Synthesis,characterization and biological activity of a novel binuclear organotin complex,Ph3Sn(HL)·Ph2SnL [L = 3,5‐Br2‐2‐OC6H2CHNCH(i‐Pr)COO]

A 1:1 reaction of triphenyltin chloride with potassium N‐[(3,5‐dibromo‐2‐hydroxyphenyl)methylene] valinate in benzene under reflux leads to the formation of a novel mixed organotin binuclear complex, Ph₃Sn(HL)·Ph₂SnL [L = 3,5‐Br₂‐2‐OC₆H₂CH?NCH(i‐Pr)COO], by means of a facile phenyl–tin bond cleavage process. The X‐ray structure reveals that there are two distinct types of carboxylate coordination mode and trans‐O₂SnC₂N and trans‐O₂SnC₃ in distorted trigonal bipyramidal geometries. The complex displays good in vitro cytotoxicity and antibacterial activities. Copyright © 2005 John Wiley & Sons, Ltd.     

含羧酸共生稀土光敏剂的低密度聚乙烯膜紫外光氧化降解

含羧酸共生稀土光敏剂的低密度聚乙烯膜紫外光氧化降解林宜超（福建省测试技术研究所福州３５０００３）近年来，许多作者先后研究并开发出含硬脂酸铈（ＣｅＳｔ３）光敏剂的可控光降解低密度聚乙烯（ＬＤＰＥ）［１，２］、高密度聚乙烯［３］、聚丙烯［４］、聚苯乙烯...     

Synthesis of isomerically pure carboxylate- and sulfonate-substituted xanthene fluorophores

Xanthene-based fluorophores such as fluorescein and rhodamine are typically prepared by acid-catalyzed condensation of the appropriate resorcinol or 3-aminophenol with phthalic anhydride. Condensation of substituted phthalic anhydride species results in functionalized fluorophores that are formed as mixed isomers. Crystallization approaches to isomer separation have been reported elsewhere for symmetric fluorescein carboxylates. We describe crystallization-based separation of protected fluorescein sulfonates and coupling conditions to form sulfonamides, precursors for carboxylate-substituted rhodamines, and precursors for asymmetrically substituted fluoresceins and rhodafluors.     

Synthesis and Crystal Structure of a Heteropentanuclear Yb(Ⅲ)-Cu (Ⅱ) Complex:[Yb_2Cu_3(O_2CCH_2CI)_(12)(H_2O)_8]·2H_2O

1INTRODUCTIONInterestinpolynuclearcomplexesisstimulatedbytherolestheyplayindifferentfields,e.g.heterogeneouscatalysis,bioinorganicchemistryandthedesignofmagneticmaterials.Since1985ill,considerableattentionshavebeengiventomolecularcomplexest'isimultaneouslycomprisingdandfmetalionsduetotheirspecialmagneticproperties.Coupledpolyr^uclearsystemscontaining3delementshavebeenextensivelyinvestigatedL,3,butonlyafew,derivedfromcarboxylatesL4--63,thatcontainbothtransitionandrare--earthmetalionshavebe…     

Kinetic study on effect of novel cationic dimeric surfactants for the cleavage of carboxylate ester

Kinetic study has been performed to understand the reactivity of novel cationic gemini surfactants viz. alkanediyl‐α,ω‐bis(hydroxyethylmethylhexadecylammonium bromide) C₁₆‐s‐C₁₆ MEA, 2Br^? (where s = 4, 6) in the cleavage of p‐nitrophenyl benzoate (PNPB). Novel cationic gemini C₁₆‐s‐C₁₆ MEA, 2Br^? surfactants are efficient in promoting PNPB cleavage in presence of butane 2,3‐dione monoximate and N‐phenylbenzohydroxamate ions. Model calculation revealed that the higher catalytic effect of ethanol moiety of gemini surfactants (C₁₆H₃₃N⁺ C₂H₄OH CH₃ (CH₂)_S N⁺ C₂H₄OH CH₃C₁₆H₃₃, 2Br^?, s = 4, 6) is due to their higher binding capacity toward substrate. This is in line with finding that binding constants for novel series of cationic gemini surfactants are higher than conventional cationic gemini (C₁₆H₃₃N⁺(CH₃)₂(CH₂)_SN⁺(CH₃)₂C₁₆H₃₃, 2Br^?, s = 10, 12), cetyldimethylethanolammonium bromide and zwitterionic surfactants, i.e. C_nH_2n+1N⁺Me₂ (CH₂)₃ SO₃^? (n = 10; SB3‐10). The fitting of kinetic data was analyzed by the pseudophase model. Copyright © 2013 John Wiley & Sons, Ltd.     

New oxacalix[4]arene carboxylate detects viologen in protic media

ABSTRACT

We demonstrate that Ullman fragment-coupling can be used to synthesise an oxacalix[4]arene monocarboxylic acid, which provides easy access to its water-soluble carboxylato derivatives. Crystallographic and computational data suggest that the new carboxyl-substituted oxacalix[4]arene adopts a 1,3-alternate conformation both in the solid-state and in methanol solution. Its water-soluble tetrabutylammonium derivate can detect the herbicide paraquat at neutral pH in aqueous media (K _a = 111 ± 3 M^–1) and in methanol (K _a = 2020 ± 70 M^–1).     

Catalytic Behavior of Mono-N-Protected Amino-Acid Ligands in Ligand-Accelerated C−H Activation by Palladium(II)

Mono-N-protected amino acids (MPAAs) are increasingly common ligands in Pd-catalyzed C−H functionalization reactions. Previous studies have shown how these ligands accelerate catalytic turnover by facilitating the C−H activation step. Here, it is shown that MPAA ligands exhibit a second property commonly associated with ligand-accelerated catalysis: the ability to support catalytic turnover at substoichiometric ligand-to-metal ratios. This catalytic role of the MPAA ligand is characterized in stoichiometric C−H activation and catalytic C−H functionalization reactions. Palladacycle formation with substrates bearing carboxylate and pyridine directing groups exhibit a 50–100-fold increase in rate when only 0.05 equivalents of MPAA are present relative to Pd^II. These and other mechanistic data indicate that facile exchange between MPAAs and anionic ligands coordinated to Pd^II enables a single MPAA to support C−H activation at multiple Pd^II centers.     

有机锡5-甲基/氨基-1H-四唑乙酸酯的合成、结构与抗肿瘤活性

通过5-甲基/氨基-1H-四唑乙酸与（R₃Sn）₂O（R为苯基或正丁基）及三环己基氢氧化锡的反应,合成了5个三有机锡5-甲基/氨基-1H-四唑乙酸酯。通过核磁,红外及X射线单晶衍射分析,对这些化合物进行了详细的结构表征。结果表明,这些化合物往往通过分子间的Sn…N作用形成配位高分子。初步的生物活性测试表明,这些配合物对Hela和A549细胞具有明显的体外细胞毒性。