Pendant structure governed anion sensing property for sulfonamide‐functionalized poly(phenylacetylene)s bearing various α‐amino acids

The colorimetric detection of anionic species has been studied for α‐amino acid‐conjugated poly(phenylacetylene)s, which were prepared by the polymerization of the ethyl esters of N‐(4‐ethynylphenylsulfonyl)‐L ‐alanine, L ‐isoleucine, L ‐valine, L ‐phenylalanine, L ‐aspartic acid, and L ‐glutamic acid using Rh⁺(2,5‐norbornadiene)[(η⁶‐C₆H₅)B^?(C₆H₅)₃] as the catalyst in CHCl₃. The one‐handed helical conformations of all the sulfonamide‐functionalized polymers were characterized by Cotton effects in the circular dichroism spectra. The addition of anions with a relatively high basicity, such as tetra‐n‐butylammonium acetate and fluoride, induced drastic changes in both the optical and chiroptical properties. On the other hand, anions with a relatively low basicity, such as tetra‐n‐butylammonium nitrate, azide, and bromide, had essentially no effects on the helical conformation of all the sulfonamide‐functionalized polymers. The anion signaling property of the sulfonamide‐functionalized polymers possessing α‐amino acid moieties was significantly affected by the installed residual amino acid structures. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1683–1689, 2010     

Synthesis of End‐Functionalized Polyacetylenes that Contain Polar Groups by Employing Well‐Defined Palladium Catalysts

A series of [(dppf)PdBr(R)]‐type complexes (dppf=1,1′‐bis(diphenylphosphino)ferrocene; R=p‐cyanophenyl ( 1 a ), o‐hydroxymethylphenyl ( 1 b ), and triphenylvinyl ( 1 c )), in combination with silver trifluoromethanesulfonate (AgOTf), were demonstrated to be active for the polymerization of monosubstituted polar acetylene monomers HC?CCONHC₄H₉ ( 2 ), HC?CCO₂C₈H₁₇ ( 3 ), HC?CCH₂OCONHC₆H₁₃ ( 4 ), HC?CCH₂OCO₂C₆H₁₃ ( 5 ), and HC?CCH(CH₃)OH ( 6 ). The yields and molecular weights of the polymers depended on the combination of the Pd catalyst and monomer that was employed. Matrix‐assisted laser‐desorption/ionization–time of flight (MALDI‐TOF) mass spectrometric analysis indicated the formation of polymers that contained the “R” and “H” groups at the chain ends. IR spectroscopic analysis supported the R‐end‐functionalization of the polymers. NMR spectroscopy and MS identified the presence of species that were formed by single, double, and triple insertion of the monomers into the Pd‐C₆H₄‐p‐CN bond, thereby giving solid evidence for an insertion mechanism for the present system. Density functional theory (DFT) calculations suggested the preference for 1,2‐insertion of the monomer compared to 2,1‐insertion.     

Ring‐opening polymerization of cyclic esters promoted by phosphido‐diphosphine pincer group 3 complexes

Phosphido‐diphosphine Group 3 metal complexes 1–4 [(o‐C₆H₄PR₂)₂P‐M(CH₂SiMe₃)₂; R = Ph, 1 : M = Y, 2 : M = Sc; R = iPr, 3 : M = Y, 4 : M = Sc] are very efficient catalysts for the ring‐opening polymerization (ROP) of cyclic esters such as ε‐caprolactone (ε‐CL), L ‐lactide, and δ‐valerolactone under mild polymerization conditions. In the ROP of ε‐CL, complexes 1–4 promote quantitative conversion of high amount of monomer (up to 3000 equiv) with very high turnover frequencies (TOF) (～4 × 10⁴ mol_CL/mol_I h) showing a catalytic activity among the highest reported in the literature. The immortal and living ROP of ε‐CL and L ‐lactide is feasible by combining complexes 1–4 with 5 equiv of 2‐propanol. Polymers with controlled molecular parameters (M_n, end groups) and low polydispersities (M_w/M_n = 1.05–1.09) are formed as a result of fast alkoxide/alcohol exchange. In the ROP of δ‐valerolactone, complexes 1–4 showed the same activity observed for lactide (L ‐ and D ,L ‐lactide) producing high molecular weight polymers with narrow distribution of molar masses. Complexes 1–4 also promote the ROP of rac‐β butyrolactone affording atactic low molecular weight poly(hydroxybutyrate) bearing unsaturated end groups probably generated by elimination reactions. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Recyclable helical poly(phenylacetylene)‐supported catalyst for asymmetric aldol reaction in aqueous media

A novel one‐handed helical poly(phenylacetylene) bearing L‐hydroxyproline pendants (poly(PA‐P)) was synthesized as an eco‐friendly polymer‐supported catalyst for asymmetric reactions. The helical poly(PA‐P) catalyzed the asymmetric aldol reactions of cyclohexanone with p‐nitrobenzaldehyde, and showed good recyclability and higher enantiomeric excess (ee) in aqueous medias than that in organic medias. The one‐handed helicity of poly(PA‐P) was clearly affected by the water content in the aqueous media. The helical poly(PA‐P) showed the higher enantioselectivity (ee = 99%) than its monomer PA‐P (ee = 54%) in THF/H₂O (H₂O vol % = 25.0 vol %). After the one‐handed helical structure of poly(PA‐P) was destroyed by grinding treatment, the ee of the reaction clearly decreased from 99 to 49%. These indicate that the one‐handed helical structure of poly(PA‐P) played an important role in the high enantioselectivity of the asymmetric aldol reactions in the aqueous media. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 1024–1031     

Synthesis of well‐defined and end‐polymerizable star‐shaped polysulfides and their application to negative photoresist

Various star‐shaped poly(phenoxy propylene sulfide)s (PPSs) bearing curable end groups were synthesized by the functionalization of the propagating ends of star‐shaped poly(PPS) with various electrophilies. The functionalization with chloromethyl styrene proceeded quantitatively, and afforded polymers with M_n almost agreed with theoretical value and narrow M_w/M_n. The photocuring conditions were optimized, and the addition of 10 wt % of poly(ethylene glycol) diacrylate was effective to attain sufficient crosslinking. The photocuring reaction of the end‐functionalized poly(PPS) films cast on silicon wafers was conducted by UV irradiation. The cured poly (PPS)s became insoluble in THF, supporting the sufficient crosslinking. Developing of a cured polymer yielded a negative photoresist pattern. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

Synthesis of porphyrin‐end‐functionalized polycyclohexane with well‐controlled and defined polymer chain structure

Tetraphenylporphyrin‐end‐functionalized polycyclohexane (H₂TPP‐PCHE) and its metal complexes (MTPP‐PCHE) were synthesized as the first successful example of porphyrin‐end‐functionalized transparent and stable polymers with a well‐controlled and defined polymer chain structure. Chloromethyl‐end‐functionalized poly(1,3‐cyclohexadiene) (CM‐PCHD) was synthesized as prerequisite prepolymer by the postpolymerization reaction of poly(1,3‐cyclohexadienyl)lithium and chloro(chloromethyl)dimethylsilane. CM‐end‐functionalized PCHE (CM‐PCHE) was prepared by the complete hydrogenation of CM‐PCHD with p‐toluenesulfonyl hydrazide. H₂TPP was incorporated onto the polymer chain end by the addition of 5‐(4‐hydroxyphenyl)‐10,15,20‐triphenylporphyrin to CM‐PCHE. The complexation of H₂TPP‐PCHE and Zn(OAc)₂ (or PtCl₂) yielded a zinc (or platinum) complex of H₂TPP‐PCHE. H₂TPP‐PCHE and MTPP‐PCHE were readily soluble in common organic solvents, and PCHE did not inhibit the optical properties of the H₂TPP, ZnTPP, and PtTPP end groups. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Synthesis of poly(1‐chloro‐2‐arylacetylene)s with high cis‐content and examination of their absorption/emission properties

A series of 1‐chloro‐2‐arylacetylenes [Cl‐C?C‐Ar, Ar = C₆H₅ ( 1 ), C₆H₄‐p‐i Pr ( 2 ), C₆H₄‐p‐Oi Pr ( 3 ), C₆H₄‐p‐NHC(O)Ot Bu ( 4 ), and C₆H₄‐o‐i Pr ( 5 )] were polymerized using (tBu₃P)PdMeCl/silver trifluoromethanesulfonate (AgOTf) and MoCl₅/SnBu₄ catalysts. The corresponding polymers [poly( 1 )–poly( 5 )] with weight‐average molecular weights of 6,500–690,000 were obtained in 10–91% yields. THF‐insoluble parts, presumably high‐molecular weight polymers, were formed together with THF‐soluble polymers by the Pd‐catalyzed polymerization. The Pd catalyst polymerized nonpolar monomers 1 and 2 to give the polymers in yields lower than the Mo catalyst, while the Pd catalyst polymerized polar monomers 3 and 4 to give the corresponding polymers in higher yields. The ¹H NMR and UV–vis absorption spectra of the polymers indicated that the cis‐contents of the Pd‐based polymers were higher than those of the Mo‐based polymers, and the conjugation length of the Pd‐based polymers was shorter than that of the Mo‐based polymers. Pd‐based poly( 5 ) emitted fluorescence most strongly among poly( 1 )–poly( 5 ). © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55 , 382–388     

Synthesis of regioregular poly(3‐octylthiophene)s via Suzuki polycondensation and end‐group analysis by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry

Regioregular poly(3‐octylthiophene)s were synthesized through a palladium‐catalyzed Suzuki polycondensation of 2‐(5‐iodo‐4‐octyl‐2‐thienyl)‐4,4,5,5‐tetramethyl‐1,3,2‐dioxaborolane. The effects of the palladium catalyst {tetrakis(triphenylphosphine)palladium(0) [Pd(PPh₃)₄], palladium(II) acetate [Pd(OAc)₂], [1, 1′‐bis(diphenylphosphino)ferrocene]dichloropalladium(II) [Pd(dppf)Cl₂], tris(dibenzylideneacetone)dipalladium(0), or bis(triphenylphosphine)palladium(II) dichloride [Pd(PPh₃)₂Cl₂]} and the reaction conditions (bases and solvents) were investigated. NMR spectroscopy revealed that poly(3‐octylthiophene)s prepared via this route were essentially regioregular. According to size exclusion chromatography, the highest molecular weights were obtained with in situ generated Pd(PPh₃)₄ and tetrakis(tri‐o‐tolylphosphine]palladium(0) {Pd[P(o‐Tol)₃]₄} catalysts or more reactive, phosphine‐free Pd(OAc)₂. Matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry was used to analyze end groups and allowed the determination of some mechanistic aspects of the Suzuki polycondensation. The polymers were commonly terminated with hydrogen or iodine as a result of deboronation and some deiodination. Pd(PPh₃)₄, Pd(PPh₃)₂Cl₂, and Pd[P(o‐Tol)₃]₄ induced aryl–aryl exchange reactions with the palladium center and resulted in some chains having phenyl‐ and o‐tolyl‐capped chain ends. Pd(dppf)Cl₂ yielded only one type of chain, and it had hydrogen end groups. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1454–1462, 2005     

Association of hydrophobically α,ω‐end‐capped poly(2‐methyl‐2‐oxazoline) in water

The α,ω‐end‐capped poly(2‐methyl‐2‐oxazoline) (C_n‐POXZ‐C_n) have been synthesized by a one‐pot process using cationic ring‐opening polymerization with an appropriate initiator and terminating agent. The polymers bearing different alkyl groups C₁₂ and C₁₈ have molecular weight in the range of 2.4 × 10³ to 14 × 10³ with a small polydispersity index. The solution behavior of the free chains has been analyzed in a nonselective solvent, dichloromethane, by small‐angle neutron scattering and dynamic light scattering. These amphiphilic polymers associate in water to form flower‐like micellar structures. Critical micelle concentrations, investigated by fluorescence technique, are in the range of 0.03–0.5 g L^?1 and are dependent on the hydrophilic/lipophilic balance. The structural properties of the aggregates have also been investigated by viscometry. Intrinsic viscosities of these polymers are in the same range as that of the precursors poly(2‐methyl‐2‐oxazoline) (POXZ) and mono‐functionalized polymers. Large viscosity increase corresponding to intermicellar bridging was observed in the vicinity of the micelle overlap concentration. Addition of hydroxypropyl β‐cyclodextrin (HβCD) has dissociated the aggregates and the intrinsic viscosities of the HβCD‐end‐capped chains have become comparable with the ones of POXZ precursor chains. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2477–2485, 2010     

Synthesis and polymerization of phenylacetylene having two carbazole units and properties of the formed polymer

Novel carbazole‐containing acetylene monomer, 1‐(3‐ethynyl‐9‐carbazoyl)?4‐(9‐carbazoyl)benzene 1 was synthesized, polymerized, and copolymerized with phenylacetylene ( PA ) using [(nbd)RhCl]₂‐Et₃N, Rh⁺(nbd)[η⁶‐C₆H₅B^–(C₆H₅)₃], and WCl₆‐Ph₄Sn as catalysts. Polymers with number‐average molecular weights ranging from 7800 to 33,200 were obtained in 60%–quantitative yields. The absorption band edge of poly( 1 ‐co‐ PA ) ( 1 :PA = 8:2) was positioned at a wavelength longer than those of 1 and polyvinylcarbazole. Poly( 1 ‐co‐ PA ) ( 1:PA = 8:2) emitted fluorescence with 60% quantum yield. Poly( 1 ‐co‐ PA ) ( 1:PA = 8:2) worked as a hole transport material of an OLED with tris(8‐hydroxyquinoline)aluminum (Alq3) as an emission material. © 2015 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 2015 , 53, 1245–1251     

Micron‐granula polyolefin with self‐immobilized nickel and iron diimine catalysts bearing one or two allyl groups

Self‐immobilized nickel and iron diimine catalysts bearing one or two allyl groups of [ArN?C]₂(C₁₀H₆)NiBr₂ [Ar = 4‐allyl‐2,6‐(i‐Pr)₂C₆H₂] ( 1 ), [ArN?C(Me)][Ar′N? C(Me)]C₅H₃NFeCl₂ [Ar = Ar′ = 4‐allyl‐2,6‐(i‐Pr)₂C₆H₃, Ar = 2,6‐(i‐Pr)₂C₆H₃, and Ar′ = 4‐allyl‐2,6‐(i‐Pr)₂C₆H₃] were synthesized and characterized. All three catalysts were investigated for olefin polymerization. As a result, these catalysts not only showed high activities as the catalyst free from the allyl group, such as [ArN?C]₂C₁₀H₆NiBr₂ (Ar = 2,6‐(i‐Pr)₂C₆H₂)], but also greatly improved the morphology of polymer particles to afford micron‐granula polyolefin. The self‐immobilization of catalysts, the formation mechanism of microspherical polymer, and the influence on the size of the particles are discussed. The molecular structure of self‐immobilized nickel catalyst 1 was also characterized by crystallographic analysis. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 1018–1024, 2004     

Living regioselective copolymerization of ethylene with nonconjugated bicyclic dienes using (salicylaldiminato)(β‐enaminoketonato) titanium catalysts

A series of heteroligated (salicylaldiminato)(β‐enaminoketonato)titanium complexes [3‐^tBu‐2‐OC₆H₃CH?N(C₆F₅)] [PhN?C(CF₃)CHCRO]TiCl₂ [ 3a : R = Ph, 3b : R = C₆H₄Cl(p), 3c : R = C₆H₄OMe(p), 3d : R = C₆H₄Me(p), 3e : R = C₆H₄Me(o)] were synthesized and characterized. Molecular structures of 3b and 3c were further confirmed by X‐ray crystallographic analyses. In the presence of modified methylaluminoxane as a cocatalyst, these unsymmetric catalysts displayed favorable ability to incorporate 5‐vinyl‐2‐norbornene (VNB) and 5‐ethylidene‐2‐norbornene (ENB) into the polymer chains, affording high‐molecular weight copolymers with high‐comonomer incorporations and alternating sequence under the mild conditions. The comonomer concentration in the polymerization medium had a profound influence on the molecular weight distribution of the resultant copolymer. At initial comonomer concentration of higher than 0.4 mol/L, the titanium complexes with electron‐donating groups in the β‐enaminoketonato moiety mediated room‐temperature living ethylene/VNB or ENB copolymerizations. Polymerization results coupled with density functional theory calculations suggested that the highly controlled living copolymerization is probably a consequence of the difficulty in chain transfer of VNB (or ENB)‐last‐inserted species and some characteristics of living ethylene polymerization under limited conditions. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Polymerization of substituted phenylacetylenes with a novel,water‐soluble Rh–vinyl complex in water

A novel, water‐soluble Rh complex, (nbd)Rh[PPh₂(m‐NaOSO₂C₆H₄)] [C(Ph)?CPh₂] ( 1 ) was synthesized by the reaction of [(nbd)RhCl]₂, Ph₂P(m‐NaOSO₂C₆H₄) and Ph₂C?C(Ph)Li, whose structure was determined by NMR and IR spectroscopies. The Rh catalyst 1 induced the polymerization of phenylacetylene (PA) in water to give two kinds of polymers; one was soluble in organic solvents such as tetrahydrofuran (THF) and CHCl₃, and the other was insoluble in common organic solvents. The polymerization of sodium p‐ethynylbenzoate (p‐NaOCO‐PA) homogeneously proceeded with 1 in water at 60 °C to give the polymer in high yield. Poly(p‐NaOCO‐PA) was treated with 1 N HCl and then reacted with (CH₃)₃SiCHN₂ to obtain poly(p‐MeOCO‐PA). The methyl‐esterified polymer was insoluble in THF and CHCl₃, which suggests that the formed poly(p‐MeOCO‐PA) has cis–cisoidal structure. The polymer obtained from the polymerization of [p‐CH₃(OCH₂CH₂)₂O₂CC₆H₄]C?CH with 1 in water was soluble in methanol, ethanol, and THF, and partly soluble in water. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2100–2105, 2004     

Synthesis and bifunctional asymmetric organocatalysis of helical poly(phenylacetylene)s bearing cinchona alkaloid pendants via a sulfonamide linkage

Four novel helical poly(phenylacetylene)s with amino‐functionalized cinchona alkaloid pendant groups connecting to the phenyl rings through a sulfonamide linkage were synthesized by the polymerization of the corresponding phenylacetylene monomers using Rh⁺(2,5‐norbornadiene)[(η⁶‐C₆H₅)B^?(C₆H₅)₃] (Rh(nbd)BPh₄) as the catalyst. The optically active sulfonamide‐linked polymers adopted a helical conformation with an excess of one‐handedness as supported by the appearance of the induced Cotton effects in the main‐chain chromophore regions, and efficiently catalyzed the enantioselective methanolytic desymmetrization of a cyclic anhydride and aza‐Michael addition of aniline to chalcone, thereby producing the corresponding optically active products up to 86% enantiomeric excess. However, their enantioselectivities from the methanolytic desymmetrization were slightly lower than those catalyzed by the corresponding cinchona alkaloid‐bound monomers. On the other hand, during the asymmetric aza‐Michael addition, a unique enhancement of the enantioselectivity was observed for several sulfonamide‐linked helical polymers, and thus affording a remarkably higher enantioselectivity compared to those of the corresponding monomers and nonhelical polymers bearing the identical cinchona alkaloid residues. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 2869–2879     

Synthesis of brush‐shaped polymers consisting of a poly(phenylacetylene) backbone and pendant poly(vinyl ether)s via selective reaction of 2‐Vinyloxyethyl 4‐Ethynylbenzoate

We have newly designed an original bifunctional monomer (PAVE) containing both a phenylacetylene (PA) group and a vinyl ether (VE) group, which is expected to be a key material for the synthesis of brush‐shaped polymers consisting of a poly(phenylacetylene) (polyPA) main chain and polyVE side chains. Actually, we have demonstrated the selective chemical transformation of the VE moiety of PAVE to an initiator site for the living cationic polymerization of isobutyl vinyl ether (IBVE), and then succeeded in the controlled synthesis of a novel PA‐end‐capped polyIBVE macromonomer. Moreover, using this macromonomer, the first synthesis of a brush‐shaped polyPA bearing polyVE side chains was achieved via Rh complex‐mediated homopolymerization. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 2800–2805     

Luminescent mesogen jacketed poly(1‐alkyne) bearing lateral terphenyl with hexyloxy tail

Mesogen jacketed liquid crystalline poly(1‐alkyne) and poly(1‐phenyl‐1‐alkyne) linked pendants of terphenyl mesogens with hexyloxy tails at the waist position (? {RC?C? [(CH₂)₃OOC‐terpheyl‐(OC₆H₁₃)₂]}_n? , where R?H, PHATP(OC6)2 ; R?C₆H₅, PPATP(OC6)2 ) were synthesized. The influences of structural variations on the thermal, mesomorphic, and luminescent properties were investigated. Polymerizations of all monomers are carried out by WCl₆‐Ph₄Sn catalysts successfully. The polymers are stable (T_d ≥ 340 °C) and soluble in common solvents. The monomers and polymers show enantiotropic SmA phases in the heating and cooling processes, and the lateral side chains of the mesogenic units are perpendicular to the main chain. The “jacket effect” of chromophoric terphenyl core “shell” around the main chain also contributes to polymers with high photoluminescence, and the pendant‐to‐backbone energy transfer path is involved in the luminescence process of this polymers. In comparison with monosubstituted polyacetylene PHATP(OC6)2 , the disubstituted polyacetylene PPATP(OC6)2 shows better photoluminescence in both THF solution and film, and exhibited about 40 nm red‐shifted than PHATP(OC6)2 , indicating that the “jacket effect” of terphenyl mesogens forces poly(1‐phenyl‐1‐alkyne) backbone to extend in a more planar conformation with a better conjugation. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

Heterograft copolymers via double click reactions using one‐pot technique

The double click reactions (Cu catalyzed Huisgen and Diels–Alder reactions) were used as a new strategy for the preparation of well‐defined heterograft copolymers in one‐pot technique. The synthetic strategy to the various stages of this work is outlined: (i) preparing random copolymers of styrene (St) and p‐chloromethylstyrene (CMS) (which is a functionalizable monomer) via nitroxide mediated radical polymerization (NMP); (ii) attachment of anthracene functionality to the preformed copolymer by the o‐etherification procedure and then conversion of the remaining ? CH₂Cl into azide functionality; (iii) by using double click reactions in one‐pot technique, maleimide end‐functionalized poly(methyl methacrylate) (PMMA‐MI) via atom transfer radical polymerization (ATRP) of MMA and alkyne end‐functionalized poly (ethylene glycol) (PEG‐alkyne) were introduced onto the copolymer bearing pendant anthryl and azide moieties. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6969–6977, 2008     

Synthesis and chiroptical properties of L‐valine‐containing poly(phenylacetylene)s with (a)chiral pendant terminal groups

Poly(phenylacetylene)s containing L ‐valine residues (P 1 ) with (a)chiral pendant terminal groups R^(*) [?(HC?C{C₆H₄CONHCH[CH(CH₃)₂]COO? R^(*)})_n?]; R^(*) = 1‐octyl (P 1 o), (1S,2R,5S)‐(+)‐menthyl [P 1 (+)], (1R,2S,5R)‐(?)‐menthyl [P 1 (?)] are designed and synthesized. The polymers are prepared by organorhodium catalysts in high yields (yield up to 88%) with high molecular weights (M_w up to ?6.4 × 10⁵). Their structures and properties are characterized by NMR, IR, TGA, UV, and circular dichroism analyses. All the polymers are thermally fairly stable (T_d ≥ 320 °C). The chiral moieties induce the poly(phenylacetylene) chains to helically rotate in a preferred direction. The chirality of the pendant terminal groups affects little the helicity of the polymers but their bulkiness stabilizes the helical conformation against solvent perturbation. The backbone conjugation and chain helicity of the polymers can be modulated continuously and reversibly by acid. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 2117–2129, 2006     

Pd(II) complexes of Schiff bases and their application as catalysts in Mizoroki–Heck and Suzuki–Miyaura cross‐coupling reactions

Schiff bases of 2‐(phenylthio)aniline, (C₆H₅)SC₆H₄N?CR (R = (o‐CH₃)(C₆H₅), (o‐OCH₃)(C₆H₅) or (o‐CF₃)(C₆H₅)), and their palladium complexes (PdLCl₂) were synthesized. The compounds were characterized using ¹H NMR and ¹³C NMR spectroscopy and micro analysis. Also, electrochemical properties of the ligands and Pd(II) complexes were investigated in dimethylformamide–LiClO₄ solution with cyclic and square wave voltammetry techniques. The Pd(II) complexes showed both reversible and quasi‐reversible processes in the ?1.5 to 0.3 V potential range. The synthesized Pd(II) complexes were evaluated as catalysts in Mizoroki–Heck and Suzuki–Miyaura cross‐coupling reactions. Copyright © 2015 John Wiley & Sons, Ltd.     

Synthesis and properties of carbamate‐ and amine‐containing poly(phenylacetylenes)

The 3‐ and 4‐aminophenylacetylenes protected by t‐butoxycarbonyl (t‐Boc) and 9‐fluorenylmethoxycarbonyl (Fmoc) groups ( 3a – 6a ) were synthesized and polymerized using [(nbd)RhCl]₂ ( 1 ) and [(nbd)Rh⁺‐η⁶‐PhB^?Ph₃] ( 2 ) catalysts. The t‐Boc‐containing polymers [poly( 3a ) and poly( 4a )] were obtained in high yield (82–91%). Among the Fmoc‐protected monomers, the para‐derivative polymerized well [poly( 6a ); yield = 85–94%], whereas its meta‐substituted analogue did not afford high molecular weight polymer in good yield [poly( 5a ); yield = 10–15%]. The use of KN(SiMe₃)₂ as a cocatalyst in conjunction with 1 led to a dramatic increase in the molecular weight of the polymers. The acid‐ and base‐catalyzed removal of the t‐Boc and the Fmoc groups, respectively, generated primary amine‐containing polymers [poly( 3b )–poly( 6b )] which cannot be obtained directly by the polymerization of the corresponding monomers. The solubility characteristics of the polymers bearing protected amino groups were quite different from those of the unprotected ones, the former being soluble in polar solvents, whereas the latter displayed poor solubility even in polar protic or highly polar aprotic solvents. The attempts to accomplish the free‐standing membrane fabrication by solution casting were successful only for poly( 3a ), and an augmentation in the gas permeability and CO₂/N₂ permselectivity was discerned in comparison with the unsubstituted poly(phenylacetylene) and poly(m‐t‐butyldimethylsiloxyphenylacetylene). © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1853–1863, 2009