Palladium-catalyzed cross-coupling of benzylzinc reagents with 2-bromo-3,3,3-trifluoropropene

α-Trifluoromethyl alkenes can be used as peptide isosteres, moreover, the pre-installed vinyl group make it possible that transformation to diverse fluorine-containing unities. However, the cross-coupling of benzyl group with α-trifluoromethyl alkenes has yet to be developed. In this report, we describe a general method for the cross-coupling of benzylzinc reagents with 2-bromo-3,3,3-trifluoropropene (BTP) to afford diverse α-trifluoromethylalkene derivatives by using Pd(TFA)₂ as catalyst. This method takes advantage of cheap industrial available fluorine building blocks and easily prepared benzylzinc reagents to generate α-trifluoromethylalkene derivatives, which features with mild reaction conditions, wide substrate scope and feasibility of product transformations.     

Copper‐catalyzed asymmetric 1,4‐conjugate addition of dialkylzinc to enones

Asymmetric 1,4‐conjugation addition of dialkylzinc (diethylzinc and dimethylzinc) to cyclic enones, chalcone and nitroalkenes was achieved by a 25 mol% (R)‐6,6′‐Br₂‐BINOL( 1f ), 25 mol% CuSPh and 100 mol% dicyclohexylmethylamin(Cy₂NMe) catalyst system. The Cu(I) catalyst system enables the cyclic enone, chalcone and nitroalkene generality with high enantioselectivity (up to 84% ee) and isolated yield (up to 94%) under mild reaction conditions. Copyright © 2010 John Wiley & Sons, Ltd.     

Different crystal structures and luminescent properties of zinc and cadmium coordination polymers constructed from two flexible thioether ligands with different alkyl chains

Treatments of nitrogen-containing heterocyclic dithioether ligands, 1,2-bis(4-(pyridin-3-yl) pyrimidin-2-ylthio) ethane (L¹) and 1,3-bis (4-(pyridin-3-yl) pyrimidin-2-ylthio) propane (L²), with zinc or cadmium salts have resulted in the interesting frameworks with structural motifs from a mononuclear macrocycle or a dinuclear macrocycle to an one-dimensional structure. A small difference of the alkyl length between L¹ and L² led to conspicuous changes of the fluorescent properties of both ligands and their complexes. Mainly due to the size of metal atoms, structures of [ZnL²I₂] (1) and [CdL²I₂] (2) are varied from a mononuclear macrocycle to a 1D framework, while {[ZnL²(H₂O)₄](ClO₄)₂}₂ (3) and {[CdL²(H₂O)₄](ClO₄)₂}₂ (4) are dinuclear macrocycles in which perchlorate anions may play an important template role. As for complexes 5–8 ([ZnL¹I₂]_n (5), [CdL¹I₂]_n (6), {{[ZnL¹₂(H₂O)₄](ClO₄)₂}_0.5 · L¹_0.5 · CH₃OH} (7), {{[Cd_0.5L¹(H₂O)₂](ClO₄)}₂ · CH₃OH · L¹} (8)), the self-assemble processes were mainly directed by the organic ligand in the reactions of L¹ with metal salts. Complexes 1–4 exhibit blue fluorescence emissions, among which 1 and 2 may be suitable as candidates for blue fluorescent materials.     

Biomedical significance of endothelial cell specific growth factor, angiopoietin

Until recently, vascular endothelial growth factor (VEGF) was the only growth factor proven to be specific and critical for blood vessel formation. Other long-known factors, such as the fibroblast growth factors (FGFs), platelet-derived growth factor, or transforming growth factor-beta, had profound effects in endothelial cells. But such factors were nonspecific, in that they could act on many other cells, and it seemed unlikely that these growth factors would be effective targets for treatment of endothelial cell diseases. A recently discovered endothelial cell specific growth factor, angiopoietin, has greatly contributed to our understanding of the development, physiology, and pathology of endothelial cells (Davis et al., 1996; Yancopoulos et al., 2000). The recent studies that identified and characterized the physiological and pathological roles of angiopoietin have allowed us to widen and deepen our knowledge about blood vessel formation and vascular endothelial function. Therefore, in this review, we describe the biomedical significance of these endothelial cell growth factors, the angiopoietins, in the vascular system under normal and pathological states.     

氯离子柱撑水滑石共沉淀法合成反应动力学

根据氯离子型层状复合氢氧化物(LDH-Cl)制备过程中溶液浓度变化的监测结果和不同反应进程时产物的EDS、IR、XRD、TEM、TG-DTA表征结果,研究了合成LDH-Cl的共沉淀反应动力学特征及机理.实验结果表明, LDH-Cl的生成符合多核层表面反应动力学模型;反应过程中LDH的晶胞参数c从2.421 nm变为2.399 nm,通道高度h由0.3321 nm减小为0.3228 nm,粒子直径Da由6.40 nm增大为15.16 nm, Dc由7.43 nm增大到10.93 nm,纵横比由0.86增大为1.39; IR和TG-DTA特征变化表明了层板对阴离子作用的强度和层板的结构稳定性随反应进程而提高.     

Synthesis and Adsorption Property of Two Polymeric Adsorbents with Pendent Ether Bonds

Two polymeric adsorbents, poly(methyl p-vinylbenzvl ether) and oolv(ohenvl p-vinylbenzyl ether), were synthesized from chloromethylated polystyrene, Their adsorptionproperty for phenol in hexane solution was investigated. The results showed that the twoadsorbents adsorb phenol from hexane solution through hydrogen-bonding and π-π stacking interaction.     

Kinetics of 2‐Propanol Dehydration over Montmorillonite Clays and Pillared Montmorillonites

Metal ion exchanged montmorillonites (AlM & CrM) and metal oxide pillared montmorillonite (AlPM & CrPM) were prepared and characterized with XRD, FT‐IR, nitrogen adsorption and TPD of ammonia. The pillaring process results in a remarkable increase of interlayer distance, surface area and acid amount of the catalyst. However, increasing the calcined temperature causes reverse effects for the CrPM catalyst. The acid amount decreases in the order of CrPM200 < CrPM300 < AlPM500 < CrM < CrPM400 ≥ CrPM500 ≥ AlM. In the dehydration of 2‐propanol to propene, the reaction follows first order kinetics and the apparent rate constant is related to the catalyst acid amount. Compensation effect occurs in this reaction over the series of catalysts.     

还原席夫碱型三角架式金属配合物的合成和性质研究

由2，2，′，2＂-三氨基三乙胺(tren)与N-氧化吡啶醛经席夫碱型缩合，然后还原C=N双键形成的产物为配体(L¹)，合成了一系列新三角架式过渡金属配合物：［ML¹］²⁺［M=Mn(Ⅱ)、Ni(Ⅱ)和Zn(Ⅱ)］。利用元素分析、红外光谱、电子光谱和室温磁化率对配合物的结构和性质进行了研究。