Unusually sharp dependence of water exchange rate versus lanthanide ionic radii for a series of tetraamide complexes

The tetraamide ligand, DOTA-tetra(glycine ethyl ester), forms complexes with the lanthanide(III) cations that exist in solution predominantly as the square antiprism structure with single, slowly exchanging inner-sphere water molecule. Variable-temperature 1H and 17O NMR studies revealed that the bound water lifetimes in these complexes were sharply dependent upon the ionic radius of Ln3+ cation. A novel lanthanide-induced shift technique was used to unmask the bound water 17O resonance of SmL3+ and YL3+ complexes from the bulk water resonance. The bound water lifetime (tauM298) was approximately 800 mus in the EuL3+ complex but became much shorter (several microseconds) for Ln3+ cations with larger and smaller ionic radii. This demonstrates that water exchange is exquisitely fine-tuned in this macrocyclic tetraamide system and that a variety of Ln3+ complexes meet with the exchange requirement, Deltaomega*tauM >/= 1, necessary for an efficient MT agent.     

极性非质子溶剂与甲醇或1,2-二氯乙烷的汽液平衡

使用双沸点仪测定了丙酮、乙酸乙酯、对二氧六环、乙腈或三乙胺与甲醇或1,2→二氯乙烷以及二者混合物等十一组二元体系在99.3 kPa下的汽液平衡数据(T,x,p), 计算了有关体系的过量吉布斯自由能。结果表明, 六种非质子溶剂与甲醇组成的二元系GE>0; 乙腈或三乙胺与1,2-二氯乙烷组成的二元系GE>0, 而丙酮、乙酸乙酯或对二氧六环与1,2-二氯乙烷的二元混合物GE<0。从同种分子间或不同种分子间的缔合作用对上述结果进行了讨论。本文还在固定极性非质子溶剂(第三组分)物质的量浓度的条件下, 测定了非质子溶剂+1,2-二氯乙烷+甲醇三元混合物的汽液平衡数据, 考察了非质子溶剂的加入对甲醇+1,2-二氯乙烷二元系GE的影响。     

Preparation of Y2Ba4Cu7O15-δ Superconductor without High Oxygen Pressure

The synthesis of bulk Y₂Ba₄Cu₇O_15-δ superconductor at atmospheric oxygen pressure via solid state sintering is reported. Temperature ranging from 860 to 890 °C as well as time interval over 2 to 15 days were used to investigate the formation of the Y₂Ba₄Cu₇O_15-δ phase. A time-temperature profile characterizing the conditions for the preparation of Y₂Ba₄Cu₇O_15-δ phase suggests the optimal condition to be sintering at 890 °C for over 10 days. Detailed results of X-ray diffraction, electrical resistivity, iodometric titration and magnetization measurements are described.     

抗肿瘤药物仑伐替尼合成研究进展

综述了仑伐替尼及其相关主要中间体的合成方法。首先对仑伐替尼逆合成分析,并着重讨论了喹啉环(原料1)以及终产物仑伐替尼的合成。原料1有四种合成方法,对这四种合成方法进行了详细对比与分析,指出第二种合成方法为最佳合成方法。总结了仑伐替尼最常用的两条合成路线并分析优缺点,第一条路线是汇聚式路线,反应时间短、能耗少、成本低、收率高,相比第二条路线更加适合工业化生产。     

微波干法催化芳香醛与绕丹宁及N-苯基绕丹宁的缩合反应

利用微波辐射和固体碱性载体试剂催化绕丹宁及N-苯基绕丹宁和芳香醛的缩合反应合成了14个绕丹宁衍生物并研究了影响反应的因素。     

1,3,2—氧氮磷杂环戊烷衍生物晶体结构研究

用X射线衍射方法测定了两个1,3,2-氧氮磷杂环戊烷衍生物的晶体结构:2-二乙氨基-3-(4′-甲基苯甲酰基)-2-硫代-1,3,2-氧氮磷杂环戊烷,C_(14)H_(21)N_2O_2PS(1),空间群为P_(bco),α=0.9057(5)nm,b=1.3974(6)nm,c=2.5130(7)nm,Z=8,R=0.051;2-二乙氨基-3-(2′,4′-二氯苯甲酰基)-2-硫代-1,3,2-氧氮磷杂环戊烷,C_(13)H_(17)N_2O_2PSCl_2(2),空间群P2_1/c,α=0.7375(1)nm,b=1.4370(3)nm,c=1.6015(7)nm,β=93.70(2)°,Z=4,R=0.054。结构均由直接法解出。两个化合物中氧氮磷杂五元环均为半椅式构象。其中P—N键长环内分别为0.1712(2)nm和0.1723(0)nn;环外为0.1620(3)nm和0.1620(0)nm,由于成环作用所致环内P—N键长大于环外的。     

Repeatability and pattern recognition of bacterial fatty acid profiles generated by direct mass spectrometric analysis of in situ thermal hydrolysis/methylation of whole cells

Direct CI mass spectrometry profiling of fatty acid methyl esters (FAMEs) from in situ thermal hydrolysis/methylation (THM) of whole bacterial cells with tetramethylammonium hydroxide (TMAH) has been demonstrated as a potential method for real time and fieldable detection/identification of microorganisms. Bacillus anthracis (Ames), Yersinia pestis (Nair. Kenya), Vibrio cholerae (E1 Tor), Brucella melitensis (Abortus wild) and Francisella tularensis (LVS vaccine) were profiled by this method during a 10-month period. Repeatability of the in situ FAME data was calculated using one-way analysis of variance (ANOVA) and a t-test. Artificial neural network (ANN) and multivariate statistics of the FAME profiles were also compared for bacterial identification/classification. Equivalent results were obtained with a multivariate rule building expert system (MuRES) and the ANN. However, the ANN analysis required much less computer time and was deemed the best choice for this application. In situ THM FAME profiles of the bacterial samples provided comparable results with those obtained from the Microbial Identification System (MIDI) (Newark, DE) wet chemistry-gas chromatographic based system.     

A direct quantitative analysis method for monitoring biogenic volatile organic compounds released from leaves of Pelargonium hortorum in situ

A direct quantitative method is presented that is based upon the use of multiple headspace solid phase microextraction (HS-SPME) to monitor biogenic volatile organic compounds (BVOCs) released from a living leaf of Pelargonium hortorum in situ. Seventeen BVOCs were detected by GC-MS after a single SPME extraction using a CAR/DVB/PDMS fibre. An internal standard was employed to determine the absolute amounts of seven terpenoid compounds released from a P. hortorum leaf. The quantitative analysis was performed over two days, with extraction preformed for 20 min every 3 h. The amount of volatiles extracted varied with the time of day, with two maxima recorded at 14:00 (day 1) and 17:00 (day 2), corresponding to 236 and 277 ng of the seven terpenoids recorded, respectively. These results indicate that multiple HS-SPME in combination with an internal standard is a simple, quick, and quantitative technique for analysising BVOC emissions from a live plant sample.     

Novel Chiral Aminophosphine Ligand:Synthesis and Application in Saymmetric Catalytic Hydrogenation Reaction

A new chiral aminophosphine ligand 6,6′-dimethoxy-2,2′-bis(diphenylphosphinoamino)biphenyl(DMBDPPABP) was prepared and its rhodium complex was found to be an effective catalyst for the asymmetric hydrogenation of amidoacrylic acid and its dervatives.The effects of solvent and reaction temperature on enantioselectivity were also studied.     

Solution redox chemistry of carbon nanotubes

UV/vis/NIR absorbance spectra were used to monitor electron transfer between small-molecule redox reagents and carbon nanotubes (CNTs). The oxidation of (6, 5)-enriched nanotubes in water with K(2)Ir(Cl)(6) reveals a valence electron density of 0.2-0.4 e(-)/100 carbon atoms and a reduction potential of approximately 800 mV versus NHE. The reduction potential of CNTs is found to increase with increasing band gap and to decrease with the introduction of an anionic dispersant. In light of this newly revealed redox chemistry of CNTs, we propose that the previously observed bleaching of the CNT absorbance spectrum at low pH is most likely a consequence of the oxidation of the nanotubes by oxygen. These results demonstrate facile oxidation and reduction of CNTs, provide a way to quantify the population of valence electrons, and point to possible applications of CNT in the catalysis of redox reactions.