"Thiol-ene" click chemistry: a facile and versatile route for the functionalization of porous polymer monoliths

The preparation of porous polymer monoliths with dodecyl and zwitterionic functionalities via the "thiol-ene" click chemistry of thiol-containing monoliths with both hydrophobic and polar methacrylate "ene" monomers has been demonstrated. Selected separations confirmed the excellent potential of these monoliths in chromatography.     

Topological polymer chemistry by programmed self-assembly and effective linking chemistry

Ongoing challenges in topological polymer chemistry are reviewed. In particular, we focus on recent developments in an “electrostatic self-assembly and covalent fixation (ESA–CF)” process in conjunction with effective linking/cleaving chemistry including a metathesis process and an alkyne–azide click reaction. A variety of novel cyclic polymers having specific functional groups and unprecedented multicyclic macromolecular topologies have been realized by combining intriguing synthetic protocols.     

Exohedral functionalization of fullerenes and supramolecular chemistry

We have investigated the exohedral functionalization of [60]fullerene, especially bisaddition; we have revealed the regioselectivity of bisaddition and the properties of obtained bisadducts. The bisaddition without any restriction generally shows low regioselectivity. The electronic and photophysical properties of bisadducts mainly depend on the addition patterns and are almost independent of the nature of addends. We have also attained the regioselective synthesis of bisadducts by controlling the distance and orientation between two reactive species with suitable covalent templates and their application into some functional materials. The synthesis of fullerene‐containing interlocked molecules, such as catenanes and rotaxanes, was accomplished by using a noncovalent interaction, mainly a donor‐acceptor interaction, in addition to the covalent functionalization. The bistable rotaxanes, which can serve as a molecular shuttle or switch, were also successfully prepared. DOI 10.1002/tcr.201000036     

Facile functionalization of isotactic polypropylene by azide and alkyne groups for click chemistry application

This paper presents two facile methods to achieve functionalization of isotactic polypropylene (i‐PP) by azide and alkyne groups. One method comprises metallocene‐catalyzed isospecific propylene polymerization with dialkylzinc as chain transfer agent to produce iodo‐terminated i‐PP, which can be transformed to azide‐terminated i‐PP. The other utilizes hydroxyl‐grafted i‐PP as a raw material to react with bis (trichloromethyl)carbonate and propargyl amine, generating grafted alkyne groups. Both approaches are effective, controllable and safe. The azide‐terminated and alkyne‐grafted i‐PP are readily applicable to click chemistry for construction of new i‐PP architecture, e.g. long‐chain branched i‐PP. Copyright © 2011 John Wiley & Sons, Ltd.     

Photochemical functionalization of polymer surfaces for microfabricated devices

Herein we report the topochemical modification of polymer surfaces with perfluorinated aromatic azides. The aryl azides, which have quaternary amine or aldehyde functional groups, were linked to the surface of the polymer by UV irradiation. The polymer substrates used in this study were cyclic olefin copolymer and poly(methyl methacrylate). These substrates were characterized before and after modification using reflection-absorption infrared spectroscopy, sessile water contact angle measurements, and X-ray photoelectron spectroscopy. Analysis of the surface confirmed the presence of aromatic groups with aldehyde or quaternary amine functionality. Enzyme immobilization and patterning onto polymer surfaces were studied using confocal microscopy. Enzymatic digests of protein were carried out on modified probes manufactured from thermoplastic substrates, and the resulting peptide analysis was completed using matrix-assisted laser desorption/ionization mass spectrometry. The use of functionalized perfluorinated aromatic azides allows the surface chemistry of thermoplastics to be tailored for specific lab-on-a-chip applications.     

Multivalent polymer vesicles via surface functionalization

A new method was developed for the conjugation of multivalent dendritic groups to polymer vesicle surfaces.     

Topological polymer chemistry by dynamic selection from electrostatic polymer self-assembly

A collection of recent developments in topological polymer chemistry is presented. First, topological isomerism occurring on randomly coiled, flexible polymer molecules having cyclic and linear structures is discussed. Second, an electrostatic self-assembly and covalent fixation strategy has been developed for the synthesis of polymeric topological isomers. These isomers have double cyclic, manacle-, and theta-shaped constructions, and are prepared by using either linear or star telechelic polymer precursors having moderately strained cyclic ammonium salt groups, which carry multifunctional carboxylate counteranions. A technique of reversed-phase chromatography (RPC) is demonstrated as an effective means to separate polymers with different topologies, especially polymeric topological isomers. A further extension of topological polymer chemistry has been observed by dynamic selection from electrostatic polymer self-assembly to enable the effective formation of tadpole-shaped, cyclic-linear hybrid topologies.     

Stereocontrolled functionalization of cyclohexene using organomolybdenum chemistry

Cyclohexadiene-Mo(CO)₂Cp cations react stereospecifically with stabilised enolate nucleophiles to give π-allyl complexes which are converted to substituted allylic iodides on treatment with iodine.     

Supramolecular polymer chemistry

Supramolecular chemistry aims at constructing highly complex chemical systems and advanced materials by designing arrays of components held together by intermolecular forces. The implementation of molecular recognition and information offers means for controlling the evolution and the architecture of supramolecular entities and of organised phases as they spontaneously build up from their components through self‐organisation.     

Ortho-spirocarbonates and ortho-spirothiocarbonates: synthesis, functionalization and coupling

This paper describes a new efficient synthesis of 2,2′-spirobi-(1,3-benzoxathiole) (1), 2,2′-spirobi-(1,3-benzodithiole) (2) and 2,2′-spirobi-(1,3-benzodioxole) (3). Compound 3 has been functionalized by means of metallation reaction followed by electrophilic quenching to give carboxylic acids, aldehydes and alcohols. Furthermore compound 3 was subjected to homo-coupling and its dimeric structure was determined by XRD analysis.     

Stereo- and regio-controlled functionalization of cycloheptene using organomolybdenum chemistry

Cycloheptene is readily converted to the cationic cycloheptadiene-Mo(C0)₂Cp complex, which reacts with a range of nucleophiles; hydride abstraction from the product π-allyl-Mo(C0)₂Cp complexes give substituted cycloheptadiene complexes which react with a second nucleophile stereospecifically, and decomplexation of the π-allyl complexes gives substituted cycloheptene derivatives with defined relative stereochemistry.     

Uniform polymer in synthetic polymer chemistry

The preparation of uniform polymers and their use in fundamental polymer chemistry are reviewed. A typical method of preparation is a combination of living polymerization and supercritical fluid chromatography separation. Synthetic uniform polymers allow us to solve ambiguous problems in polymer chemistry due to molecular weight distribution and are of significant importance for studies on structure–property relationships. A close inspection of an isotactic uniform chloral oligomer with a symmetrical chemical structure reveals that oligomers are the first examples of stable atropisomers of aldehyde oligomers and that their chiroptical properties are due only to their helical geometries. A molecular-level understanding of the mechanism and stoichiometry of the association process of polymer molecules is possible only with uniform polymers, and stereocomplex formation between isotactic and syndiotactic poly(methyl methacrylate)s in acetone has vigorously been studied by size exclusion chromatography (SEC) and NMR. End-functionalized uniform polymers have enabled us to prepare uniform polymer architectures, such as block, graft, comb, and star polymers. A uniform stereoblock poly(methyl methacrylate) with an isotactic (methyl methacrylate)₄₆-syndiotactic (methyl methacrylate)₄₆ structure shows a single SEC peak in chloroform but three peaks in acetone, which are ascribable to intermolecularly and intramolecularly associated complexes and nonassociated molecules. A three-arm star polymer with one isotactic chain and two syndiotactic chains shows a peculiar SEC behavior in acetone due to a braid type of intramolecular stereocomplex formation. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 416–431, 2004     

Bio-click chemistry: enzymatic functionalization of PEGylated capsules for targeting applications

All sorted: The enzyme Sortase?A was used to catalyze functionalization of PEGylated capsules with an activation-specific anti-platelet single-chain antibody (scFv). This enzymatic method allows fast, covalent, and site-directed functionalization of delivery vehicles under mild conditions. Activation-specific anti-platelet scFv-coated PEGylated capsules exhibited a high level of selective binding to thrombi, thus suggesting their potential for thrombosis therapy.     

Selective functionalization of 3-D polymer microstructures

We demonstrate the selective functionalization of 3-D polymer microstructures that were created using multiphoton absorption polymerization. By fabricating different portions of the structures with acrylic and methacrylic polymers, we are able to take advantage of the differential reactivities of these materials to perform functionalization chemistry on a single polymeric component. We demonstrate the selective deposition of metal to create structures, such as a functional microinductor. Our strategy is quite general and can be extended readily to the deposition of materials, such as metal oxides and biomolecules.     

Liquid crystal functionalization of electrospun polymer fibers

A recently introduced new branch of applied polymer science is the production of highly functional and responsive fiber mats by means of electrospinning polymers that include liquid crystals. The liquid crystal, which provides the responsiveness, is most often contained inside fibers of core‐sheath geometry, produced via coaxial electrospinning, but it may also be inherent to the polymer itself, for example, in case of liquid crystal elastomers. The first experiments served as proof of concept and to elucidate the basic behavior of the liquid crystal in the fibers, and the field is now ripe for more applied research targeting novel devices, in particular in the realm of wearable technology. In this perspective, we provide a bird's eye view of the current state of the art of liquid crystal electrospinning, as well as of some relevant recent developments in the general electrospinning and liquid crystal research areas, allowing us to sketch a picture of where this young research field and its applications may be heading in the next few years. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part B Polym. Phys. 2013, 51, 855–867     

Dendritic surface functionalization of biodegradable polymer assemblies

The functionalization of nanomaterials with dendritic surface moieties was recently demonstrated to be an effective means of displaying biological ligands and potentially modulating the biological properties of these materials. With the aim of extending this surface functionalization approach to biodegradable polymer assemblies, poly(ethylene oxide)‐polycaprolactone (PEO‐PCL) block copolymers with terminal azide or methoxy groups were prepared and were assembled to form micelles or vesicles with varying loadings of surface azides. Dendrons bearing peripheral amines, guanidines, or hydroxyls were prepared and conjugated to the assemblies, and the conjugation yields were measured and compared as a function of azide loading and assembly type (micelle versus vesicle). A small molecule rhodamine derivative was also conjugated, allowing the effect of sterics to be studied. The effects of the surface functionalization on the aggregation state of the assemblies were studied by light scattering and transmission electron microscopy. Overall, the results revealed interesting differences between the two systems with respect to both the reaction yields and the stabilities. Furthermore, micelles functionalized with dendrons bearing peripheral guanidines were found to exhibit enhanced cell uptake relative to control micelles, demonstrating that this approach can be used to modulate the biological properties of the materials. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Sequential functionalization of porous coordination polymer crystals

Crystal extractor: Heterostructured porous coordination polymer crystals fabricated using epitaxial growth have two contradictory porous functions, namely size selectivity and high storage. The crystals not only extract linear petroleum molecules from a mixture with its branched isomer, even at very low concentrations of linear isomer (1?wt?%), but also shows improved accumulation of the molecules in its pores.     

Noncovalent functionalization and solubilization of carbon nanotubes by using a conjugated Zn-porphyrin polymer

A highly soluble, conjugated Zn-porphyrin polymer was synthesized and found to strongly interact with the surface of single-walled carbon nanotubes, producing a soluble polymer-nanotube complex. Successful complexation required the addition of trifluoroacetic acid to the solvent (THF). It was found that the complex remained soluble after excess free polymer was removed from solution, and could be centrifuged at high speed with no observable sedimentation. Furthermore, the polymer-nanotube assembly resulted in enhanced planarization and conjugation within the porphyrin polymer, which was manifested in a 127 nm bathochromic shift of the Q-band absorption. Control experiments with the Zn-porphyrin monomer indicated that homogeneous solutions could be prepared by means of sonication, but the monomer-nanotube interactions were significantly weaker, leading to nanotube precipitation within minutes. Atomic force microscopy (AFM) studies indicated that the polymer enables exfoliation of nanotube bundles and is able to "stitch" multiple nanotubes together into a series of long, interconnected strands.     

From molecular chemistry to hybrid nanomaterials. Design and functionalization

This tutorial review reports upon the organisation and functionalization of two families of hybrid organic-inorganic materials. We attempted to show in both cases the best ways permitting the organisation of materials in terms of properties at the nanometric scale. The first family concerns mesoporous hybrid organic-inorganic materials prepared in the presence of a structure-directing agent. We describe the functionalization of the channel pores of ordered mesoporous silica, that of the silica framework, as well as the functionalization of both of them simultaneously. This family is currently one of the best supports for exploring polyfunctional materials, which can provide a route to interactive materials. The second family concerns lamellar hybrid organic-inorganic materials which is a new class of nanostructured materials. These materials were first obtained by self-assembly, as a result of van der Waals interactions of bridged organosilica precursors containing long alkylene chains during the sol-gel process, without any structure directing agent. This methodology has been extended to functional materials. It is also shown that such materials can be obtained from monosilylated precursors.