Speier's Catalyst Research Articles

Fabrication of bisferrocenyl derivative grafted HTPB with high iron content and its application in dopamine detection

In this work, we employed an efficient strategy to increase the graft percentage of ferrocene in hydroxyl terminated polybutadiene (HTPB) polymer framework. For this purpose, we use 5-chloro-2-pentanone to attach the two alkylferrocene derivatives to each other. In order to incorporate the obtained bis-alkylferrocene derivatives to the polymer backbone, the chlorine atom at the end of the coupling agent alkyl chain was converted to a silane group using the Grignard reaction. Finally, hydrosilylation reaction of as-synthesized silane derivatives and HTPB in the presence of Speier's catalyst (H2PtCl6) resulted in novel bis-ferrocene modified HTPBs with a variety of iron contents. The iron percentage, viscosity, and glass transition temperature of the novel bis-ferrocene modified HTPBs as essential parameters of polymer characterization were investigated. Obtained polymers are electro-active due to the presence of ferrocenyl groups. Additionally, unlike the virgin polymer (HTPB) they show optical properties. The final polymer was immobilized onto the bare glassy carbon electrode (GCE) surface using the cross-linking effect of terephthaldehyde (TFA) and fresh egg white (FEW). Electrochemical impedance spectroscopy (EIS) confirmed the successful immobilization of the polymer. The ability of the fabricated electrode to mediate dopamine (DA) oxidation was evaluated, and the results show the acceptable detection limits as well as linear ranges for the determination of dopamine using GC/BEFcHTPB/(TFA+FEW).

Synthesis & characterization of novel silicone dendrimers as base stock for high performance lubricants

The silicone core GI dendrimers having terminal Si-H groups reacted with maleic anhydride in presence of Speier's catalyst to afford anhydride terminated dendrimers. These anhydride dendrimers were further reacted with long chain aliphatic alcohols in presence of lower valent tin oxide as catalyst to synthesize novel second generation complete neutral silicone ester dendrimers. These high performance silicone esters dendrimers can be used for different avionic applications and also as base stock material for lubricants. Characterizations of the dendrimers were carried out by elemental analysis; Fourier transforms infrared spectroscopy (FT-IR) and proton nuclear magnetic resonance spectroscopy (1H NMR spectroscopy). Physical properties like density, viscosity, flash point and pour point of the dendrimers were also studied. Vapor pressure osmometery (VPO) and gel permeation chromatography (GPC) were used for measuring the molecular weight and molecular weight distribution of the dendrimers.

ChemInform Abstract: Synthesis and Cytotoxic Activity of 1‐{3‐[1‐(5‐Organylsilylfuran‐2‐yl)silinan‐1‐yl]propyl}amines and Some Trimethylgermyl Analogues.

AbstractSubstrates (III) are prepared following the method demonstrated for (IIIa).

Effects of the carboxyl‐ended hyperbranched polyester/platinum complex molecular weight on hydrosilylation activity and self‐assembled morphology

ABSTRACTResearch on platinum catalysts with high activity and long life for hydrosilylation has attracted a great deal of interest because of the increasing price of platinum metal. In this study, we examined the effect of the molecular weight of carboxyl‐ended hyperbranched polyester/platinum complexes (HTD‐n–Pt's, where n = 1, 2, 3, or 4) on hydrosilylation activity and self‐assembled morphology. Relevant parameters tuning the morphology of self‐assemblies, such as the temperature, time, concentration, and relative humidity, were examined. All of the HTD‐n–Pt's with various molecular weights had much higher hydrosilylation activities than did the conventional homogeneous Speier's catalyst, and the HTD‐n–Pt could be self‐assembled into ordered two‐dimensional treelike structures with a fractal dimension ranging from 1.48 to 1.83; this indicated perfect fractal properties. With the increase of the HTD‐n–Pt molecular weight, the size of the self‐assembled treelike structures and the catalytic activity increased first and then decreased. The self‐assembly mechanism was speculated and analyzed by dynamic light scattering, X‐ray photoelectron spectroscopy, X‐ray diffraction, scanning electron microscopy, and Fourier transform infrared spectroscopy; these suggested good agreement with the diffusion‐limited aggregation theory of particles. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41416.

Synthesis and cytotoxic activity of 1-{3-[1-(5-organylsilylfuran-2-yl)silinan-1-yl]propyl}amines and some trimethylgermyl analogues.

New highly cytotoxic 1-{3-[1-(5-organylsilyl-furan-2-yl)silinan-1-yl]propyl}amines and some trimethylgermyl analogues (IC50 1-7 μg mL(-1)) have been synthesized by a hydrosilylation reaction of aliphatic and heterocyclic N-allylamines in the presence of Speier's catalyst. The effects of the silacycle, the element-organic substituent in position 5 of the furan ring, and the structure of the amine on the cytotoxicity of the new compounds have been studied.

Carboxylic Acids Promoted Speier’S Catalyst for the Hydrosilylation of Styrene with Triethoxysilane: Activity, Selectivity, and Mechanism

Catalytic performances of Speier's catalyst with carboxylic acids were studied in the hydrosilylation reaction of styrene with triethoxysilane. The effect of carboxylic acids (RCOOH) with different pKa values and size was investigated, and the temperature and n(COOH)/n(Pt) ratios were also studied. The catalytic activity of the hydrosilylation reaction is related to the acid strength of the carboxylic acid, temperature, and n(COOH)/n(Pt) ratio, while the selectivity for the β-adduct is related to the size of carboxylic acid and the n(COOH)/n(Pt) ratio. Moreover, the influence of carboxylic acid on the hydrosilylation reaction was explained with the help of density functional theory calculations, and a reasonable mechanism was proposed.

Synthesis and Characterization of Carboxyl Terminated Polydimethylsiloxanes

A series of hydrogen terminated polydimethylsiloxanes (PDMS-H) had been controlled synthesized via ring-opening polymerization. Then, methylmethacrylate (MMA) and tert-butyl methacrylate (tBMA) were grafted to PDMS-H via hydrosilylation reactions in the presence of Speier's catalyst, the hydrosilylation addition patterns of MMA and tBMA showed a strong preference toward β-1,2 addition, no α-1,2 addition product or 1,4-addition product was observed. Carboxyl terminated polydimethylsiloxanes were prepared by subsequent hydrolysis reaction in an aqueous NaOH/ethanol solution and under acid condition, respectively. Both methods could obtain carboxyl terminated polydimethylsiloxanes successfully. However, a significant decrease of the molecular weight of products was observed in the alkaline hydrolysis process, while the acid hydrolysis of tertiary butyl ester group terminated polydimethylsiloxanes could be conducted in a highly controlled manner. Besides, the synthesis of carboxyl terminated polydimethylsiloxanes via acid hydrolysis reaction can be conducted well only when the terminal group of polydimethylsiloxanes is tertiary butyl, this can be explained by the specificity of tertiary butyl.

Synthesis, structure and cytotoxicity of new 2‐[(3‐aminopropyl)dimethylsilyl]‐5‐furfural diethylacetals and 2‐[(3‐aminopropyl)dimethylsilyl]‐5‐phenylfurans

Novel 2‐[(3‐aminopropyl)dimethylsilyl]‐5‐furfural diethylacetals and 2‐[(3‐aminopropyl)di‐methylsilyl]‐5‐phenylfurans have been synthesized by a hydrosilylation reaction of aliphatic and heterocyclic N‐allylamines in the presence of the Speier's catalyst. The effects of the structure of the amine and nature of organic substituent at the furan ring on the cytotoxicity of the new compounds have been studied. Copyright © 2013 John Wiley & Sons, Ltd.

Synthesis and antitumor activity of 3-[(methyl)bis(5-trialkylsilyl-furan-2-yl)silyl]propylamines

Novel 3-[(methyl)bis(5-trialkylsilylfuran-2-yl)silyl]propylamines have been synthesized by a hydrosilylation reaction of aliphatic and heterocyclic N-allylamines in the presence of the Speier's catalyst. The effects of the structure of the amine and the alkyl substituent at the silicon atom on the cytotoxicity of the compounds have been studied.

Synthesis of new calix[4]arenes bearing silylether groups

The Si-H groups of 25,26,27,28-tetrakis[4-(tris(dimethylsilyl)methyl)butoxy]calix[4]arene (II) were treated with methanol, ethanol, propanol, butanol, pentanol, hexanol, isopropanol, 1-methyl propanol, 2-methylpropanol and 2-chloroethanol in the presence of Karstedt catalyst (platinum(0)-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex, solution in xylene) to give the corresponding 25,26,27,28-tetrakis[4-(tris(alkoxydimethylsilyl)methyl)butoxy]calix[4]arene. It is found that alcoholysis of calix[4]arene 1 in the presence of Speier catalyst (H2PtCl6.6H2O) was unsuccessful using reflux conditions over seven days. In addition, the rate of alcoholysis is dependent on the amounts of the catalyst and reaction temperature.

Effect of catalysts on the reaction of allyl esters with hydrosilanes

The reaction of hydrosilylation of allyl esters XOCH2CH=CH2 (X = MeCO, CF3CO, C3F7CO) and PhOCH2CH=CH2 with hydrosilanes HSiY3 (Y = Cl, OEt) in the presence of the Speier catalyst, the Speier catalyst with additives, and of various nickel complexes was studied. The catalytic hydrosilylation reaction in the presence of the Speier catalyst is accompanied by the reduction. Additives to the Speier catalyst (vinyltriethoxysilane and some ethers) allow to suppress considerably the reduction reaction. In the presence of the studied nickel complexes mainly reduction and isomerization reactions occurred. The best nickel catalysts of hydrosilylation were the mixtures of NiCl2 or Ni(acac)2 with phosphine oxides. In contrast to allyl esters, the hydrosilylation of simple olefins proceeds easier, the content of the product of hydrosilylation in the reaction mixture reaches 94.3%.

Studies on the synthesis and thermal properties of alkoxysilane‐terminated organosilicone dendrimers

AbstractSilicone core dendrimers bearing terminal dialkoxy and trialkoxy silane groups were prepared in a three‐step synthesis. Initially, the SiH terminated multifunctional silicone dendrimer, i.e. tetrakis(dimethylsiloxy)silane, was prepared by the reaction of tetraethoxysilane and dimethylethoxysilane. Tetrakis(dimethylsiloxy)silane on reaction with allylglycidylether in the presence of Speier's catalyst under pressure (100 psi) yielded epoxy‐terminated dendrimer in very high yield (95%). The epoxy‐terminated dendrimer was reacted with aminopropylalkoxysilanes to yield the next‐generation dendrimer bearing dialkoxy and trialkoxy silane groups. The dendrimers were characterized by the usual physico‐chemical techniques, i.e. elemental analysis, FT‐IR, 1H, 13C and 29Si NMR. Thermal studies (Thermogravimetric analysis and Thermomechanical analysis) of the alkoxy terminated dendrimers and its cured products were also carried out. Copyright © 2010 John Wiley & Sons, Ltd.

Synthesis and cytotoxic activity of new 2‐[(3‐aminopropyl)dimethylsilyl]‐5‐triethylsilylfurans

AbstractHighly cytotoxic 3‐aminopropyl derivatives of 5‐triethylsilyl‐2‐dimethylsilylfuran (LC501–3 µg ml−1) have been prepared by hydrosilylation of heterocyclic N‐allylamines with corresponding hydrosilane in the presence of Speier's catalyst. The influence of the amine structure on the cytotoxicity has been investigated. Copyright © 2009 John Wiley & Sons, Ltd.

Synthesis and characterization of some novel silicon esters and their application as lubricant base stock solution

AbstractA series of functional organosilanes and their esters were synthesized by the hydrosilylation reaction of SiH group‐bearing organosilicon derivatives with maleic anhydride using Speier's catalyst and their esterification with long‐chain alcohols in the presence of stannous oxide. These products have been characterized using elemental analysis, FT‐IR, 1H, 13C and 29Si NMR. Viscosity, density, pour point, flash point and tribological properties of these compounds have also been evaluated. These esters have a pour point of <−60 °C, a flash point of ∼200 °C (closed‐cup) and excellent load carrying capacity. Copyright © 2009 John Wiley & Sons, Ltd.

Surface-hydrophilic and protein-resistant silicone elastomers prepared by hydrosilylation of vinyl poly(ethylene glycol) on hydrosilanes-poly(dimethylsiloxane) surfaces

Poly(ethylene glycol) (PEG) was grafted on the hydrophobic poly(dimethylsiloxane) (PDMS) surface as a hydrophilic outmost monolayer for potential applications such as biomaterials, microfluidics, and anti-fouling coatings. A two component sylgard 184 PDMS (part A of poly(hydrogen methyl siloxane) (PMHS) and part B of poly(methyl vinyl siloxane) (PMVS)) was vulcanized in an off-ratio of, A/B > 1/10, where excess Si–H species exist in the elastomer. An allyl PEG took the hydrosilylation reaction with the surface Si–H groups, catalyzed by the Speier's or Karstedt's catalyst, and resulted a hydrophilic and anti-fouling surface. Atomic Force Microscopy (AFM) observations revealed a well uniform surface with a surface height variation at angstrom scale. Bovine Serum (BS), Bovine Serum Albumin (BSA), Lysozyme (Lys), and Rb IgG/FITC were used to evaluate the protein adsorption on PEG-coated PDMS surface by means of the well-established ATR-FTIR and fluorescence scanner. Results indicated that the PEG monolayer was efficient in reducing the adsorption of proteins.

Hydrosilylation of cyclohexene and allyl chloride with trichloro-, dichloro(methyl)-, and chlorodimethylsilanes in the presence of Pt(0) complexes

Hydrosilylation of cyclohexene and allyl chloride in the presence of Pt(0) complexes with tetramethyldivinyldisiloxane (Karstedt catalyst) and hexavinyldisiloxane was studied. It was shown that these catalysts are much more active in the hydrosilylation of cyclohexene with trichloro-, dichloro(methyl)-, and chlorodimethylsilane than the Pt(II)-containing Speier catalyst. In the hydrosilylation of allyl chloride in the presence of Pt(0) complexes, the ratio of the fraction of addition products to the fraction of reduction products increases from 5.7 (Speier catalyst) to 10–16. Quantum-chemical calculations showed that Pt(0) complexes are more active than Pt(II) complexes on the stage of formation of platinum silicon hydride complexes.

Preparation of luminescent sol–gel films from europium and terbium 3-(3′-triethoxysilylpropyl)pentane-2,4-dione complexes

Transparent luminescent sol–gel films have been prepared from the complexes of EuIII and TbIII with the new ligand 3-(3′-triethoxysilylpropyl) pentane-2,4-dione synthesised by the reaction of 3-allylpentane-2,4-dione with triethoxysilane in the presence of Speier catalyst.

Synthesis of carbohydrate‐segmented polydimethylsiloxanes by hydrosilylation

AbstractCarbohydrate‐modified polysiloxanes have been presented several times within the last decade. In this work, a new route to carbohydrate‐segmented polysiloxanes is presented. A series of allyl‐group‐containing bifunctional carbohydrate derivatives was synthesized and reacted with hydrodimethylsilyl‐terminated polysiloxane in hydrosilylation reactions with Speier's catalyst. The carbohydrate monomers and the resulting materials were fully characterized with 1H and 13C NMR spectroscopy. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3814–3822, 2005

Synthesis and Characterisation of Terminal Carbohydrate Modified Poly(dimethylsiloxane)s

AbstractSummary: In the 1990's, carbohydrate modified silicones were developed as a novel class of hydrophilic modified silicones which are now ready for marketing and industrially available, mainly as ingredients of cosmetic formulations. This report focuses on the synthesis of α,ω‐carbohydrate modified linear poly(dimethylsiloxane)s by hydrosilylation reactions. Thus, a series of carbohydrate derivatives was synthesised and reacted with a hydrodimethylsilyl‐terminated poly(dimethylsiloxane) applying Speier's catalyst. The resulting oils were characterised by MALDI TOF MS and NMR spectroscopy. Deprotection gave a series of novel amphiphilic modified silicones, which were more viscous than their protected analogues, due to hydrogen bonding.General structure of the amphiphilic carbohydrate modified poly(dimethylsiloxane)s.magnified imageGeneral structure of the amphiphilic carbohydrate modified poly(dimethylsiloxane)s.

Hydrosilylation of 2‐(2‐Propynyl)‐2,3‐dihydro‐1,2‐benzothiazol‐3‐one 1,1‐Dioxide with 1‐Alkynyl(dimethyl)‐ and Bis(1‐alkynyl)methylsilanes.

AbstractFor Abstract see ChemInform Abstract in Full Text.