Solid‐State Emission of the Anthracene‐o‐Carborane Dyad from the Twisted‐Intramolecular Charge Transfer in the Crystalline State

The emission process of the o ‐carborane dyad with anthracene originating from the twisted intramolecular charge transfer (TICT) state in the crystalline state is described. The anthracene‐o ‐carborane dyad was synthesized and its optical properties were investigated. Initially, the dyad had aggregation‐ and crystallization‐induced emission enhancement (AIEE and CIEE) properties via the intramolecular charge transfer (ICT) state. Interestingly, the dyad presented the dual‐emissions assigned to both locally excited (LE) and ICT states in solution. From the mechanistic studies and computer calculations, it was indicated that the emission band from the ICT should be attributable to the TICT emission. Surprisingly, even in the crystalline state, the TICT emission was observed. It was proposed from that the compact sphere shape of o ‐carborane would allow for rotation even in the condensed state.     

Nondestructive Photoluminescence Read‐Out by Intramolecular Electron Transfer in a Perylene Bisimide‐Diarylethene Dyad

A novel, highly stable photochromic dyad 3 based on a perylene bisimide (PBI) fluorophore and a diarylethene (DAE) photochrome was synthesized and the optical and photophysical properties of this dyad were studied in detail by steady‐state and time‐resolved ultrafast spectroscopy. This photochromic dyad can be switched reversibly by UV‐light irradiation of its ring‐open form 3 o leading to the ring‐closed form 3 c , and back reaction of 3 c to 3 o by irradiation with visible light. Solvent‐dependent fluorescence studies revealed that the emission of ring‐closed form 3 c is drastically quenched in solvents of medium (e.g., chloroform) to high (e.g., acetone) polarities, while the emission of the ring‐open form 3 o is appreciably quenched only in highly polar solvents like DMF. The strong fluorescence quenching of 3 c is attributed to a photoinduced electron‐transfer (PET) process from the excited PBI unit to ring‐closed DAE moiety, as this process is thermodynamically highly favorable with a Gibbs free energy value of ?0.34 eV in dichloromethane. The electron‐transfer mechanism for the fluorescence quenching of ring‐closed 3 c is substantiated by ultrafast transient measurements in dichloromethane and acetone, revealing stabilization of charge‐separated states of 3 c in these solvents. Our results reported here show that the new photochromic dyad 3 has potential for nondestructive read‐out in write/read/erase fluorescent memory systems.     

One‐step synthesis of polymer micro‐tubes tethered by polymer nanowire networks via RAFT polymerization of N,N′‐methylene bisacrylamide xerogel fibers in toluene and ethanol mixed solution

In the mixed solution of toluene and ethanol, polymer micro‐tubes (PMTs) tethered by polymer nanowire networks (PTPWNs) were fabricated facilely via one‐step reversible addition fragmentation chain transfer (RAFT) polymerization by taking N,N′‐methylene bisacrylamide (MBA) xerogel fibers as both template and monomer source. The products were analyzed by FTIR, SEM, TEM, surface area and porosity analyzer, and contact angle tester. The results indicated that PTPWNs were obtained as the sole product at ethanol content of 1.0 wt %. As the content of ethanol increases from 0 to 1.0 wt %, the specific surface area of the products became higher, indicating more polymer nanowire networks (PWNs) on the tubes. At ethanol contents of 1.5 wt % and 2.0 wt %, some particles were also obtained besides PTPWNs. The formation process of PTPWNs was studied by analyzing the products obtained at different reaction time. The results revealed that PTPWNs were formed by two steps, PMTs were formed quickly and then PWNs formed in the solution tethered to the tubes. Moreover, the effect of RAFT agent on the morphologies of the products revealed that PTPWNs could be obtained via RAFT polymerization at suitable dosage of RAFT agent, while polymer particles were generated via conventional free radical polymerization. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 1862–1868     

Lipase‐catalyzed ring‐opening polymerization of 6(S)‐methyl‐morpholine‐2,5‐dione

Lipase‐catalyzed ring‐opening bulk polymerizations of 6(S)‐methyl‐morpholine‐2,5‐dione (MMD) were investigated. Selected commercial lipases were screened as catalysts for MMD polymerization at 100 °C. Polymerizations catalyzed with 10 wt % porcine pancreatic lipase type II crude (PPL), lipase from Pseudomonas cepacia, and lipase type VII from Candida rugosa resulted in MMD conversions of about 75% in 3 days and in molecular weights ranging from 8200 to 12,100. Poly(6‐methyl‐morpholine‐2,5‐dione) [poly(MMD)] had a carboxylic acid group at one end and a hydroxyl group at the other end. However, lipase from Mucor javanicus showed lower catalytic activity for the polymerization. During the polymerization, racemization of the lactate residue took place. PPL was selected for further studies. The rate of polymerization increased with increasing PPL concentration under otherwise identical conditions. When the PPL concentration was 5 or 10 wt % with respect to MMD, a conversion of about 70% was reached after 6 days or 1 day, respectively, whereas for a PPL concentration of 1 wt %, the conversion was less than 20% even after 6 days. High concentrations of PPL (10 wt %) resulted in high number‐average molecular weights (<3 days); with a lower concentration of PPL, lower molecular weight poly(MMD) was obtained. The concentration of water was an important factor that controlled not only the conversion but also the molecular weight. With increasing water content, enhanced polymerization rates were achieved, whereas the molecular weight of poly(MMD) decreased. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3030–3039, 2005     

A novel donor–donor polymeric dyad of Poly(3‐hexylthiophene‐block‐oligo(anthracene‐9,10‐diyl): Synthesis,solid‐state packing,and electronic properties

A new polymeric dyad of oligo‐anthracene‐block‐poly(3‐hexylthiophene) (Oligo‐ANT‐b‐P3HT) has been synthesized as a donor–donor dyad building block for organic photovoltaics. The polymer dyad and oligomer of anthracene‐9,10‐diyl (Oligo‐ANT) are prepared by Grignard Metathesis. The higher order of crystallinity and molecular chains ordering at solid phase reveal the intrinsic optical and electrical properties of polymeric dyad resulting in relatively higher light harvesting ability compared to the oligo(anthracene‐9,10‐diyl). The UV‐visible spectrum of (Oligo‐ANT‐b‐P3HT) in solution shows broad absorption with two sets of absorption from both anthracene and thiophene core units, covering a wide range of the visible spectrum. The test devices of the blends of polymeric dyad with fullerene C₆₁ (PCBM) show improved photovoltaic performance with a power conversion efficiency of 3.26% upon subjecting to pre‐fabrication thermal treatments. With optimized morphology of the interpenetrating network and the shorter fluorescence lifetime of the annealed dyad/PCBM blends, the effective charge transfer from the donor dyad to PCBM has evidenced. Thus, these studies will allow further synthetic advances to make potential high crystalline polymeric dyads with significantly improved light harvesting capability. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 3032–3045     

Lipase‐Catalyzed Ring‐Opening Polymerization of 3(S)‐sec‐Butylmorpholine‐2,5‐dione

Lipase‐catalyzed ring‐opening bulk polymerizations of 3(S)‐sec‐butylmorpholine‐2,5‐dione (BMD) were investigated. Selected commercial lipases were screened as catalysts for BMD polymerization at 110°C. Polymerizations catalyzed with 10 wt.‐% of lipase PPL and PC result in BMD conversions of about 70% and in molecular weights of the products ranging from 5 500 to 10 700. Lipases MJ, CR and ES showed lower catalytic activities for the polymerization of BMD. Poly(3‐sec‐butylmorpholine‐2,5‐dione) has a carboxylic acid group at one end and a hydroxy group at the other end. During the polymerization racemization of the isoleucine residue takes place. Lipase PPL was selected for a more detailed study. The apparent rate of polymerization increases with increasing PPL concentration when the polymerization temperature is 110°C. When the PPL concentration is 5 and 10 wt.‐% with respect to the monomer, a conversion of about 70% is reached after 5 d and 3 d, respectively, while for a PPL concentration of 1 wt.‐% the conversion is less than 7% even after 6  d. High concentrations of PPL (10 wt.‐%) result in high M_n values (< 4  d). The highest molecular weight poly(BMD), M_n = 19 900, resulted from a polymerization conducted at 120°C with 5 wt.‐% PPL for 6 d. The general trend observed by varying the polymerization temperature is as follows: (i) monomer conversion and M_n increase with increasing reaction temperature from 110 to 125°C, (ii) monomer conversion and M_n decrease with an increase in reaction temperature from 125 to 130°C. Water content was found to be an important factor that controls both the conversion and the molecular weight. With increasing water content, enhanced polymerization rates are achieved while the molecular weight of poly(BMD) decreases.     

Efficient Intramolecular Charge Transfer in Oligoyne‐Linked Donor–π–Acceptor Molecules

Studies are reported on a series of triphenylamine–(C?C)_n–2,5‐diphenyl‐1,3,4‐oxadiazole dyad molecules (n=1–4, 1 , 2 , 3 and 4 , respectively) and the related triphenylamine‐C₆H₄–(C?C)₃–oxadiazole dyad 5 . The oligoyne‐linked D–π–A (D=electron donor, A=electron acceptor) dyad systems have been synthesised by palladium‐catalysed cross‐coupling of terminal alkynyl and butadiynyl synthons with the corresponding bromoalkynyl moieties. Cyclic voltammetric studies reveal a reduction in the HOMO–LUMO gap in the series of compounds 1 – 4 as the oligoyne chain length increases, which is consistent with extended conjugation through the elongated bridges. Photophysical studies provide new insights into conjugative effects in oligoyne molecular wires. In non‐polar solvents the emission from these dyad systems has two different origins: a locally excited (LE) state, which is responsible for a π*→π fluorescence, and an intramolecular charge transfer (ICT) state, which produces charge‐transfer emission. In polar solvents the LE state emission vanishes and only ICT emission is observed. This emission displays strong solvatochromism and analysis according to the Lippert–Mataga–Oshika formalism shows significant ICT for all the luminescent compounds with high efficiency even for the longer more conjugated systems. The excited‐state properties of the dyads in non‐polar solvents vary with the extent of conjugation. For more conjugated systems a fast non‐radiative route dominates the excited‐state decay and follows the Engelman–Jortner energy gap law. The data suggest that the non‐radiative decay is driven by the weak coupling limit.     

A New V‐Shaped Organic Fluorescent Compound Integrated with Crystallization‐Induced Emission Enhancement and Intramolecular Charge Transfer

The emission behavior of a new V‐shaped organic fluorescent compound (p,p′‐bis(2‐aryl‐1,3,4‐oxadiazol‐5‐yl)diphenyl sulfone ( OZA-SO ), consisting of diethylamino (donor) and sulfone (acceptor) units, has been studied in various polar solvents and with different morphologies. As expected, there is the gradual transition from the locally excited state to the intramolecular charge‐transfer (ICT) state with the increasing solvent polarity. The photoluminescence intensity of OZA-SO initially decreases with a low water fraction (f_w), owing to ICT effect, and then increases with a high f_w, owing to crystallization‐induced emission enhancement. At the same time, the fluorescence lifetime of OZA-SO increases from 0.062 ns in dimethylformamide (DMF) to 5.80 ns in a solution containing 90 % water, and then to 7.49 ns in a solution containing 60 % water. Furthermore, the solid‐state emission of OZA-SO can be tuned reversibly from green to yellow by fuming/grinding or fuming/heating owing to morphological changes. This color‐switchable feature of OZA-SO may have potential applications in optical‐recording and temperature‐sensing materials.     

Improved microfiltration and bacteria removal performance of polyethersulfone membranes prepared by modified vapor‐induced phase separation

Polyethersulfone (PES) microfiltration membranes were fabricated by a combined vapor‐induced phase separation and wet phase separation method. The effect of different non‐solvent additives in casting solution, ie, acetone, diethylene glycol, and triethylene glycol (TEG) was investigated on the membrane morphology and performance. Scanning electron microscopy images showed that the membrane containing TEG additive had a skinless symmetric structure with well interconnected pores. The permeability of the PES/PVP/TEG membranes increased by decreasing PES and TEG and increasing PVP concentration. Bacteria removal performance of the prepared membranes was investigated by the filtration of E. coli suspension. The membrane made from casting solution containing 15 wt.% PES, 16 wt.% PVP, and 20wt.% TEG showed a pure water flux of ~ 5370 L/m² h at low transmembrane pressure of 10 psi and 100% bacteria removal efficiency. The results of in vitro cytotoxicity test and cell viability assay showed non‐toxic nature of the prepared membranes.     

High solids TEMPO‐mediated radical semibatch emulsion polymerization of styrene

A bicomponent initiation system consisting of 2,2,6,6‐tetramethylpiperidine‐N‐oxyl (TEMPO) and the water soluble initiator potassium persulfate (KPS) was used to develop a robust and versatile semibatch emulsion polymerization process to obtain polystyrene (PS) latexes with solids contents of 5–40 wt %. A window of operating conditions was found that yielded high conversion (>95%) stable latexes and well controlled polymers, overcoming limitations found in previous attempts at developing similar processes using TEMPO. The critical parameters studied were surfactant concentration, monomer concentration in the nucleation step and the monomer feed rate in the semibatch step. Methyl acrylate (MA) was used in the nucleation step to improve the nitroxide efficiency (N_Eff). Latexes having molecular weight distribution (MWD) with dispersity (?) lower than 1.5, average particle size (D_p) from ≈32 to ≈500 nm, nitroxide efficiencies N_Eff up to ≈1.0 and monomer conversions >90% were obtained in less than 12 h with solids contents up to 40 wt %. These results constitute a significant advance over prior efforts in TEMPO‐mediated polymerization in aqueous dispersions. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 49–62     

Characteristic properties of film prepared from poly(L‐lactide)‐grafted dextran of a relatively high sugar unit content as a degradable biomaterial

To develop novel biomedical soft materials with degradability, amphiphilic poly(L ‐lactide)‐grafted dextrans (Dex‐g‐PLLAs) of relatively high sugar unit contents were synthesized with the trimethylsilyl protection method. The characteristic properties of solution‐cast films prepared from the obtained Dex‐g‐PLLAs were investigated. The water absorption and degradation rate of the Dex‐g‐PLLA films increased with increasing sugar unit content. The morphology of the bulk phase and top surface of the Dex‐g‐PLLA films was evaluated with transmission electron microscopy and atomic force microscopy, respectively. The bulk phase of the Dex‐g‐PLLA films with a sugar unit content of 16–25 wt % was found by transmission electron microscopy to form a lamellar type of phase‐separated structure composed of approximately 80–100‐nm‐wide nanodomains because of their amphiphilic and branched structures. The hydrophobic top surface for a Dex‐g‐PLLA film with a sugar unit content of 25 wt % covered with PLLA segments was confirmed by atomic force microscopy phase images to be easily converted to a wettable top surface covered with hydrophilic dextran aggregates showing an 8–10‐nm‐wide honeycomb pattern by means of annealing in water. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6402–6409, 2006     

AIE Fluorescent Gelators with Thermo‐, Mechano‐, and Vapochromic Properties

A series of aggregation‐induced emission (AIE) fluorescent gelators (TPE‐C_n‐Chol) were synthesized by attaching tetraphenylethylene (TPE) to cholesterol through an alkyl chain. The properties of the gel, nano‐/microaggregate, and condensed phases were studied carefully. TPE‐C_n‐Chol molecules form AIE fluorescent gels in acetone and in DMF. Their fluorescence can be reversibly switched between the “on” and “off” states by a gel–sol phase transition upon thermal treatment. The AIE properties of aggregated nano‐/microstructures in acetone/water mixtures with different water fractions were studied by using fluorescence spectrometry and scanning electron microscopy (SEM). In different acetone/water mixtures, the TPE‐C_n‐Chol molecules formed different nano‐/microaggregates, such as rodlike crystallites and spherical nanoparticles that showed different fluorescence colors. Finally, the condensed phase behavior of TPE‐C_n‐Chol was studied by using polarizing microscopy (POM), differential scanning calorimetry (DSC), fluorescence spectrometry, fluorescence optical microscopy, and wide‐angle X ray scattering (WAXS). The clover‐shaped TPE unit introduced into the rodlike cholesterol mesogen inhibits not only the formation of a liquid‐crystal phase but also recrystallization upon cooling from the isotropic liquid phase. Very interestingly, TPE‐C_n‐Chol molecules in the condensed state change their fluorescence color under external stimuli, such as melting, grinding, and solvent fuming. The phase transition is the origin of these thermo‐, mechano‐, and vapochromic properties. These findings offer a simple and interesting platform for the creation of multistimuli‐responsive fluorescent sensors.     

Synthesis and properties of poly(isobutyl methacrylate‐co‐butanediol dimethacrylate‐co‐methacryl polyhedral oligomeric silsesquioxane) nanocomposites

Poly[isobutyl methacrylate‐co‐butanediol dimethacrylate‐co‐3‐methacrylylpropylheptaisobutyl‐T8‐polyhedral oligomeric silsesquioxane] [P(iBMA‐co‐BDMA‐co‐MA‐POSS)] nanocomposites with different crosslink densities and different polyhedral oligomeric silsesquioxane (MA‐POSS) percentages (5, 10, 15, 20, and 30 wt %) were synthesized by radical‐initiated terpolymerization. Linear [P(iBMA‐co‐MA‐POSS)] copolymers were also prepared. The viscoelastic properties and morphologies were studied by dynamic mechanical thermal analysis, confocal microscopy, and transmission electron microscopy (TEM). The viscoelastic properties depended on the crosslink density. The dependence of viscoelastic properties on MA‐POSS content at a low BDMA loading (1 wt %) was similar to that of linear P(iBMA‐co‐MA‐POSS) copolymers. P(iBMA‐co‐1 wt % BDMA‐co‐10 wt % MA‐POSS) exhibited the highest dynamic storage modulus (E′) values in the rubbery region of this series. The 30 wt % MA‐POSS nanocomposites with 1 wt % BDMA exhibited the lowest E′. However, the E′ values in the rubbery region for P(iBMA‐co‐3 wt % BDMA‐co‐MA‐POSS) nanocomposites with 15 and 30 wt % MA‐POSS were higher than those of the parent P(iBMA‐co‐3 wt % BDMA) resin. MA‐POSS raised the E′ values of all P(iBMA‐co‐ 5 wt % BDMA‐co‐MA‐POSS) nanocomposites in the rubbery region above those of P(iBMA‐co‐5 wt % BDMA), but MA‐POSS loadings < 15 wt % had little influence on glass‐transition temperatures (T_g's) and slightly reduced T_g values with 20 or 30 wt % POSS. Heating history had little influence on viscoelastic properties. No POSS aggregates were observed for the P(iBMA‐co‐1 wt % BDMA‐co‐MA‐POSS) nanocomposites by TEM. POSS‐rich particles with diameters of several micrometers were present in the nanocomposites with 3 or 5 wt % BDMA. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 355–372, 2005     

Initiator‐fragment incorporation radical copolymerization of divinylbenzene and N‐isopropylacrylamide with dimethyl 2,2′‐azobisisobutyrate: Formation of soluble hyperbranched polymer nanoparticle

The copolymerization of divinylbenzene (DVB) and N‐isopropylacrylamide (NIPAm) with dimethyl 2,2′‐azobisisobutyrate of a concentration as high as 0.50 mol/L proceeded homogeneously without any gelation at 80 °C in N,N‐dimethylformamide, where the concentrations of DVB and NIPAm were 0.15 and 0.50 mol/L. The copolymer yield increased with time and leveled off over 50 min. Although DVB was consumed more rapidly than NIPAm, both comonomers were completely consumed in 50 min. The homogeneous polymerization system at 80 °C involved electron spin resonance‐observable propagating polymer radicals, the total concentration of which increased with time. The resulting copolymer was soluble in tetrahydrofuran, chloroform, acetone, ethyl acetate, acetonitrile, N,N‐dimethylformamide, dimethyl sulfoxide, and methanol, but insoluble in benzene, n‐hexane, and water. The copolymer showed an upper critical solution temperature (50 °C on cooling) in a methanol–water [11:3 (v/v)] mixture. Dimethyl 2,2′‐azobisisobutyrate fragments as high as 37–45 mol % were incorporated as terminal groups in the copolymers through initiation and primary radical termination. The contents of DVB and NIPAm were 10–30 mol % and 30–50 mol %, respectively. The intrinsic viscosity of the copolymer was very low (0.09 dL/g) at 30 °C in tetrahydrofuran despite high weight‐average molecular weight (1.2 × l0⁶ by multi‐angle laser light scattering). These results indicate that the copolymer was of hyperbranched structure. By transmission electron microscopy observation, the individual copolymer molecules were visualized as nanoparticle of 6–20 nm. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 1609–1617, 2004     

Ultrasound‐assisted dispersive liquid–liquid microextraction combined with gas chromatography‐mass spectrometry in negative chemical ionization mode for the determination of polybrominated diphenyl ethers in water

A simple and economical method for the determination of eight polybrominated diphenyl ethers (BDE‐28, 47, 99, 100,153,154,183, and 209) in water was developed. This method involves the use of ultrasound‐assisted dispersive liquid–liquid microextraction combined with GC‐MS in negative chemical ionization mode. Various parameters affecting the extraction efficiency, including the type and volume of extraction and dispersive solvents, salt concentration, extraction time, and ultrasonic time, were investigated. A volume of 1.0 mL of acetone (dispersive solvent) containing 10 μL tetrachloroethylene (extraction solvent) was injected into 5.0 mL of water samples and then emulsified by ultrasound for 2.0 min to produce the cloudy solution. Under the optimal condition, the enrichment factors for the eight PBDEs were varied from 845‐ to 1050‐folds. Good linearity was observed in the range of 1.0–200 ng L^?1 for BDE‐28, 47, 99, and 100; 5.0–200 ng L^?1 for BDE‐153, 154, and 183; and 5.0–500 ng L^?1 for BDE‐209. The RSD values were in the range of 2.5–8.4% (n = 5) and the LODs ranged from 0.40 to 2.15 ng L^?1 (S/N = 3). The developed method was applied for the determination of eight BPDEs in the river and lake water samples, and the mean recoveries at spiking levels of 5.0 and 50.0 ng L^?1 were in the range of 70.6–105.1%.     

Aqueous self‐assembly of pullulan‐b‐poly(2‐ethyl‐2‐oxazoline) double hydrophilic block copolymers

The self‐assembly of a novel double hydrophilic block copolymer in water without the application of external triggers is described, namely pullulan‐b‐poly(2‐ethyl‐2‐oxazoline) (Pull‐b‐PEtOx). The biomacromolecules, Pull (8–38 kg mol^?1), is modified and conjugated to biocompatible PEtOx (22 kg mol^?1) via modular conjugation. Moreover, the molecular weight of the Pull blocks are varied to investigate the effect of molecular weight on the self‐assembly behavior. Spherical particles with sizes between 300 and 500 nm are formed in diluted aqueous solution (0.1–1.0 wt %) as observed via dynamic light scattering and static light scattering. Additionally, cryo scanning electron microscopy and laser scanning confocal microscopy are performed to support the finding from light scattering. The block ratio study shows an optimum ratio of Pull and PEtOx of 0.4/0.6 for self‐assembly in water in the concentration range of 0.1–1.0 wt %. At higher concentrations of 20 wt %, vesicular structures with sizes above 1 µm can be observed via optical microscopy. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55 , 3757–3766     

High water content clay–nanocomposite hydrogels incorporating guanidinium‐pendant methacrylamide: Tuning of mechanical and swelling properties by supramolecular approach

Novel clay–polymer composite hydrogels with high water content (up to 98 wt %) are developed, in which mechanical properties are reinforced by the formation of multiple ion‐pairs between the polymer chains and clay nanosheets (CNS). When a small amount of guanidinium‐pendant methacrylamide (0.1–0.2 wt %) is copolymerized with a neutral monomer (0.5–2.0 wt %) in an aqueous dispersion of CNS (1.0–3.0 wt %), a self‐standing hydrogel with satisfactory mechanical toughness and elasticity results, despite its high water content (95–98 wt %). The mechanical properties and swelling behaviors of the hydrogels can be tuned by the amount of the guanidinium‐pendant acrylamide. A systematic study indicates that the ion pairs, formed between the guanidinium groups in the polymer chains and the oxyanions on the surfaces of the CNS, serve as crosslinking points in the three‐dimensional network developed in these hydrogels. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 839–847     

Synthese von Sulfolenobilinen und deren Cyclisierung zu Chlorinatozink‐Fulleren‐Dyaden

Synthesis of Sulfolenobilins and Their Cyclization Directed to Chlorinatozinc‐Fullerene Dyads A novel chlorinatozinc‐fullerene dyad 18 was synthesized to model the photosynthetic reaction center. The synthetic key step for the formation of the dyad 18 is an unusual one‐pot reaction of the (sulfolenobilinato)nickel rac‐ 16a , b with concomitant generation of the chlorin macrocycle and linkage to the [5,6]fullerene‐C₆₀‐I_h. This one‐pot reaction is a complex cascade of single reaction steps with a total yield of 32% and an average yield of 83% for the individual steps. The chlorinatozinc‐fullerene dyad is so far one of three examples that contain chlorin moieties, the chromophores in naturally occurring photosynthetic systems.     

PEGDA‐based luminescent polymers prepared by frontal polymerization

Frontal polymerization (FP) of poly(ethylene glycol) diacrylate (PEGDA) was carried out using benzoyl peroxide (BPO) as radical initiator. In addition, a pyrene containing monomer, 1‐pyrenebutyl acrylate (PyBuAc), was incorporated as a fluorescent probe in order to obtain luminescent materials with different chromophore contents. The resulting polymers were characterized by FT‐IR spectroscopy in the solid state and their thermal properties were determined by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Moreover, the optical properties of these materials were studied by absorption and fluorescence spectroscopy. The maximum amount of the incorporated pyrene‐containing monomer into the polymer matrix was limited to 1 wt % by the polymerization process. The obtained labeled polymers poly(PEGDA‐co‐PyBuAc) exhibited a broad absorption band at 345 nm. The fluorescence spectra of these polymers exhibited mainly “monomer emission” so that no excimer emission was observed. It is possible to tune the color of the emitted light by varying the pyrene content in the samples. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 2890–2897