Laser Writing of Block-Copolymer Images into Mesopores Using SBDC-Initiated Visible-Light-Induced Polymerization

For miniaturization, as well as for improving artificial nanopore performance, precise local polymer functionalization and the combination of different functionalities are required. Imagining data driven nanopore design automated nanopore functionalization would be beneficial. Using direct laser writing as one option of automated nanopore polymer functionalization visible light induced polymerizations are beneficial. Here, we demonstrate the functionalization of mesoporous silicafilms with two different polymers using automated laser writing. For this we developed a visible light (400–700 nm and 405 nm) N,N(diethylamino)dithiocarbamoylbenzyl(trimethoxy)silane (SBDC) inifierter initiated polymerization. While transferring this visible light induced polymerization using SBDC to a commercially available microscope, direct, automated laser writing, as well as polymer re-initiation was demonstrated. Thereby, polymer spots of 37 and 40 μm in diameter were achieved using 1–5 seconds for each irradiated spot.     

Modular Approach to Degradable Acetal Polymers Using Cascade Enyne Metathesis Polymerization

A modular synthetic approach to degradable metathesis polymers is presented using acetal‐containing enyne monomers. The monomers are prepared in a short and divergent synthetic sequence that features two points of modification to tune polymerization behavior and introduce molecular cargo. Steric and stereochemical elements are critical in the monomer design in order to provide rapid and living polymerizations capable of generating block polymers. The developed polyacetal materials readily undergo pH‐dependent degradation in aqueous mixtures, and the rate of hydrolysis can be tuned through post‐polymerization modification with triazolinedione click chemistry. This presents a new scaffold for responsive metathesis polymers that may find use in applications that requires controllable breakdown and release of small molecules.     

Living Alternating Ring-Opening Metathesis Copolymerization of 2,3-Dihydrofuran to Provide Completely Degradable Polymers

2,3-Dihydrofuran (DHF) has recently been gaining significant attention as a comonomer in metathesis polymerization, thanks to its ability to provide the resultant polymer backbones with stimuli-responsive degradability. In this report, we present living alternating copolymerization of DHF with less reactive endo-tricyclo[4.2.2.0^2,5]deca-3,9-dienes (TDs) and endo-oxonorbornenes (oxoNBs). By carefully controlling the reactivity of both the Ru initiators and the monomers, we have achieved outstanding A, B-alternation (up to 98 %) under near stoichiometric DHF loading conditions. Notably, we have also found that the use of a more sterically hindered Ru initiator helps to attain polymer backbones with higher DHF incorporation and superior A, B-alternation. While preserving the living characteristics of DHF copolymerization, as evidenced by controlled molecular weights (up to 73.9 kDa), narrow dispersities (down to 1.05), and block copolymer formation, our DHF copolymers could be broken down to a single repeat unit level under acidic conditions. ¹H NMR analysis of the model copolymer revealed that after 24 hours of degradation, up to 80 % of the initial polymer was transformed into a single small molecule product, and after purification, up to 66 % of the degradation product was retrieved. This study provides a versatile approach to improve the alternation and degradability of DHF copolymers.     

Sodium hydride-initiated polymerizations of vinyl monomers in aprotic solvents

Polymerizations of several vinyl monomers at 25°C in aprotic solvents (dimethyl sulfoxide, N,N-dimethylacetamide, and hexamethylphosphoric triamide) using sodium hydride dispersion as initiator yield low to intermediate molecular weight polymers. The molecular weight of the resulting polymer as well as the mode of initiation depends on the monomer and aprotic solvent used. Initiation of polymerization of monomers with available α hydrogens (methyl acrylate, acrylonitrile) involves monomer anion, while initiation of a monomer with no α hydrogen (methyl methacrylate) proceeds by a more complex mechanism. In contrast, initiation of styrene and α-methylstyrene proceeds by dimsyl anion addition to monomer in dimethylsulfoxide. Although the triad tacticities and number-average molecular weights of poly(methyl methacrylate) samples obtained from all three aprotic solvents are nearly the same, poly(methyl methacrylates) prepared in dimethyl sulfoxide and N,N-dimethylacetamide give polymers having polydispersities of ～3, while a very polydisperse polymer is obtained in hexamethylphosphoric triamide.     

Contact bactericides and fungicides on the basis of amino‐functionalized poly(norbornene)s

This study is aimed at investigating the microbiocidal potential of amino‐functionalized poly(norbornenes) in the solid state. A series of norbornene‐type monomers that carry secondary or tertiary amine functions as well as hexyl and dodecyl groups were prepared. Ring‐opening metathesis polymerization was used to prepare homopolymers of the amine bearing monomers and random copolymers of amine‐ and alkyl‐substituted monomers of high average molar mass. The resulting polymers were characterized by nuclear magnetic resonance, thermogravimetry, differential scanning calorimetry, infrared spectroscopy, and contact angle measurements, and their contact biocidal potential was evaluated according to the Japanese Industry standard Z2801. Tested microorganisms comprised Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Candida albicans, and Aspergillus niger. Microbiocidal activity of selected polymer films against E. coli, S. aureus, and A. niger was found, whereas against C. albicans and P. aeruginosa microbiostatic behavior was observed. Moreover, the most potent copolymer revealed no cytotoxicity rendering a biocidal polymer with potential applications in mammalian‐, and in particular, human‐related fields. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

Development of an Enyne Metathesis/Isomerization/Diels–Alder One‐Pot Reaction for the Synthesis of a Novel Near‐Infrared (NIR) Dye Core

N‐Alkyl‐N‐allyl‐2‐alkynylaniline derivatives undergo a tandem ring‐closing enyne metathesis/isomerization/Diels–Alder cycloaddition sequence in the presence of a second‐generation Grubbs catalyst and dienophiles. In practice, the acyclic enyne in the presence of the ruthenium alkylidene first undergoes ring‐closing metathesis to generate cyclic 4‐vinyl‐1,2‐dihydroquinolines; following diene isomerization and then the addition of a dienophile, these ring‐closing metathesis products are selectively converted into a 7‐methyl‐4H‐naphtho[3,2,1‐de]quinoline‐8,11‐dione core. Overall, the reaction sequence converts simple aniline derivatives into π‐conjugated small molecules, which have characteristic absorption in the near‐infrared region, in a single operation through three unique ruthenium‐catalyzed transformations.     

Combining α-amidoalkylation reactions of N-acyliminium ions with ring-closing metathesis: access to versatile novel isoindolones spirocyclic compounds

A novel approach to diversely spirocyclic isoindoles has been developed by using N-acyliminium/ring-closing metathesis strategy. Spirocyclization precursors, diolefinic, and enyne spiro-fused-isoindole derivatives have been obtained by a regioselective reduction of the spiro-imide compounds, followed by the allylation of the N-acyliminium intermediates (generated from the acetoxylactam compounds). Ruthenium catalyzed ring-closing metathesis of the above unsaturated derivatives provided novel spiroisoindoles.     

Synthesis of (+)-anatoxin-a using enyne metathesis

Synthesis of N-tosylanatoxin-a was achieved by metathesis of enyne in cis-substituents on a pyrrolidine derivative. Metathesis reactions of enyne having terminal alkyne using various ruthenium-carbene complexes did not give a good results. However, when the terminal alkyne was protected with a TMS group, the reaction proceeded smoothly using a second-generation ruthenium-carbene complex to give the desired cyclized compound in high yield. Oxymercuration followed by Dess-Martin oxidation afforded N-tosylanatoxin-a.     

Facile Synthesis of New Areneboronates as Terminal Ethyne Monomers

N-Methyliminodiethyl 2-ethynylbenzeneboronate was obtained by lithiation of phenylacetylene, addition of trimethyl borate, hydrolysis, and azeotropic condensation with N-methyl diethanolamine. 4-(Cyano-(4-ethynylphenylamino)methyl)benzeneboronate was prepared by a facile and efficient procedure from 4-ethynylaniline and N-methyliminodiethyl 4-formylbenzeneboronate, followed by scandium-catalyzed cyanation. These terminal ethyne monomers were shown to undergo β-insertion with a Schrock metathesis catalyst to yield boronic acid-functionalized oligomers.     

Application of an Enyne Metathesis/Diels–Alder Cycloaddition Sequence: A New Versatile Approach to the Syntheses of C‐Aryl Glycosides and Spiro‐C‐Aryl Glycosides

An efficient approach for the synthesis of a variety of C‐aryl and spiro‐C‐aryl glycosides is described. This diversity‐oriented strategy employed here relies on a sequential enyne metathesis to generate the 1,3‐diene moiety and Diels–Alder reaction with different dienophiles followed by aromatisation. Whereas cross‐enyne metathesis with ethylene gas is used to install the 1,3‐diene moiety at the anomeric centre for the synthesis of C‐aryl glycosides, an intramolecular enyne metathesis on the sugar enyne is performed to generate the 1,3‐diene moiety for the synthesis of spiro‐C‐aryl glycosides. Efforts to extend this strategy to the synthesis of the core structure of natural C‐aryl glycoside gilvocarcin are also described. A combination of both C‐aryl and spiro‐C‐aryl glycosides in the same moiety to combine the features thereof has also been accomplished. A tandem enyne metathesis/Diels–Alder reaction/aromatisation has also been attempted to directly access the C‐aryl glycosides in one pot albeit in low yield.     

Facile Synthesis of New Areneboronates as Terminal Ethyne Monomers

Summary. N-Methyliminodiethyl 2-ethynylbenzeneboronate was obtained by lithiation of phenylacetylene, addition of trimethyl borate, hydrolysis, and azeotropic condensation with N-methyl diethanolamine. 4-(Cyano-(4-ethynylphenylamino)methyl)benzeneboronate was prepared by a facile and efficient procedure from 4-ethynylaniline and N-methyliminodiethyl 4-formylbenzeneboronate, followed by scandium-catalyzed cyanation. These terminal ethyne monomers were shown to undergo β-insertion with a Schrock metathesis catalyst to yield boronic acid-functionalized oligomers.     

Synthesis and polymerizability of CN monomers

The synthesis and polymerizability of imine C?N monomers is surveyed. The investigated imines were either far more reactive than similarly substituted C?C or C?O monomers, or too stable to polymerize. Imines with electron‐attracting substituents on N favor polymerization by anionic mechanism, but led only to low molecular weight polymers. Imines with a donor substituent on N, such as N‐arylmethyleneimines, polymerized by cationic or anionic mechanism. 1‐ and 2‐Aza‐1,3‐butadienes were also rather unstable and polymerized to oligomers. The symmetrically substituted 2,3‐diaza‐1,3‐butadienes could be purified and polymerized successfully using anionic initiators, resulting in both 1,4‐ and 1,2‐structures in the polymer backbone, depending on the substituents. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Solid-state initiation of polymerization of N-vinylcarbazole by gases

Chlorine gas has been shown by previous investigators to initiate the polymerization of solid N-vinylcarbazole at room temperature, giving a maximum yield of 66% polymer after 18 hr. This initiation of polymerization of N-vinylcarbazole without the application of heat, by a gas, is the only solid-state initiation other than those that are radiation-induced known to us. This study was undertaken in order to determine both the scope and the mechanism of the room-temperature solid-state initiation of vinyl polymerization of N-vinylcarbazole by gases. The gases (HCl, Cl₂, and N₂O₄) were absorbed by solid N-vinylcarbazole, giving very rapid exothermic polymerization: HCl, 37% polymer yield, M?_n 2500; Cl₂, 50% polymer yield, M?_n 4703; N₂O₄, 91% polymer yield, M?_n 7073. The gases NOCl, BF₃, and HBr were not absorbed by N-vinylcarbazole and did not initiate polymerization. The N₂O₄-initiated polymerization, which gave a high yield of polymer, was complete within 5 min. after introduction of gas. This polymerization method and the resulting polymer compared favorably with conventional peroxide-initiated melt polymerization and the polymer obtained thereform. The mechanism of gas-initiated polymerization, which was studied with introduction of inhibitors, appears to be classically cationic in nature.     

Selective extraction of clonazepam from human plasma and urine samples by molecularly imprinted polymeric beads

A molecularly imprinted polymer (MIP) based on free‐radical polymerization was prepared with 1‐(N,N‐biscarboxymethyl)amino‐3‐allylglycerol and N,N‐dimethylacrylamide as functional monomers, N,N‐methylene diacrylamide as the cross‐linker, copper ion‐clonazepam as the template and 2,2‐azobis(2‐methylbutyronitrile) as the initiator. The imprinted polymer was characterized by Fourier transform infrared spectroscopy, elemental analysis, thermogravimetric analysis, and SEM. The MIP of agglomerated microparticles with multipores was used for SPE. The imprinted polymer sorbent was selective for clonazepam. The optimum pH and sorption capacity were 5 and 0.18 mg/g at 20°C, respectively. The profile of the drug uptake by the sorbent reflects good accessibility of the active sites in the imprinted polymer sorbent. The MIP‐SPE was the most feasible technique for the extraction of clonazepam with a high recovery from human plasma and urine samples.     

Preparation and characterization of a novel molecularly imprinted polymer for the separation of glycyrrhizic acid

Molecularly imprinted polymers of glycyrrhizic acid were prepared by solution polymerization using glycyrrhizic acid as the template molecule, N‐vinypyrrolidone as functional monomer, N ,N‐methylene bisacrylamide as cross‐linker and ascorbic acid and hydrogen peroxide as initiators. Focused on the adsorption capacity and separation degree of the polymer to glycyrrhizic acid, the effects of the monomers, crosslinker and initiators were investigated and optimized. Finally, the structure of the polymer was characterized by using Fourier transform infrared spectroscopy and scanning electron microscopy. To obtain objective results, non‐imprinted molecular polymers prepared under the same conditions were also characterized. The adsorption quantity of the polymer was measured by high‐performance liquid chromatography. Under the optimum conditions, the maximum adsorption capacity of glycyrrhizic acid approached 15 mg/g, and the separation degree was as high as 2.5. The adsorption kinetics could be well described by a pseudo‐first‐order model, while the thermodynamics of the adsorption process could be described by the Langmuir model.     

Synthesis and spectroscopic investigation of π‐conjugated (E)‐enyne polycarbazole with different organo‐metallic catalysts from 3,6‐diethynyl‐9‐(2‐ethylhexyl)carbazole

In the present study, a new (E)‐rich‐enyne π‐conjugated polymer containing a carbazole was designed and synthesized. Two different synthesis methods of poly[N‐(2‐ethylhexyl)‐3,6‐carbazolyleneethynylene‐(E)‐vinylene] (PCZEV) have been prepared from 3,6‐diethynyl‐9(2‐ethylhexyl)carbazole by using the palladium‐carbene‐catalyzed reaction and/or by using the organolanthanide‐catalyzed reaction leading to well‐defined polymer, and their general properties were studied. Compared to poly[N‐(2‐ethylhexyl)‐3,6‐carbazolyleneethynylene] (PCE), the UV‐vis absorption and photoluminescence of the PCZEV was red‐shifted, which indicates the extension of conjugation length. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2434–2442, 2009     

One-pot enyne metathesis/Diels-Alder reaction for the construction of highly functionalized novel polycyclic aza-compounds

Various tricyclic dienes were synthesized via enyne metathesis using the first generation Grubbs catalyst. The enyne metathesis proceeded smoothly in refluxing CH₂Cl₂ with a low catalyst loading (3.0 mol %), giving good yields (72-89%) of the tricyclic products 6 and 16. The resulting 1,3-dienes are suitable precursors of polycyclic structures via a Diels-Alder process. One-pot RCM/Diels-Alder reactions of the enyne products with dienophiles proceeded smoothly to afford polycyclic compounds as a single cycloadduct. The structures of the Diels-Alder adducts were determined by ¹H NMR spectra and X-ray analysis. The cycloadducts were formed via the approach of the dienophiles towards the diene in endo mode.     

Cope elimination and complexation of poly(dimethylaminoethyl methacrylate N-oxide)

Poly(dimethylaminoethyl methacrylate N-oxide) (poly(DMAEMNO)) was prepared by oxidation of poly(dimethylaminoethyl methacrylate) with hydrogen peroxide in methanol. From thermogravimetric and IR spectroscopic investigations Cope elimination of amine oxide group in poly(DMAENO) was found to occur at 120–150°C. The postpolymerization of partially pyrolyzed polymer carrying vinyl ester group as pendant was performed with azobisisobutyronitrile at 60°C in methanol to give cross-linked polymer that was found to form hydrogel. Poly(DMAEMNO) gave metal–polymer complexes with CuCl₂, ZnCl₂, and CoCl₂. Cobalt–polymer complex had a constitution of 1:2 of metal ion to amine oxide group, while copper– and zinc–polymer complexes seemed to have structures of 1:1 and 1:2 of metal ion to amine oxide group. Furthermore, polymer complexes of poly(DMAEMNO) with poly(methacrylic acid) and poly(acrylic acid) were found to be formed by mixing aqueous solutions of both polymers and also by radical polymerization of the acid monomers in the presence of poly(DMAEMNO). From elemental analysis, thermogravimetric investigation, and measurement of turbidity it was concluded that the resulting polymer–polymer complexes contained more than one acid monomer unit per one N-oxide unit.     

Anionic living polymerization of styrenes containing electron-withdrawing groups

Six styrene derivatives containing electron-withdrawing groups were synthesized and polymerized with anionic initiators in THF to afford stable anionic living polymers. The electron-withdrawing substituents are N,N-dialkylamide(1), N-alkylimino(2), oxazoline(3), tert-butyl ester(4), N,N-dialkylsulfonamide(5) and cyano(6) moieties. The polymers obtained have predictable molecular weights and narrow molecular weight distributions. The respective postpolymerizations proceeded with quantitative efficiency indicating that each polymer chain end retained the propagating reactivity. However, the resulting living polymers could not initiate the polymerizations of styrene and isoprene. On the other hand, the styrene derivatives(5 and 6) were polymerized with weak nucleophilic initiators, such as living polymer of tert-butyl methacrylate. These results suggest that the electron-withdrawing groups stabilize the living ends and also activate the respective monomers for anionic polymerization. The substitution effect reflects on the ¹³C NMR chemical shift of β-carbon of each vinyl group. The signal of the β-carbon appeared at lower magnetic field than that of styrene indicating electron deficiency on the carbon-carbon double bond of these monomers.     

The synthesis and solution properties of some rigid-chain,water-soluble polymers: Poly[N,N′-(sulfo-phenylene)phthalamide]s and poly[N,N′-(sulfo-p-phenylene)pyromellitimide]

Poly[N,N′-(sulfo-phenylene)phthalamid]es and poly[N,N′-(sulfo-p-phenylene)pyromellitimide] were prepared in water-soluble form and were found to have unique solution properties, similar in some respects to xanthan. The polymer most investigated, poly[N,N′-(sulfo-p-phenylene)terephthalamide] (PPT-S), is produced as the dimethylacetamide (DMAC) salt by the solution polymerization of 2,5-diaminobenzenesulfonic acid with terephthaloyl chloride in DMAC containing LiCl. The isolated polymer requires heating in water to dissolve; the resulting cooled solutions are viscous or gels at concentrations as low as 0.4%. They are highly birefringent, exhibit circular dichroism properties, and are viscosity-sensitive to salt. Solutions of this polymer mixed with those of guar or hydroxyethyl cellulose give significantly enhanced viscosity. The polymer is relatively low molecular weight, ca. 5000 estimated from viscosity data. Some meta and para isomeric analogs of PPT-S were prepared; these polymers have similar properties except they are more soluble in water, and higher concentrations are required to obtain significant viscosity. Poly[N,N′-(sulfo-p-phenylene) pyromellitimide] (PIM-S) was prepared similarly from 2,5-diaminobenzenesulfonic acid and pyromellitic dianhydride. Its aqueous solution properties are similar to those of PPT-S. It appears that these relatively low-molecular-weight rigid-chain polymers associate in water to form a network that results in viscous solutions at low concentrations.