Merrifield Resin Research Articles

Aminoalkylated Merrifield Resins Reticulated by Tris-(2-chloroethyl) Phosphate for Cadmium, Copper, and Iron (II) Extraction

We aimed to synthesize novel substituted polymers bearing functional groups to chelate heavy metals during depollution applications. Three polyamine functionalized Merrifield resins were prepared via ethylenediamine (EDA), diethylenetriamine (DETA), and triethylenetetramine (TETA) modifications named, respectively, MR-EDA, MR-DETA, and MR-TETA. The aminoalkylated polymers were subsequently reticulated by tris-(2-chloroethyl) phosphate (TCEP) to obtain new polymeric resins called, respectively, MR-EDA-TCEP, MR-DETA-TCEP, and MR-TETA-TCEP. The obtained resins were characterized via attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), elemental analysis (EA), and thermogravimetric (TGA), thermodynamic (DTA), and differential thermogravimetric (DTG) analysis. The synthesized resins were then assayed to evaluate their efficiency to extract metallic ions such as Cd2+, Cu2+, and Fe2+from aqueous solutions.

A Merrifield resin supported Pd–NHC complex with a spacer(Pd–NHC@SP–PS) for the Sonogashira coupling reaction under copper- and solvent-free conditions

Synthetic applications of a polymer supported air-stable palladium NHC complex with a spacer (catalyst6, Pd–NHC@SP–PS) and without a spacer (catalyst7, Pd–NHC@PS) have been studied for the Sonogashira cross-coupling reaction.

A new 2-oxy-N,N-dioctylacetamide grafted resin for the separation of trivalent actinides from nitric acid medium

Abstract A novel 2-oxy-N,N-dioctylacetamide anchored on Merrifield resin was synthesized and characterized by elemental analysis, TG-DTA and IR spectroscopy, for the first time. The extraction behavior of Am(III) and Eu(III) from nitric acid medium in the dioctylacetamide anchored resin (R-DOA) was studied as a function of various parameters such as duration of equilibration, concentration of nitric acid and sodium nitrate etc. The distribution coefficient (K d) of Am(III) and Eu(III) in R-DOA increased with increase in concentration of nitric acid. The K d values reached a maximum at 3–4 M nitric acid concentration in both cases, followed by decrease in K d values. Rapid extraction of Am(III) and Eu(III) from nitric acid medium was observed in the initial stages of equilibration followed by the establishment of equilibrium occurred within 60 min. The extraction data was fitted in to the first order rate equation. The recovery of Am(III) and Eu(III) from the loaded organic phase was studied using dilute nitric acid. The results revealed that 2-oxyacetamide functionalized resin is the promising candidate for the separation of trivalent actinides and lanthanides from nitric acid medium.

Photoluminescent hybrid materials of lanthanide (Eu3+, Sm3+) polyoxometalates and polymer resin through ionic liquid linker

We achieve luminescent soft hybrid materials with lanthanide polyoxometalates and polymer resin (Merrifield resin (MR) or Wang resin (WR)) through ionic liquid compound (3-(2-(2-mercaptoacetoxy)ethyl)-1-methyl-1H-imidazol-3-ium bromide (SHIL)) as chemical linker, which are designated as LnW10-SHIL-MR(WR) (Ln = Eu, Sm). The photoluminescent properties of these hybrids are characterized, and it is found that they present excitation both in the ultraviolet and visible regions. Under the excitation at the visible region, the yellow-orange emission is obtained for the LnW10 unit. Subsequently, the white luminescence for the excitation at the visible region can be observed. This provides the useful data to prepare the white luminescent soft hybrids of polymer and lanthanide polyoxometalates through an ionic liquid linker.

Synthesis of glycerol carbonate from the transesterification of dimethyl carbonate with glycerol using DABCO and DABCO-anchored Merrifield resin

Both DABCO (1,4-diazabicyclo[2.2.2]octane) and Merrifield resin-anchored DABCO ([p-DABCO]Cl), prepared from the reaction of DABCO and Merrifield resin, were found to exhibit high activities for the transesterification of dimethyl carbonate (DMC) with glycerol to produce glycerol carbonate (GLC). FT-IR and NMR spectroscopic results suggest that such a high transesterification activity of DABCO could be attributed to its superior ability to activate glycerol via a strong hydrogen bond formation between a hydroxyl group of glycerol and an amino group of DABCO. Meanwhile, the activation of glycerol by [p-DABCO]Cl proceeds mainly through the hydrogen bond interaction between a hydroxyl group or groups of glycerol and Cl− of [p-DABCO]Cl. The catalytic activity of [p-DABCO]Cl was maintained up to 5 reuses, demonstrating that [p-DABCO]Cl could be used as a recyclable heterogeneous catalyst.

Parallel synthesis of 2,4,5-trisubstituted thiophene-3-carbonitrile derivatives on traceless solid support

A parallel solid-phase synthesis of 2,4,5-trisubstituted thiophene-3-carbonitrile derivatives was developed. The polymer-supported synthetic route progressed using the sulfide linker via a traceless strategy. The initial synthesis utilized the Thorpe–Ziegler type cyclization of α-haloketone and polymer-supported 2,2-dicyanoethene-1,1-bis(thiolate), which was derived from the Merrifield resin. The resulting thiophene resin was introduced to one substitution by N-arylation. After oxidation of sulfides to sulfones in the thiophene resins for subsequent cleavage, nucleophilic desulfonative substitution with amines and thiols afforded the desired thiophene-3-carbonitrile derivatives in good overall yields.

Sorption of Eu(III) on Merrifield resin modified with thiacalix[4]arenes

We have studied the sorption of Eu(III) ions on Merrifield resin (chloromethylated polystyrene) impregnated and covalently modified with tetrahydroxythiacalix[4]arenes that contain hydrogen atoms, tertbutyl, and dialkoxyphosphonylmethyl moieties on the macrocyclic upper rim. The resulting materials have a sorption capacity of up to 70 mg/g and allow one to extract up to 99% of Eu(III) from aqueous solutions with medium mineral content at pH 5.5–6.

Photoactive hybrid materials of lanthanide (Eu3+, Tb3+, Sm3+) beta-diketonates and polymer resin through ionic liquid bridge.

A special multifunctional ionic liquid compound (1-methyl-3-(2-(thiocarboxyoxy)-ethyl)-2H-imidazole-1,3-diium bromide (SHIL)) is used as the chemical bridge to link lanthanide beta-diketonates and polymer resin, which are designated as Ln(L)4-SHIL-WR/MR (Ln = Eu, Tb, Sm; L = thenoyltrifluoroacetonate (TTA), acetylacetonate (AA), dibenzoylmethane (DBM); WR = Wang resin, MR = Merrifield resin). Among SHIL and polymer resin are assembled to form covalently bonded system through condensation reaction. Then tetrakis lanthanide beta-diketonates are linked to SHIL through ion-exchange reaction. Physical characterization and especially the photoluminescent performance of the multicomponent hybrids are studied. The hybrid materials possess good stability and excellent luminescent property. The results provide useful path to obtain luminescent hybrids for further practical application.

Pyrrolidine-fused chlorin photosensitizer immobilized on solid supports for the photoinactivation of Gram negative bacteria

The emergence of resistant microorganism to conventional therapeutics prompted us to search new and better antimicrobial treatment modalities. In this work was envisaged an economically viable and environmental friendly approach to allow successive recovery and removal of the photosensitizer agent after photodynamic treatment. The photodynamic inactivation of bioluminescent Escherichia coli in the presence of an immobilized cationic chlorin photosensitizer and its reusability are described. The chlorin photosensitizer (PS) was immobilized on two commercial materials: a 3-bromopropyl-functionalized silica and a Merrifield resin. The new photosensitising materials were characterized by UV–vis spectroscopy, SEM and EDX. Their singlet oxygen generation capacities were also assessed. Previous studies showed that there is a direct relationship between the photoinactivation efficiency and the number of positive charges on such PS molecules. Therefore the number of positive charges on the new prepared materials was further increased by treatment of the PS-immobilized materials with 1-methylimidazole and pyridine. The efficiency of photoinactivation against bioluminescent E. coli was evaluated in the presence of the non-immobilized chlorin (20 μM) as well as in the presence of the new prepared materials positively charged or non-charged on the surface (20–200 μM) with white light at an irradiance of 4.0 mW cm−2. Overall, this study shows that the materials resulting from the immobilization of the chlorin on the silica surface and on the Merrifield resin, followed by further treatment with pyridine, have high potential as PS for the inactivation of Gram negative bacteria (3.0 log reductions) and are able to maintain its antimicrobial efficiency after at least 3 repeated cycles of photoinactivation. Their reusability, without loss of effectiveness, confirms a potential inexpensive and friendly application in clinic and environmental areas.

An easy purification of glycoluril clips by affinity chromatography

A convenient method for separation and purification of glycoluril clips was developed on the basis of affinity chromatography using a resorcinol-functionalized Merrifield resin. The modified resin was readily prepared via immobilization of phlroglucinol on Merrifield resin. It was used for successful isolation of the desired clip products from their corresponding reaction mixtures. Also, the resin could be repeatedly recycled and reused without any noticeable decrease in its effectiveness.

Catalytic Performance of Polystyrene‐Bound ChibaG Derivatives as Guanidine Organobases in Asymmetric Michael Additions

AbstractThe guanidine organocatalyst, ChibaG, was bound via an ether linkage to the phenyl group of the 2‐imino substituent to Merrifield resin. Polystyrene‐bound ChibaG acted as an effective catalyst in the Michael reaction of tert‐butyl N‐(diphenylmethylidene)glycinate with methyl vinyl ketone, and could be recovered and reused many times.

ChemInform Abstract: Merrifield Resin Supported Peroxomolybdenum(VI) Compounds: Recoverable Heterogeneous Catalysts for the Efficient, Selective and Mild Oxidation of Organic Sulfides with H2O2.

AbstractAll reactions can be conducted at room temperature as well, merely expanding the reaction time.

ChemInform Abstract: PCP‐Pincer Palladium Nanoparticles Supported on Modified Merrifield Resin: A Novel and Efficient Heterogeneous Catalyst for Carbon—Carbon Cross‐Coupling Reactions.

AbstractThe catalyst can be re‐used up to 10 times without significant loss in activity.

Development of a new linker for the solid-phase synthesis of N-hydroxylated and N-methylated secondary amines

Merrifield resin was modified by the introduction of an ortho-nitrophenylethanal group that served as a linker moiety to attach amines to the resin by reductive amination. Resin-bound tertiary amines were shown to be readily transferred into the respective liberated N-hydroxylated or N-methylated derivatives by either an oxidation/Cope elimination or a permethylation/Hofmann elimination protocol. With these two divergent liberation/derivatization options, the new resin offers new flexibility in the solid phase synthesis of N-modified secondary amines, for instance in spider toxin synthesis.

Using low-frequency IR spectra for the unambiguous identification of metal ion–ligand coordination sites in purpose-built complexes

One of the aims of our long-term research is the identification of metal ion–ligand coordination sites in bioinspired metal ion–C- or N-protected amino acid (histidine, tyrosine, cysteine or cystine) complexes immobilised on the surface of chloropropylated silica gel or Merrifield resin. In an attempt to reach this goal, structurally related, but much simpler complexes have been prepared and their metal ion–ligand vibrations were determined from their low-frequency IR spectra. The central ions were Mn(II), Co(II), Ni(II) or Cu(II) and the ligands (imidazole, isopropylamine, monosodium malonate) were chosen to possess only one-type of potential donor group. The low-frequency IR spectra were taken of the complexes for each ion–ligand combination and the typical metal ion-functional group vibration bands were selected and identified. The usefulness of the obtained assignments is demonstrated on exemplary immobilised metal ion-protected amino acid complexes.

A new synthetic approach to oxidation organocatalysts supported on Merrifield resin using plasma-enhanced chemical vapor deposition

Described here is the first application of plasma-enhanced chemical vapor deposition (PE-CVD) to the synthesis of catalytically active materials, prepared by covering Merrifield resin beads with an oxygen-containing fluorocarbon thin film deposited in a hexafluoropropene-O2 plasma. Such modified resins catalyze both the selective epoxidation of trans-β-methylstyrene and its double oxidative cleavage to benzaldeyde in organic–water biphasic media at room temperature, using potassium monoperoxysulfate (KHSO5) as the terminal oxidant. Interestingly, the epoxide/benzaldehyde product ratio strictly depends on the conditions adopted for catalyst generation. This, coupled with evidence for the presence of carbonyl groups on the surface of treated resins, point to dioxirane and singlet oxygen (1O2)-mediated oxidations; 1O2 being produced in the decomposition of KHSO5. Compared to traditional synthetic procedures to obtain similar catalytic active materials, the application of PE-CVD is eco-sustainable and less expensive. Also, the activity of catalysts can be fully restored upon iterative re-treatment of the exhausted resin.

Immobilization of [Pt2(μ-S)2(PPh3)4] on Polymeric Supports by Sulfide Alkylation and Phosphine Exchange Reactions

The immobilization of the dinuclear platinum(II) sulfido complex [Pt2(μ-S)2 (PPh3)4] on solid supports has been investigated. Reaction with haloalkyl functionalized polymers [Merrifield's resin (chloromethylated polystyrene), chloropropyl silica, chloropropyl controlled pore glass, and bromopropyl polysiloxane] gives complexes immobilized through alkylation of one of the sulfide ligands, forming a μ-thiolate ligand acting as an anchor to the polymer support, akin to well-established reactions of [Pt2(μ-S)2(PPh3)4] with molecular alkylating agents. The model complex [Pt2(μ-S)(μ-SCH2SiMe3)(PPh3)4]PF6 was prepared as the first molecular silicon-containing derivative of [Pt2(μ-S)2(PPh3)4] and was fully characterized by NMR spectroscopy, electrospray ionization-mass spectrometry, and single-crystal X-ray diffraction. Immobilization of [Pt2(μ-S)2(PPh3)4] by phosphine exchange reactions was also achieved using commercial polystyrene-grafted triphenylphosphine or a new immobilized phosphine [derived by sequential functionalization of Merrifield's resin with a polyether amine and then Ph2PCH2OH].

Polymer-supported ionic liquids: Synthesis, characterization and application in fuel desulfurization

Ionic liquids (ILs) were considered to be immobilized on solid supports to overcome the problems of the pure ILs in fuel desulfurization. Take Merrifield resin as solid support, four polymer-supported imidazole ionic liquids (PSILs) with different lengths of alkyl chain linkers were prepared by covalent binding and the structures were characterized by Fourier transform infrared (FTIR), elemental analysis, 13C solid state magic-angle-spinning nuclear magnetic resonance (MAS NMR) spectroscopy, scanning electron microscope (SEM) and energy dispersive spectrometer (EDS). The results suggested the series PSILs had been obtained. Then, the PSILs were investigated to remove thiophene (TS) or dibenzothiophene (DBT) from model gasoline (cyclohexane/TS or DBT) under certain conditions: (1) PSILs showed better sulfur removal ability than Merrifield resin, PS[unmim][BF4] showed the best percent sulfur removal which could up to ⩾30% due to the longest alkyl chain linker and the smallest particles. (2) The sulfur removal selectivity of DBT was better than TS for its higher density aromatic π-electrons. The Sips adsorption isotherms model fitted the adsorption experimental data of PS[unmim][BF4] for TS and DBT at 303.15K best. Finally, the adsorption mechanism was discussed.

Synthesis of bifunctional cyclic carbonates from CO2 catalysed by choline-based systems

Abstract Easily prepared choline iodide is an active catalyst for the synthesis of cyclic carbonates through the coupling reaction of CO 2 and epoxides using low pressure (1 MPa), moderate temperature (85 oC) and green solvents (ethanol and propan-2-ol). The effects of reaction temperature, pressure, reaction time and amount of catalyst used were also investigated. The results showed moderate to high yields and excellent selectivities of cyclic carbonates with vinyl or acrylate groups under mild reaction conditions. The heterogenization of choline over a Merrifield resin gives access to a supported catalyst with good recyclability and reactivity that can be extended to a variety of terminal epoxide substrates.

Rasta Resin-TBD as a Reusable Catalyst for Transesterification Reactions

Rasta resin-TBD has been synthesized and used to catalyze a wide range of transesterification reactions, including biodiesel synthesis and ring-opening polymerizations. It was found to be a more efficient heterogeneous catalyst than a related polystyrene-based analogue based on the Merrifield resin architecture involving divinylbenzene cross-linking. In the reactions studied rasta resin-TBD was separated from the desired products simply by filtration, and it could be regenerated and reused numerous times without significant loss of catalytic activity.