Stable,Hydroxyl Functional Polycarbonates With Glycerol Side Chains Synthesized From CO2 and Isopropylidene(glyceryl glycidyl ether)

A series of functional polycarbonates, poly((isopropylidene glyceryl glycidyl ether)‐co‐(glycidyl methyl ether) carbonate) (P((IGG‐co‐GME) C)) random copolymers with different fractions of 1,2‐isopropylidene glyceryl glycidyl ether (IGG) units, is synthesized. After acidic hydrolysis of the acetal protecting groups, a new type of functional polycarbonate prepared directly from CO₂ and glycerol is obtained, namely poly((glyceryl glycerol)‐co‐(glycidyl methyl ether) carbonate) (P((GG‐co‐GME) C)). All hydroxyl functional samples exhibit monomodal molecular weight distributions with PDIs between 2.5 and 3.3 and M _n between 12 000 and 25 000 g mol⁻¹. Thermal properties reflect the amorphous structure of the polymers. The materials are stable in bulk and solution.     

Preparation of amphiphilic copolymers for covalent loading of paclitaxel for drug delivery system

A novel drug‐polymer conjugate was prepared by the copper‐catalyzed azide–alkyne cycloaddition reaction between an azide‐functional diblock copolymer and an alkyne‐functional paclitaxel (PTX). The well‐defined azide‐functional diblock copolymer, poly(ethylene glycol) (PEG)‐b‐P(OEGEEMA‐co‐AzPMA), was synthesized via the atom transfer radical polymerization of oligo(ethylene glycol) ethyl ether methacrylate (OEGEEMA) and 3‐azidopropyl methacrylate (AzPMA), using PEG‐Br as macroinitiator and CuBr/PMDETA as a catalytic system. The alkyne‐functional PTX was covalently linked to the copolymer via a click reaction, and the loading content of PTX could be easily tuned by varying the feeding ratio. Transmission electron microscopy and dynamic light scattering results indicated that the drug loaded copolymers could self‐assemble into micelles in aqueous solution. Moreover, the drug release behavior of PEG‐b‐P(OEGEEMA‐co‐AzPMA‐PTX) was pH dependent, and the cumulative release amount of PTX were 50.0% at pH 5.5, which is about two times higher than that at pH 7.4. The in vitro cytotoxicity experimental results showed that the diblock copolymer was biocompatible, with no obvious cytotoxicity, whereas the PTX‐polymer conjugate could efficiently deliver PTX into HeLa and SKOV‐3 cells, leading to excellent antitumor activity. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 366–374     

Theoretical study of the internal elimination reactions of xanthate precursors

The gas‐phase internal elimination (E_i) reaction of ethyl xanthate (CH₃‐CH₂‐S‐CS‐O‐CH₃) has been investigated by means of Hartree–Fock, second‐order Møller–Plesset, and density functional theory (DFT) using the Becke three‐parameter Lee–Yang–Parr (B3LYP) functional and the modified Perdew–Wang one‐parameter model for kinetics (MPW1K). Considerable differences between the ground‐ and transition‐state geometries and the calculated activation energies are observed from one approach to the other, which justifies first a careful calibration of the methods against the results of benchmark CCSD(T) calculations. Compared with these, DFT calculations along with the MPW1K functional are found to be an appropriate choice for describing the E_i reaction of xanthate precursors. The precursor conformation and the transition states involved in the internal conversion of xanthate precursors of cyano derivatives of ethylene, and of cis‐ and trans‐stilbene, are then characterized in detail by means of this functional. © 2003 Wiley Periodicals, Inc. J Comput Chem 24: 2023–2031, 2003     

Postmodification of poly(9‐alkyl‐9H‐carbazole‐2,7‐diyl)s as a route to new main‐chain‐functionalized carbazole polymers

The postmodification of poly[9‐(2‐hexyldecyl)‐9H‐carbazole‐2,7‐diyl] ( P1 ) upon its reaction with N‐bromosuccinimide affords exclusive and full bromination of the 3,6‐positions of the carbazole repeat units to yield poly[3,6‐dibromo‐9‐(2‐hexyldecyl)‐9H‐carbazole‐2,7‐diyl] ( P2 ). Brominated polymer P2 can be used as a precursor for further functionalization at the 3,6‐positions with the desired functional group to afford other useful polymers. Polymer P2 has hence been reacted with copper(I) cyanide to afford poly[3,6‐dicyano‐9‐(2‐hexyldecyl)‐9H‐carbazole‐2,7‐diyl] ( P3 ). Full substitution of the bromide groups with nitrile‐functional groups has been achieved. The preparation and structural characterization of polymers P2 and P3 are presented together with studies on their electronic conjugation and photoluminescence properties. Cyclic voltammetry studies on polymer P3 indicate that the new polymer is easier to reduce (n‐dope) but more difficult to oxidize than its unsubstituted counterpart ( P1 ) as a result of the introduction of the electron‐withdrawing nitrile‐functional groups at the 3,6‐positions on the carbazole repeat units on the polymer chains. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3336–3342, 2006     

Synthesis and phase‐separation behavior of α,ω‐difunctionalized diblock copolymers

A series of diblock copolymers of n‐pentyl methacrylate and methyl methacrylate (PPMA/PMMA BCP) with one or two terminal functional groups was prepared by sequential anionic polymerization of PMA and MMA using an allyl‐functionalized initiator and/or and end‐capping with allyl bromide. Allyl functional groups were successfully converted into OH groups by hydroboration. The morphology in bulk was examined by temperature‐dependent small‐angle X‐ray measurements (T‐SAXS) and transmission electron microscopy (TEM) showing that functional groups induced a weak change in d‐spacings L₀ as well as in the thermal expansion behavior. T‐SAXS proved that the lamellar morphologies were stable over multiple heating/cooling cycles without order‐disorder transition (ODT) until 300 °C. While non‐functionalized BCP formed parallel lamellae morphologies, additional OH‐termination at the PMMA block forced in very thin films (ratio between film thickness and lamellar d‐spacing below 1) the generation of perpendicular lamellae morphology through the whole film thickness, as shown by Grazing‐incidence small‐angle X‐ray scattering experiments (GISAXS) measurements. Functionalized BCP were successfully used in thin films as templates for silica nanoparticles in an in‐situ sol–gel process. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Theoretical Investigation on the Electron and Energy Transfer between Peripheral Carrier Transport Groups and Central Chromophores in Electroluminescent Materials

The molecular materials with structures of luminescent core and peripheral carrier groups (e.g. carbazoles), have exhibited high‐performance in organic light‐emitting diodes (OLEDs). Present work is to understand the basic process of electronic and energy exchange between the peripheral functional groups and the central core through quantum chemical analysis. As an example, 4,7‐bis(9,9‐bis(6‐(9H‐carbazol‐9‐yl)hexyl)‐9H‐fluoren‐2‐yl)benzo[c]‐[1,2,5]thiadiazole (TCBzC) is investigated in regards to optoelectronic properties using density functional theory (DFT). The results suggest that the forbidden transition from peripheral carbazole to the central chromophore core makes for separated electrical and optical properties, and high performance electroluminescence (EL) is mainly attributed to the energy‐transfer from carbazoles to the fluorene derivative core     

Modular Synthesis of Functional Block Copolymers

Summary: The free‐radical addition of ω‐functional mercaptans to the vinyl double bonds of 1,2‐polybutadiene‐block‐poly(ethylene oxide) copolymers was used for modular synthesis of well‐defined functional block copolymers. The modification reaction proceeds smoothly and yields quantitatively functionalized block copolymers (¹H NMR and FT‐IR spectroscopy) without disturbing the molecular‐weight distribution of the parent copolymer (PDI < 1.09, size exclusion chromatography).

The modular synthetic pathway towards the functional block copolymers reported here.     

Investigation of the use of density functionals in second‐ and third‐row transition metal dimer calculations

We explore the use of density functionals in calculating the equilibrium distances, dissociation energies, and harmonic vibrational frequencies of the homonuclear diatomics of the second‐row transition metals, platinum, and gold. The outermost s–d interconfigurational energies (ICEs) and the outermost s and d ionization potentials (IPs) were also calculated for the second‐ and third‐row transition metal atoms. Compared with the first‐row transition metal dimer calculations (J Chem Phys 2000, 112, 545–553), the binding energies calculated using the combination of the Becke 1988 exchange and the one‐parameter progressive correlation (BOP) functional and Becke's three‐parameter hybrid (B3LYP) functional are in better agreement with the experiment. However, the pure BOP functional still gives the deep and narrow dissociation potential wells for the electron configurations containing high‐angular‐momentum open‐shell orbitals. Analysis of the s–d ICEs and the s and d IPs suggests that the overestimation may be due to the insufficient long‐range interaction between the outermost s and d orbitals in the exchange functional. The hybrid B3LYP functional seems to partly solve this problem for many systems by the incorporation of the Hartree–Fock exchange integral. However, this still leads to an erroneous energy gap between the configurations of fairly different spin multiplicity, probably because of the unbalance of exchange and correlation contributions. © 2001 John Wiley & Sons, Inc. J Comput Chem 22: 1995–2009, 2001     

Preparation of polyhedral oligomeric silsesquioxane‐containing block copolymer with well‐controlled stereoregularity

Preparation of functional domains with a spacing of 10 nm is a benchmark set to fabricate next‐generation electronic devices. Organic–inorganic block copolymers form well‐ordered microphase separations with very small domain sizes. The design and preparation of a novel block copolymer consisting of syndiotactic polymethyl methacrylate (st‐PMMA) and polyhedral oligomeric silsesquioxane (POSS)‐functionalized polymethacrylate, designated as st‐PMMA‐b‐PMAPOSS, which can recognize functional molecules, are reported. The st‐PMMA segments form a helical structure and encapsulate C₆₀ in the helical nanocavity, leading to the formation of an inclusion complex. Although the ordering of the domains is not high, C₆₀ domains that are in a quasi‐equilibrium state, with about 10‐nm domain spacings, are generated using st‐PMMA‐b‐PMAPOSS that can recognize functional molecules. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 2181–2189     

End‐functionalization of isotactic polypropylene via consecutive chain transfer reaction to norbornadiene and hydrogen

Structurally well‐defined end functionalized isotactic polypropylene (iPP) is prepared by conducting a selective chain transfer reaction during the isospecific polymerization of propylene in the presence of norbornadiene (NBD) and hydrogen using rac‐Me₂Si(2‐Me‐4‐Ph‐Ind)₂ ZrCl₂/MAO as the catalyst. The production of NBD‐capped iPP involves a unique consecutive chain transfer reaction, first to NBD and then to hydrogen, for situating the incorporated NBD at the iPP chain end. The NBD end group of NBD‐capped iPP can be converted into other reactive functional group through functional group transformation reactions. The resulting functional group end‐capped iPP can be used for the construction of stereoregular block copolymers (e.g., iPP‐b‐PMMA and iPP‐b‐PS) through postpolymeriztion reactions. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Combining Atom Transfer Radical Polymerization and Click Chemistry: A Versatile Method for the Preparation of End‐Functional Polymers

Summary: The bromine chain ends of well‐defined polystyrene ( = 2 700 g · mol⁻¹, = 1.11) prepared using ATRP were successfully transformed into various functional end groups (ω‐hydroxy, ω‐carboxyl and ω‐methyl‐vinyl) by a two‐step pathway: (1) substitution of the bromine terminal atom by an azide function and (2) 1,3‐dipolar cycloaddition of the terminal azide and functional alkynes (propargyl alcohol, propiolic acid and 2‐methyl‐1‐buten‐3‐yne). The “click” cycloaddition was catalyzed efficiently by the system copper bromide/4,4′‐di‐(5‐nonyl)‐2,2′‐bipyridine. In all cases, ¹H NMR spectra indicated quantitative transformation of the chain ends of polystyrene into the desired function.

Preparation of well‐defined functional polymers possessing diverse chain‐end functionalities by the combination of atom transfer radical polymerization and click chemistry.     

Synthesis of phosphate end‐functional polymers and application to thermally latent polymeric initiators

Novel phosphates, O‐p‐(hydroxymethyl)benzyl O,O‐diethyl phosphate ( 1 ) and O‐(2‐bromoisobutyryloxymethyl)benzyl O,O‐diethyl phosphate ( 2 ) were synthesized by the reaction of diethyl phosphorochloridate with 1,4‐benzenedimethanol and the successive reaction with 2‐bromoisobutyryl bromide in the presence of triethylamine and submitted to the polymerization of ?‐caprolactone and methyl methacrylate as the initiators. They afforded phosphate end‐functional poly(?‐caprolactone) and poly(methyl methacrylate) with controlled molecular weights and polydispersity ratios by living ring‐opening polymerization and samarium‐induced polymerization. The polymerization of glycidyl phenyl ether (GPE) was carried out with the phosphate end‐functional polymers as the latent polymeric initiators in the presence of ZnCl₂. The polymerization of GPE did not proceed below 90 °C, but it rapidly proceeded to afford poly(GPE) above the temperature. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3832–3840, 2001     

ABC‐type hetero‐arm star terpolymers through “Click” chemistry

Hetero‐arm star ABC‐type terpolymers, poly(methyl methacrylate)‐polystyrene‐poly(tert‐butyl acrylate) (PMMA‐PS‐PtBA) and PMMA‐PS‐poly(ethylene glycol) (PEG), were prepared by using “Click” chemistry strategy. For this, first, PMMA‐b‐PS with alkyne functional group at the junction point was obtained from successive atom transfer radical polymerization (ATRP) and nitroxide‐mediated radical polymerization (NMP) routes. Furthermore, PtBA obtained from ATRP of tBA and commercially available monohydroxyl PEG were efficiently converted to the azide end‐functionalized polymers. As a second step, the alkyne and azide functional polymers were reacted to give the hetero‐arm star polymers in the presence of CuBr/N,N,N′,N″,N″‐pentamethyldiethylenetriamine ( PMDETA) in DMF at room temperature for 24 h. The hetero‐arm star polymers were characterized by ¹H NMR, GPC, and DSC. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 5699–5707, 2006     

Preparation and Characteristics of Esculin‐Imprinted Polymers

Four molecularly imprinted polymers (MIPs) were prepared in MeOH with esculin (=6,7‐dihydroxycoumarin 6‐(β‐D ‐glucopyranoside)=6‐(β‐D ‐glucopyranosyloxy)‐7‐hydroxy‐2H‐1‐benzopyran‐2‐one) as the imprinted molecule, methacrylic acid (=2‐methylprop‐2‐enoic acid; MAA), acrylamide (=prop‐2‐enamide; AM), 4‐vinylpyridine (=4‐ethenylpyridine; 4‐VP), or 2‐vinylpyridine (=2‐ethenylpyridine; 2‐VP) as the functional monomer, respectively, as well as ethylene glycol dimethacrylate (=2‐methylprop‐2‐enoic acid ethane‐1,2‐diyl ester; EGDMA) as the cross‐linking agent. The interaction between the template and the functional monomers was investigated by fluorescence and UV spectrophotometry, respectively, which revealed the presence of esculin/monomer complexes in the stoichiometric ratio 1 : 2 in the pre‐polymerization mixture. The resultant polymers were studied in equilibrium binding experiments to evaluate the recognition ability and the binding capacity towards esculin. The results showed that MIP₁, prepared with MAA as the functional monomer, exhibited advantageous characteristics of high binding capacity, optimal imprinting effect, and good selectivity towards esculin. The Scatchard analysis indicated that there are two types of binding sites in MIP₁, and its binding parameters including the apparent maximum numbers of binding sites and the dissociation constants were calculated. Finally, by packing an SPE column (SPE=solid‐phase extraction) with MIP₁, the esculin was separated and enriched successfully by this sorbent from samples of Cortex fraxini, and the average recovery was up to 74.7%.     

Synthesis and photovoltaic properties of functional dendritic oligothiophenes

Novel p‐type and low bandgap functional dendritic oligothiophenes bearing hole‐transporting carbazole as peripheral substituents and an electron‐withdrawing dicyanovinyl core group, namely, DCT(n)‐DCN, where n = 1 or 2 for solution‐processable photovoltaic (PV) applications have been synthesized. With electron‐donating carbazole surface‐functionalized moieties conjugated with dicyanovinyl core group, the optical bandgap of these functional dendritic oligothiophene thin‐films greatly reduces to 1.74 eV with a strong spectral broadening and a high ionization potential at ～5.5 eV as determined by UV photoelectron spectroscopy. The bulk heterojunction PV cells fabricated from these dendrimers blended with PC₇₁BM as an acceptor showed a power conversion efficiency up to 1.64% with an open circuit voltage of (V_oc) = 0.93 V in the annealed device. We have demonstrated that the desirable molecular and PV properties of dendritic oligothiophenes can be obtained/tuned by the incorporation of functional group(s) onto peripheral of the dendron and into the core. In addition, these functional dendritic oligothiophenes show superior functional properties even at low dendritic generation as compared to the unsubstituted higher generation dendritic oligothiophenes as a p‐type, low‐bandgap semiconductor for solution‐processable bulk heterojunction PV cells. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Electronic Properties of Two Series of Blue-Emitting Conjugated Oligomers and Polymers Based on Cyanostilbene： A Quantum Chemistry Study

One of the drawbacks of the electroluminescence （EL） polymers is that they are usually much better at accepting and transporting holes than electrons due to their inherent richness of π-electrons. One approach improving electron injection and transport in conjugated polymers is to incorporate moieties with high electron affinities. In this theoretical work, to gain an insight into the chemical structure-property relationships was aimed by controllable modification of the main chain structures. Two cyanovinylene derivatives with 2,7-fluorenylene and p-phenylene moieties in the main chains, namely, poly { （2,5-dimethoxy-p-phenylene- 1,4-ylene）-alt-[ 1,2-bis（p-phenylene）- 1- cyanovinylene]} （PPhCN） and poly{[9,9-dimethyl-2,7-fluorenylene]-alt-[1,2-bis（p-phenylene）-1-cyanovinylene]} （PFCN）, were studied employing density functional theory （DFT） and time dependent density functional theory （TD-DFT） with B3LYP functional. The electronic properties of the neutral molecules, extrapolated ionization potentials （IP） and electron affinities （EA）, and energy gaps were investigated in comparison with pristine poly（2,7- fluorenylene）. From comparison with poly（2,7-fluorenylene） （PF）, the 1,2-bis（p-phenylene）-1-cyanovi-nylene unit was found to be a good electron-withdrawing moiety for electronic materials and the incorporation of 1,2-bis（p- phenylene）-1-cyanovinylene resulted in a narrow band gap and a red shift of both the absorption and photoluminescence emission peaks. Most importantly, the LUMO energies of PFCN are around 1 eV lower than those of PF, which results in the decrement of EA about 0.9 eV, indicating that the 1,2-bis（p-phenylene）-1-cyanovinylene unit has significantly improved the electron-accepting properties of the copolymer PFCN. Substitution of 2,5-dimethoxy-p-phenylene for 9,9-dimethyl-2,7-fluorenylene induced larger band gaps and thus a blue-shift in absorption and emission peaks, which can be attributed to the better conjugated backbone in PFCN.     

Double icosahedron‐based motif of Nin (n = 20−30)

A genetic algorithm (GA) coupled with a tight‐binding (TB) interatomic potential was used to search for the low‐energy structures of the medium‐sized Ni_n (n = 20?30) clusters. The low‐energy candidate structures from the GA/TB search were further optimized by using the density functional theory calculations with the Perdew, Burke, and Ernzerhof exchange‐correlation energy functional. The obtained lowest‐energy structures of the medium‐sized Ni_n (n = 20?30) clusters are shown to exhibit double icosahedron‐based motif. The properties of the nickel clusters including binding energies, second differences in energy, and especially magnetic properties have also been studied. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2012     

Vinyl‐triazolium monomers: Versatile and new class of radically polymerizable ionic monomers

A set of eight functional 4‐vinyl‐1,2,3‐triazolium monomers were synthesized using copper catalyzed azide‐alkyne 2 + 3 Hüisgen cycloaddition. These vinyl‐trizolium monomers readily polymerized via free radical polymerization. The physical properties of the vinyl‐triazolium based poly(ionic liquid)s (PILs) are strongly dependent on the pendant functional groups. These polymers were characterized for glass transition temperature (T_g), solubility, and the thermal decomposition. The vinyl‐triazolium based PILs offer an efficient route to highly functional PILs with the advantage of facile synthesis and the ability to incorporate many desirable functional moieties. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 417–423     

Heteroarm H‐shaped terpolymers through click reaction

Heteroarm H‐shaped terpolymers, (polystyrene)(poly(methyl methacrylate))‐ poly(tert‐butyl acrylate)‐(polystyrene)(poly(methyl methacrylate)), (PS)(PMMA)‐PtBA‐(PMMA)(PS), and, (PS)(PMMA)‐poly(ethylene glycol)(PEG)‐(PMMA)(PS), through click reaction strategy between PS‐PMMA copolymer (as side chains) with an alkyne functional group at the junction point and diazide end‐functionalized PtBA or PEG (as a main chain). PS‐PMMA with alkyne functional group was prepared by sequential living radical polymerizations such as the nitroxide mediated (NMP) and the metal mediated‐living radical polymerization (ATRP) routes. The obtained H‐shaped polymers were characterized by using ¹H‐NMR, GPC, DSC, and AFM measurements. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1055–1065, 2007     

Preparation and Characterization of Trans‐Resveratrol Imprinted Polymers

Abstract

In order to selectively extract trans‐resveratrol from Chinese herbs, molecularly imprinted polymers (MIPs) were prepared with trans‐resveratrol as the template molecule. The influences of porogenic solvents and functional monomers on the recognition properties of the polymer were studied. The MIP, which was prepared in acetone using 4‐vinylpyridine as functional monomer, displayed good affinity and recognition property for the template molecule. This indicates that the 4‐vinylpyridine can form hydrogen‐bonding or ionic interaction with trans‐resveratrol. Experimental result also indicated that the MIP column can separate trans‐resveratrol from matrix components in the Polygonum cuspidatum extract.