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71.
72.
Dr. Amineh Aghabali Sharon Jun Prof. Dr. Marilyn M. Olmstead Prof. Dr. Alan L. Balch 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(52):18908-18915
The photochemical reaction of piperazine with C70 produces a mono‐adduct (N(CH2CH2)2NC70) in high yield (67 %) along with three bis‐adducts. These piperazine adducts can combine with various Lewis acids to form crystalline supramolecular aggregates suitable for X‐ray diffraction. The structure of the mono‐adduct was determined from examination of the adduct I2N(CH2CH2)2NI2C70 that was formed by reaction of N(CH2CH2)2NC70 with I2. Crystals of polymeric {Rh2(O2CCF3)4N(CH2CH2)2NC70}n?nC6H6 that formed from reaction of the mono‐adduct with Rh2(O2CCF3)4 contain a sinusoidal strand of alternating molecules of N(CH2CH2)2NC70 and Rh2(O2CCF3)4 connected through Rh?N bonds. Silver nitrate reacts with N(CH2CH2)2NC70 to form black crystals of {(Ag(NO3))4(N(CH2CH2)2NC70)4}n?7nCH2Cl2 that contain parallel, nearly linear chains of alternating (N(CH2CH2)2NC70 molecules and silver ions. Four of these {Ag(NO3)N(CH2CH2)2NC70}n chains adopt a structure that resembles a columnar micelle with the ionic silver nitrate portion in the center and the nearly non‐polar C70 cages encircling that core. Of the three bis‐adducts, one was definitively identified through crystallization in the presence of I2 as 12{N(CH2CH2)2N}2C70 with addends on opposite poles of the C70 cage and a structure with C2v symmetry. In 12{I2N(CH2CH2)2N}2C70, individual 12{I2N(CH2CH2)2N}2C70 units are further connected by secondary I2???N2 interactions to form chains that occur in layers within the crystal. Halogen bond formation between a Lewis base such as a tertiary amine and I2 is suggested as a method to produce ordered crystals with complex supramolecular structures from substances that are otherwise difficult to crystallize. 相似文献
73.
Kota Tanaka Saki Okamura Ken Shibata Naoki Ikenaga Nobuyuki Tanaka Kazumi Hakamada Jun Miyake 《Research on Chemical Intermediates》2016,42(11):7723-7730
Renewable energy is regarded as a clean energy source but has some problems, one of which is intermittency. To reduce this, the time-delay of hydrogen production by photosynthetic bacteria can be effective. In this study, we qualitatively evaluated the time-delay of hydrogen production by photosynthetic bacteria under various irradiation conditions, and we also quantitatively evaluated it by fitting the experimental data and the hydrogen production model with a genetic algorithm. As a result of model fitting, we found that the relationship between the lengths of the optimized time-delay of hydrogen production by photosynthetic bacteria and the amount of light irradiation is linear. And we also found that the time-delay of hydrogen production by photosynthetic bacteria had an upper limit under low light intensity. We have suggested the existence of an energy store mechanism in photosynthetic bacteria. 相似文献
74.
Dr. Binjie Guo Dr. Xin Huang Prof. Dr. Chunling Fu Prof. Dr. Shengming Ma 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(51):18343-18348
A mild and efficient method using readily available 1‐aryl‐2,3‐allenols and unprotected‐N indoles, Au+‐catalyzed cyclization, and aromatization to afford the final [4C+2C] products, carbazoles 4, with an excellent selectivity, is reported. The reaction demonstrates excellent regioselectivity and allows the N?H unit to undergo reactivity unprotected. A mechanism involving a spiropolycyclic intermediate has been proposed and synthetic application is also demonstrated. 相似文献
75.
Discovery,Characterization, and Analogue Synthesis of Bohemamine Dimers Generated by Non‐enzymatic Biosynthesis 下载免费PDF全文
Dr. Peng Fu Aaron Legako Scott La Prof. Dr. John B. MacMillan 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(10):3491-3495
Dibohemamines A–C ( 5 – 7 ), three new dimeric bohemamine analogues dimerized through a methylene group, were isolated from a marine‐derived Streptomyces spinoverrucosus. The structures determined by spectroscopic analysis were confirmed through the semi‐synthetic derivatization of monomeric bohemamines and formaldehyde. These reactions, which could occur under mild conditions, together with the detection of formaldehyde in the culture, revealed that this dimerization is a non‐enzymatic process. In addition to the unique dimerization of the dibohemamines, dibohemamines B and C were found to have nm cytotoxicity against the non‐small cell‐lung cancer cell line A549. In view of the potent cytotoxicity of compounds 6 and 7 , a small library of bohemamine analogues was generated for biological evaluation by utilizing a series of aryl and alkyl aldehydes. 相似文献
76.
Selective extraction of catecholamines by packed fiber solid‐phase using composite nanofibers composing of polymeric crown ether with polystyrene 下载免费PDF全文
Li‐Qin Chen Yu Wang Jian‐Song Qu Jian‐Jun Deng Xue‐Jun Kang 《Biomedical chromatography : BMC》2015,29(1):103-109
For the first time, electrospun composite nanofibers comprising polymeric crown ether with polystyrene (PCE‐PS) have been used for the selective extraction of catecholamines – dopamine (DA), norepinephrine (NE) and epinephrine (E) – prior to their analysis by high‐performance liquid chromatography–electrochemical detection. Using a minicartridge packed with PCE‐PS composite nanofibers, the target compounds were extracted effectively from urine samples to which diphenylborinic acid 2‐aminoethyl ester was added as a complexing reagent. The extracted catecholamines could be liberated from the fiber by the addition of acetic acid. A good linearity was observed for catecholamines in the range of 2.0–200 ng mL?1 (NE, E and DA). The detection limits of catecholamines (signal‐to‐noise ratio = 3) were 0.5 ng mL?1 (NE), 0.2 ng mL?1 (E) and 0.2 ng mL?1 (DA), respectively. Under the optimized conditions, the absolute recoveries of the above three catecholamines were 90.6% (NE), 88.5% (E) and 94.5% (DA). The repeatability of extraction performance was from 5.4 to 9.2% (expressed as relative standard deviation). Our results indicate that the proposed method could be used for the determination of NE, E and DA in urine. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
77.
Development of an LC‐MS/MS method for determining the pharmacokinetics of clonidine following oral administration of Zhenju antihypertensive compound 下载免费PDF全文
Jing Qin Limin Wang Lihong Wu Jun Chen Teng Shen Yongji Li Limei Han Jianxin Wang 《Biomedical chromatography : BMC》2015,29(7):1068-1075
Zhenju antihypertensive compound (ZJAHC) is a combined Chinese–Western medicine formula including clonidine (CLO), hydrochlorothiazide (HCT), rutin, Chrysanthemum indicum extract and pearl powder. Compared with CLO preparations, ZJAHC shows improved activities and decreased adverse effects. It is believed that the side effects of CLO are caused by its high peak plasma concentration. Hence, study of the influence of ZJAHC on the pharmacokinetic behaviors of clonidine seems essential. In present study, the plasma concentrations of CLO were determined with a liquid chromatography–tandem mass spectrometry (LC‐MS/MS) method. The MS/MS transitions monitored for clonidine and internal standard were 230.2 → 213.1 and 152.2 → 110.2, respectively. The analyte was quantified in a single run within 3 min. The pharmacokinetic study showed that the area under the plasma concentration–time curve of CLO in ZJAHC (60 µg/kg CLO) was similar to that of CLO‐HCT‐high (120 µg/kg CLO) but the peak concentration was much lower than that in CLO‐HCT‐high. ZJAHC could enhance the bioavailability without greatly increasing peak concentration of clonidine. This comprehensive effect of enhancing the bioavailability and avoiding the high peak plasma concentration for CLO might mainly result from the co‐contribution of Western medicine and traditional Chinese medicine (TCM), while the effect of TCM was stronger than that of Western medicine. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
78.
In this paper, we prove that any nonlinear Jordan higher derivation on triangular algebras is an additive higher derivation. As a byproduct, we obtain that any nonlinear Jordan derivation on nest algeb... 相似文献
79.
TBAI‐Catalyzed/Water‐Assisted Double C−S Bond Formations: An Efficient Approach to Sulfides through Metal‐Free Three‐Component Reactions 下载免费PDF全文
Xue‐Qiang Chu Prof. Dr. Xiao‐Ping Xu Prof. Dr. Shun‐Jun Ji 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(40):14181-14185
An aqueous catalytic method for double C?S bond formations that involves alcohol derivatives, organic halides, and sodium thiosulfate has been developed. A diverse range of functionalized sulfides, including pharmaceutical and biological derivatives, can be obtained in an efficient and eco‐friendly manner under air. The mechanistic studies revealed that this tetrabutylammonium‐iodide‐catalyzed/water‐assisted reaction generated a mercaptan species as the key intermediate. 相似文献
80.
Enhanced Catalytic Activity in Liquid‐Exfoliated FeOCl Nanosheets as a Fenton‐Like Catalyst 下载免费PDF全文
Jian Zhang Prof. Xiu‐Ling Jiao Dr. Yu‐Guo Xia Fang‐Fang Liu Ying‐Ping Pang Xin‐Fu Zhao Prof. Dai‐Rong Chen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(27):9321-9329
A facile liquid‐phase exfoliation method to prepare few‐layer FeOCl nanosheets in acetonitrile by ultrasonication is reported. The detailed exfoliation mechanism and generated products were investigated by combining first‐principle calculations and experimental approaches. The similar cleavage energies of FeOCl (340 mJ m?2) and graphite (320 mJ m?2) confirm the experimental exfoliation feasibility. As a Fenton reagent, FeOCl nanosheets showed outstanding properties in the catalytic degradation of phenol in water at room temperature, under neutral pH conditions, and with sunlight irradiation. Apart from the increased surface area of the nanosheets, the surface state change of the nanosheets also plays a key role in improving the catalytic performance. The changes of charge density, density of states (DOS), and valence state of Fe atoms in the exfoliated FeOCl nanosheets versus plates illustrated that surface atomistic relationships made the few‐layer nanosheets higher activity, indicating the exfoliation process of the FeOCl nanosheets also brought about surface state changes. 相似文献