Macrocyclic Polysiloxane Immobilized Ligand System and Its Structural Characterization

A new porous solid macrocyclic 1,4,7,10,14,17,20‐heptaazadocosane‐3,21‐dione polysiloxane ligand system of the general formula P‐(CH₂)₃‐C₁₅H₃₂O₂N₅, (where P represents [Si‐O]n siloxane network) has been prepared by the reaction of immobilized iminobis(N‐diethylenediamineacetamide)polysiloxane with 1,3 dibromopropane. The new macrocyclic polysiloxane ligand system exhibits high potential for the uptake of metal ions (Fe³⁺, Co²⁺, Ni²⁺, Cu²⁺ and Zn²⁺). Complexation with copper ions exhibits a high selectivity in which two copper ions were involved per one macrocyclic ligand group.     

Synthesis of New Polysiloxane-Immobilized Ligand System Di(amidomethyl)aminetetraacetic Acid

A new chelating porous polysiloxane-immobilized tetraacetic acid ligand system has been prepared. This material was made by chemical modification of the iminodiacetic acid polysiloxane with thionyl chloride and diethyliminodiacetate, respectively. The polysiloxane functionalized with di(amidomethyl)aminetetraacetic acid of the general formula P-(CH ₂ ) ₃ N(CH ₂ C(O)N) ₂ (CH ₂ COOH) ₄ [where P represents the polysiloxane backbones (Si?O?Si) _n ] was characterized by Thermogravimetric Analysis (TGA) and FTIR spectra. The FTIR results proved that tetraacetic acid groups are successfully grafted onto the polysiloxane surface. This ligand system exhibits high potential for extraction of divalent metal ions (Co⁺², Ni⁺², Cu⁺², and Zn⁺²) from aqueous solution.     

Synthesis and characterization of polyimide‐polysiloxane segmented copolymers for fuel cell applications

Sulfonated polyimides exhibit high strength, good film‐forming ability, chemical resistance, and, in their hydrated state, relatively high proton conductivity. Here we report the one‐pot synthesis of sulfonated polyimide‐polysiloxane segmented copolymers through the reaction of a dianhydride with a mixture of three diamines: a nonionic aromatic diamine (4,4′‐oxydianiline), a sulfonated diamine (4,4′‐diamino‐2,2′‐biphenyldisulfonic acid), and a telechelic diamino polysiloxane. Copolymer compositions were evaluated using ¹H NMR and size‐exclusion chromatography. The presence of ion‐containing diamines in the reaction mixture inhibited stoichiometric incorporation of hydrophobic siloxane segments. Siloxane segments were found to lower the thermal stability of the polyimide host. Copolymers with and without siloxane segments were cast into free‐standing films. Equilibrium water sorption studies of cast films show that, for the compositions studied here, the presence of siloxane segments does not interfere with water swelling, suggesting that a microphase‐segregated morphology may exist. TEM and SAXS analyses show evidence of phase‐segregation in sulfonated polyimides and reveal that siloxane segments strongly affect ionic clustering. However, proton conductivity only changes slightly when polysiloxane segments are incorporated. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3747–3758, 2007     

New Strategy for the Synthesis of Diethylenetriaminetetraacetic Acid Functionalized Polysiloxane Ligand Systems

A new rout was used for the synthesis of porous solid polysiloxane matrix of the general formula P-(CH₂)₃N(CH₂COOEt)-(CH₂)₂N(CH₂COOEt)-(CH₂)₂-N(CH₂COOEt)₂ (where P represents [Si-O]_n) by the reaction of diethylenetriaminetrimethoxysilane with ethyl chloroacetate followed by polymerization with tetraethylorthosilicate via the sol gel process. The functionalized diethylenetriaminetetraacetic acid polysiloxane system (P-DETATA) was then obtained by acid hydrolysis of the diethylenetriaminetetraethylacetate functionalized polysiloxane(P-DETATAc). FTIR, ¹³C, ²⁹Si CP-MAS NMR and XPS methods were used for characterization of their chemical structure. The new functionalized ligand system exhibits high capacity to coordinate with divalent metal ions (Co²⁺, Ni²⁺, and Cu²⁺) than its analogous ligand obtained by postmodification of triamine polysiloxane with ethyl chloroacetate.     

Synthesis of Polysiloxane-Immobilized Monoamine,Diamine, and Triamine Ligand Systems in the Presence of CTAB and Their Applications

Abstract

Polysiloxane-immobilized monoamine, diamine, and triamine ligand systems of the general formula P-(CH₂)₃-X [where P represents a polysiloxane three-dimension silica like network, and X represents monoamine(-NH₂), diamine (-NH(CH₂)₂NH₂), or triamine (-NH(CH₂)₂NH(CH₂)₂NH₂) functional ligand groups] were prepared by hydrolytic polycondensation of the tetraethylorthosilicate (TEOS) and the appropriate amine silane coupling agent (RO)₃Si-(CH₂)₃X in the presence of cetyltrimethylammonium bromide (CTAB) as surfactant using the sol-gel method. The polysiloxane-immobilized amine ligand systems exhibit a higher potential for divalent metal ions (Cu²⁺, Ni²⁺, Co²⁺) when CTAB was used as surfactant than those of the corresponding polysiloxane ligand systems prepared without CTAB. X-ray Photoelectron Spectroscopy (XPS) analyses show a significant change in the surface composition as resulting from the incorporation of CTAB, which can be related to the increase in the uptake of metal ions.     

Synthesis,Characterization and Applications of Immobilized Iminodiacetic Acid-Modified Silica

Porous immobilized iminodiacetic acid modified silica of the general formula S—(CH₂)₃—N(CH₂COOH)₂, (where S represents [Si—O] _n siloxane network) has been prepared by replacement of the iodide in 3-iodopropyl modified silica with diethyliminodiacetate. The immobilized-diethyliminodiacetate ligand system (S-DIDA) was then hydrolyzed by hydrochloric acid to produce the immobilized iminodiacetic acid ligand system (S-IDA). The iodo functionalized modified silica (S-I) was prepared by polycondensation of Si(OEt)₄ and (MeO)₃Si(CH₂)₃I. The XPS and CP/MAS ¹³C NMR spectra showed that not all iodine atoms are replaced and that the hydrolysis of ethyl acetate groups are incomplete upon treatment with HCl. The immobilized iminodiacetic acid ligand system exhibits high potential for the uptake of various di- and trivalent metal ions such as (Mn²⁺, Fe³⁺, Co²⁺, Ni²⁺, Cu²⁺ and Zn²⁺). Complexation of the iminodiacetate ligand system for the metal ions at the optimum conditions was found in the order: Cu²⁺ > Fe³⁺ > Ni²⁺ > Co²⁺ > Mn²⁺ > Zn²⁺. Stability studies of the iminodiacetate ligand system showed that a degradation of the siloxane network and leaching of some species occurred upon treatment with strong acid and base aqueous solutions.     

Cyclosiloxane‐based networks: Synthesis,thermal characterization,and microstructure

This article mainly concerns the synthesis of novel PD₅/PDMS conetworks by the copolymerization of cyclic D₅H and linear HO? PDMS? OH units, and the characterization of the product by DMTA, DSC, and TGA. The ultimate properties of the conetworks may be controlled by varying the relative composition of D₅H and PDMS components. DMTA and DSC thermograms indicate compatibility between the PD₅ and PDMS domains. Understanding of the polymer chemical transformations involved in conetwork formation combined with an analysis of DMTA and DSC thermograms led to a proposition of the microarchitecture of PD₅/PDMS conetworks. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 630–637, 2005     

Uptake of Divalent Metal Ions (Cu2+, Zn2+ and Cd2+) by Polysiloxane Immobilized Glycinate Ligand System

ABSTRACT

Porous solid siloxane polymer carrying glycinate functional group of formula –(CH₂)₃NHCH₂COOH has been prepared by the sol-gel process. Treatment of aqueous solutions of divalent metal ions with the polysiloxane glycinate ligand system demonstrates that this material exhibits high potential for preconcentration of metal ions (Cu²⁺, Zn²⁺ and Cd²⁺). The ligand system chemisorbs these divalent metal ions, at optimum conditions, in the order: Cd²⁺ < Zn²⁺ < Cu²⁺. The uptake of copper ions is concentration dependent but it is independent on the presence of other competing ions. Treatment of the glycinate ligand system with acidic solution results in leaching of bound ligands. The highest leaching occurs in presence of copper ions at low pH     

Uptake of Divalent Metal Ions (Cu2+, Zn2+ and Cd2+) by Polysiloxane Immobilized Monoamine Ligand System

ABSTRACT

Porous solid siloxane polymers carrying a monoamine functional group of formula P-(CH₂)₃NH₂ (Where P- represents a siloxane framework silica like ) has been prepared by polycondensation of Si(OEt)₄ and (MeO)₃Si(CH₂)₃-NH₂. Treatment of aqueous solutions of divalent metal ions with the polysiloxane monoamine ligand system demonstrates that this material has high potential for preconcentration of metal ions (Cu²⁺, Zn²⁺ and Cd²⁺). The tendency of these divalent metal ions to chemisorb by the monoamine ligand system at the optimum conditions increases in the order: Cd²⁺ <Zn²⁺ <Cu²⁺. The optimum pH is 5.5 for copper and 6-7 for zinc and cadmium. The ammonia/ ammonium chloride buffer solution gave maximum uptake for all metal ions. It is also found that the uptake of copper ions is concentration dependent and is independent of the presence of other competing ions. The monoamine ligand system suffers from leaching of ligand containing groups upon treatment with acidic solutions. The highest leaching occurs at low pH.     

侧链可降解聚硅氧烷的合成及其膜性能

以乳酸和聚乙二醇为原料,直接缩聚法制备出聚乳酸-聚乙二醇可降解嵌段共聚物,再将烯丙基缩水甘油醚和所得的嵌段共聚物在锌粉的作用下得到带有α烯基反应性官能团的大分子单体,然后在铂催化剂的作用下,合成了一种带有可降解侧链的亲水性聚硅氧烷(PDMS-g-PLA-PEG).对产物的结构、相对分子质量及其分布、热性能及成膜的表面性能等进行了研究.结果表明,由于分子链中硅氢键分布的不均匀性和聚乳酸-聚乙二醇共聚物分子量分布的不均一性,产物的分子量分布相对较宽,达到了1.87.由于聚乳酸-聚乙二醇共聚物侧链逐渐降解,所以PDMS-g-PLA-PEG所成的膜与水的接触角将随着时间的延长而逐渐增大,30天后从42°增至92°.     

Synthesis and Applications of a New Polysiloxane-Immobilized Macrocyclic Ligand System

Abstract

Insoluble porous solid, macrocyclic 22-membered ring, 1-oxa-6,9,12,15,18-pentaaza-2,22-disilacyclododocosane polysiloxane ligand system has been prepared by the reaction of a macro-silane agent with tetraethylorthosilicate. The macro-silane agent was prepared by the reaction of imino-bis(N-2-aminoethylacetamide) ligand with 3-iodopropyltrimethoxysilane in 1:3 molar ratio. The new prepared polysiloxane system exhibits variable potentials for the extraction of metal ions (Fe³⁺, Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺, Ag⁺, Cd²⁺, Hg²⁺, and Pb²⁺) from aqueous solutions. The ligand system shows high capacity to extract silver, lead, and mercury. Chemisorption of the metal ions by the ligand system at the optimum conditions was found in the order Ag ⁺ > Pb²⁺ > Hg²⁺ > Cu²⁺ > Ni²⁺ > Fe³⁺ > Co²⁺ > Cd²⁺ > Zn²⁺.     

Synthesis of organofunctionalized polysiloxane from polymeric tributylstannyl ester of silicic acid and chlorosilanes

Polymeric tributylstannyl ester of silicic acid (PTBS) was demonstrated to be an effective material for the preparation of functionalized polysiloxane derivatives (2). The reaction of PTBS and monochlorosilane (1), which possessed an organofunctional group such as the acetoxy or methylmethacrylate group, proceeded readily at room temperature under neutral conditions to give 2 with the elimination of the tributyltin group. The molecular weight of 2 estimated by GPC measurement was almost the same as that of starting PTBS. Such metal-exchange reaction was applicable for the incorporation of two kinds of silyl units into polysiloxane 2 by employing these monochlorosilanes 1 at the same time in the reaction. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 2363–2369, 1999     

Preparation,characterization and application of polyaniline/epoxide polysiloxane composite films

Composites of polyaniline(PAn) and epoxide polysiloxane(EPSi) are reported for the first time. EPSi is designed, synthesized and N-grafted onto the PAn backbone through covalent bonds. As-prepared EPSi-g-PAn composites are soluble in organic solvents and the corresponding films can be easily produced via a simple solution-casting procedure. The composite films combine the mechanical characteristics of EPSi and the chemical properties of PAn, enabling the facile introduction of the noble metal particles. The successful fabrication of the composites is confirmed by the investigation of the molecular structure, crystalline structure and microstructure of the materials. The resulting composite films containing noble metal particles are employed as the catalysts for the hydrogenation of phenol to produce cyclohexanone, which exhibit the convenience and recyclability for usage as well as the high catalytic activities, including the conversion ratio of 97%-100% and the selectivity as high as 84%-98%. The present work not only provides a new method to improve the processability of the conducting polymers but also describes a kind of composite materials that may display outstanding preformances in industrial catalysis.     

新有机试剂4-(2-苯并噻唑偶氮)焦棓酚的合成、性能和分析应用

本文以2-氨基苯并噻唑为原料,经重氮化后与焦棓酚偶联合成了4-(2-苯并噻唑偶氮)焦棓酚,用乙醇重结晶精制。并用元素分析、波谱等鉴定了结构。测定了其离解常数和质子化常数。研究了该试剂的一般性质、多配位显色反应,发现其与Mo(Ⅵ)、W(Ⅵ)、Ti(Ⅳ)等的显色反应在CTMAB和CPB等阳离子表面活性剂存在下有高的灵敏度。     

Synthesis and characterization of titanium and zirconium complexes with silicone-bridged phenoxycyclopentadienyl ligands

Dimethylsilyl(2,3,4,5-tetramethylcyclopentadienyl)(3-tert-butyl-5-methyl-2-phenoxy)titanium dichloride (1a), a useful catalyst precursor for olefin copolymerization, was synthesized at high yield starting from allyl-protected phenolic ligand 3a,which was first treated with 2 equiv. of n-BuLi to selectively give the dilithium salt of 3a along with 1-heptene, a coupling product of a protected allyl ether moiety and butyl anion. Addition of TiCl₄ to the resulting dilithium salt of 3a in toluene afforded 1a in 50% isolated yield. This methodology could be applied to the preparation of related titanium and zirconoium complexes 1b-1d, 8 with silicone-bridged Cp-phenoxy ligands, whereas the reaction starting from methyl-protected precursor 2a did not produce the zirconium complex 8. Copolymerization of ethylene and 1-hexene with the newly prepared complexes was also investigated.     

Preconcentration and Separation of Copper(II) by 3-Aminopropylpolysiloxane Immobilized Ligand System

Porous solid insoluble polysiloxane-immobilized ligand system bearing propylamine of the general formula P-(CH₂)₃-NH₂ (where P represents [Si–O]_n siloxane network) was prepared and evaluated for the separation and preconcentration of copper(II) from aqueous solution. The ligand system retained Cu(II) effectively when used as a metal ion extractant. The ligand system also showed high selectivity to separate copper(II) from a mixture of metal ions (Co(II), Ni(II), Cu(II)) when used as chromatographic stationary phase. The optimum pH appeared to be pH = 5.5 using acetate buffer as an eluent. Thermal analysis showed that the ligand system is very stable at relatively high temperatures.     

Synthesis,structural characterization,and olefin polymerization behavior of vanadium(III) complexes bearing bidentate phenoxy‐phosphine ligands

Vanadium(III) complexes bearing phenoxy‐phosphine ligands ( 2a–g ) (2‐R₁‐4‐R₂‐6‐PPh₂‐C₆H₂O)VCl₂(THF)₂ ( 2a : R₁ = R₂ = H; 2b : R₁ = F, R₂ = H; 2c : R₁ = Ph, R₂ = H; 2d : R₁ = tBu, R₂ = H; 2e : R₁ = R₂ = Me; 2f : R₁ = R₂ = tBu; 2g : R₁ = R₂ = CMe₂Ph) were prepared from VCl₃(THF)₃ by treating with 1.0 equiv of the ligand in tetrahydrofuran (THF) in the presence of excess triethylamine (TEA). The reaction of VCl₃(THF)₃ with 2.0 equiv of the ligand in THF in the presence of excess TEA afforded vanadium(III) complexes bearing two phenoxy‐phosphine ligands ( 3c–f ). These complexes were characterized by FTIR and mass spectrum as well as elemental analyses. Structures of 2f and 3c were further confirmed by X‐ray crystallographic analyses. Complexes 2a–g and 3c–f were employed as the catalysts for ethylene polymerization under various reaction conditions. On activation with Et₂AlCl, these complexes exhibited high catalytic activities (up to 41.3 kg PE/mmol_V·h·bar) even at high temperature (70°C), and produced high molecular weight polymer with unimodal molecular weight distributions, indicating the polymerization took place in a single‐site nature. Complexes 3c–f displayed better thermal stability than the corresponding complexes 2a–g under similar conditions. In addition, copolymerizations of ethylene and 1‐hexene with precatalysts 2a–g were also explored in the presence of Et₂AlCl. Catalytic activity, comonomer incorporation, and properties of the resultant polymers can be controlled over a wide range by tuning catalyst structures and reaction parameters.© 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

三个二羧酸配体配位聚合物的合成、结构表征和荧光性质

以羧酸配体2,2''-（1,4-亚苯基双（亚甲基））双（硫二基）二苯甲酸（H₂L¹）和2,2''-（2,3,5,6-四甲基-1,4-亚苯基）双（亚甲基）双（硫二基）二苯甲酸（H₂L²）分别与金属盐反应,通过溶剂热方法合成了3个配位聚合物：{[Ni（L¹）（H₂O）₄]·2H₂O}_n （1）、[Zn（L¹）（DMA）₂]_n （2）和[Co（L²）（DMF）₂]_n （3）,其中DMA=N,N-二甲基乙酰胺,DMF=N,N-二甲基甲酰胺。对配合物1~3进行了单晶X射线衍射、元素分析、红外光谱、热重分析、粉末X射线衍射和固体紫外可见光谱测试和表征。单晶X射线衍射表明：3个配合物均为一维锯齿形链状结构,并通过氢键作用形成三维骨架,且配体均表现为反式构象。此外,对配合物2固态荧光性质进行了研究。     

三个二羧酸配体配位聚合物的合成、结构表征和荧光性质

以羧酸配体 2,2''-(1,4-亚苯基双(亚苯基))双(硫二基)二苯甲酸(H₂L¹)和 2,2''-(2,3,5,6-四甲基-1,4-亚苯基)双(亚甲基）双(硫二基)二苯甲酸(H₂L²)分别与金属盐反应,通过溶剂热方法合成了 3个配位聚合物：{[Ni(L¹)(H₂O)₄]·2H₂O}_n (1)、[Zn(L¹)(DMA)₂]_n(2)和[Co(L²)(DMF)₂]_n (3),其中DMA=N,N-二甲基乙酰胺,DMF=N,N-二甲基甲酰胺。对配合物1~3进行了单晶X射线衍射、元素分析、红外光谱、热重分析、粉末X射线衍射和固体紫外可见光谱测试和表征。单晶X射线衍射表明：3个配合物均为一维锯齿形链状结构,并通过氢键作用形成三维骨架,且配体均表现为反式构象。此外,对配合物2固态荧光性质进行了研究。