me₅)₂TiOC₆H₄OTi(η⁵-C₅Me₅)₂] (3) containing dimethylene and 1,4-phenylene link, respectively. EPR spectra of 2 in 2-methyltetrahydrofuran glass and 3 in toluene glass revealed that the unpaired d¹ electrons are in interaction to form triplet state molecules. The Ti-Ti distance derived from the zero-field splittings D for the two conformations of 2 (7.42 Å and 7.66 Å) are in good agreement with the Ti-Ti distance of 7.2430(7) Å from the X-ray diffraction single-crystal analysis. For 3, however, the Ti-Ti distance derived from D (7.65 Å) is by 1.47 Å shorter than the crystallographic distance of 9.1230(8) Å that indicates an enhancement of the through-space dipole-dipole interaction due to the presence of a conjugated quinonide link.     

堆焊熔敷层表面纳米晶层摩擦磨损性能研究

用预压力滚压技术在堆焊修复层表面制备纳米晶层.利用TEM、SEM分析技术研究表面纳米晶层微观结构,利用CETR-3型多功能摩擦磨损试验机考察在干摩擦条件下堆焊层表面纳米晶层的摩擦磨损性能.结果表明堆焊修复层表面经表面纳米化处理后,表面形成厚度约为10μm(晶粒尺寸小于100 nm)的纳米晶层,最表面层平均晶粒尺寸约为10 nm.纳米压痕试验表明纳米晶层的硬度提高,最表面纳米晶层的硬度约为原始堆焊层硬度的3倍.与原始堆焊试样相比,表面纳米化试样的摩擦系数降低了10%,磨损体积降低了25%~30%左右.表面纳米化样品的磨损机制由原始堆焊层的磨粒磨损和黏着磨损转变为磨粒磨损,分析表明晶粒细化导致的高硬度、低塑性是摩擦磨损性能改善和磨损机制改变的主要原因.     

Adapting decarbonylation chemistry for the development of prodrugs capable of in vivo delivery of carbon monoxide utilizing sweeteners as carrier molecules

Carbon monoxide as an endogenous signaling molecule exhibits pharmacological efficacy in various animal models of organ injury. To address the difficulty in using CO gas as a therapeutic agent for widespread applications, we are interested in developing CO prodrugs through bioreversible caging of CO in an organic compound. Specifically, we have explored the decarboxylation–decarbonylation chemistry of 1,2-dicarbonyl compounds. Examination and optimization of factors favorable for maximal CO release under physiological conditions led to organic CO prodrugs using non-calorific sweeteners as leaving groups attached to the 1,2-dicarbonyl core. Attaching a leaving group with appropriate properties promotes the desired hydrolysis–decarboxylation–decarbonylation sequence of reactions that leads to CO generation. One such CO prodrug was selected to recapitulate the anti-inflammatory effects of CO against LPS-induced TNF-α production in cell culture studies. Oral administration in mice elevated COHb levels to the safe and efficacious levels established in various preclinical and clinical studies. Furthermore, its pharmacological efficacy was demonstrated in mouse models of acute kidney injury. These studies demonstrate the potential of these prodrugs with benign carriers as orally active CO-based therapeutics. This represents the very first example of orally active organic CO prodrugs with a benign carrier that is an FDA-approved sweetener with demonstrated safety profiles in vivo.

1,2-Dicarbonyl compounds with FDA-approved sweeteners as leaving groups deliver CO for protection against acute kidney injury in mice.     

Application of SPE Using Multi-Walled Carbon Nanotubes as Adsorbent and Rapid Resolution LC-MS-MS for the Simultaneous Determination of 11 Triazine Herbicides Residues in River Water

A method for the simultaneous determination of 11 triazine herbicides residues in river water has been developed. It involves solid-phase extraction (SPE) pretreatment step and rapid resolution liquid chromatography-tandem mass spectrometry (RRLC-MS-MS). In the SPE pretreatment step, the adsorptive performance of MWCNTs material as SPE adsorbent and the elution capability of five kinds of solvents were investigated; in the LC separation step, a rapid resolution high throughput LC column, was used and the gradient elution mode adopted. The linear correlation coefficients (r ²) of the method for 11 target analytes varied between 0.9930 and 0.9980, the mean recoveries were in the range of 73.0 and 98.0% with relative standard deviations (RSD) 2.6 ~ 4.2%, the method detection limits (MDL) were all below 0.1 ng L^?1. An expanded uncertainty of not more than 20% was estimated for each analyte at the spiked concentration of 4.0 μg L^?1. The proposed method was applied to the determination of the residue concentrations of 11 pollutants in Songhuajiang River water.