Synthesis and characterization of new aromatic polyamides bearing crown ethers or their dipodal counterparts in the pendant structure. II. Benzo‐15‐crown‐5 and ortho‐bis[2‐(2‐ethoxyethoxy)ethoxy]benzene

This article describes the synthesis and characterization of two diacid monomers, each containing a benzo‐15‐crown‐5 subunit or its dipodal counterpart. Both novel monomers were reacted with technical aromatic diamines with Yamazaki's direct polyamidation method to render modified polyisophthalamides with high molecular weights containing side moieties of cyclic and acyclic ethylene oxide sequences. All the polymers were soluble in aprotic polar solvents and showed high glass‐transition temperatures in the range of 190–345 °C. The polymers with side crown ethers showed much higher glass‐transition temperatures than those with acyclic linear side ethylene oxide arms. The chemical composition, particularly with respect to the diamine and the open or closed character of the pendent ethylene oxide sequence, also affected other general properties such as the mechanical resistance, mechanical modulus, or water absorption. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 4063–4075, 2006     

Synthesis and characterization of new aromatic polyamides bearing crown ethers and acyclic ethylene oxide units in the pendant structure. III. Benzo‐18‐crown‐6 systems and their open‐chain counterparts

We report the synthesis and characterization of 10 novel polyamides containing the benzo‐18‐crown‐6 subunit and its dipodal counterpart, along with their properties, and a comparison with homologous polyamides bearing benzo‐12‐crown‐4, benzo‐15‐crown‐5, and the corresponding dipodal systems. The anomalous polymerization of some of the diacid monomers, that leads to insoluble gels under standard Yamazaki polymerization conditions, is described. The gel formation has been attributed to the threading of cyclic oligoamides with a growing polyamide chain to yield rotaxanes, polyrotaxanes, catenanes, or polycatenanes. Polyamide macrocycles have been characterized with matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry. A route to avoid gel formation, consisting of a lower initial monomer concentration, is also described, along with the polymer properties of the polyamides obtained, including the chemical characterization, mechanical behavior, water sorption, morphology, diffusion data, and permeability of membranes prepared with these polymers. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6252–6269, 2006     

Synthesis and characterization of new soluble aromatic polyamides based on 4‐(1‐adamantyl)‐1, 3‐bis(4‐aminophenoxy)benzene

A set of new aromatic polyamides were synthesized by the direct phosphorylation condensation of 4‐(1‐adamantyl)‐1,3‐bis‐(4‐aminophenoxy)benzene with various diacids. The polymers were produced with high yields and moderate to high inherent viscosities (0.43–1.03 dL/g), and the weight‐average molecular weights and number‐average molecular weights, determined by gel permeation chromatography, were in the range of 37,000–93,000 and 12,000–59,000, respectively. The polyamides were essentially amorphous and soluble in a variety of solvents such as N,N‐dimethylacetamide (DMAc), cyclohexanone, and tetrahydrofuran. They showed glass‐transition temperatures in the range of 240–300 °C (differential scanning calorimetry) and 10% weight‐loss temperatures over 450 °C, as revealed by thermogravimetric analysis in nitrogen. All the polymers gave strong films via casting from DMAc solutions, and these films exhibited good mechanical properties, with tensile strengths in the range of 77–92 MPa and tensile moduli between 1.5 and 2.5 GPa. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 1014–1023, 2000     

Synthesis and characterization of aromatic polymers containing pendant silyl groups. II. Aromatic polyamides

In order to improve the solubility of aromatic polyamides without significant loss of thermal stability, synthesis of aromatic polyamides containing pendant silyl groups was carried out by direct polycondensation of silylated aromatic diacids such as 2-trimethylsilylterephthalic acid (TSTA), 2,5-bis (trimethylsilyl) terephthalic acid (BTSTA), 5-trimethylsilylisophthalic acid (TSIA), 5-dimethylphenylsilylisophthalic acid (DMSIA), and 5-triphenylsilylisophthalic acid (TPSIA) with various aromatic diamines. The resulting polyamides had inherent viscosities in the range of 0.18–1.10 dL/g and showed improved solubilities toward aprotic polar solvents such as NMP, DMF, DMSO, etc. The prepared aromatic polyamides exhibited fairly good thermal stabilities, which were almost comparable to those of corresponding nonsubstituted aromatic polyamides. That is, thermogravimetric analysis (TGA) data revealed 10% weight losses at 358–500°C and residual weights at 700°C were 46–67% under nitrogen atmosphere. © 1992 John Wiley & Sons, Inc.     

Synthesis and characterization of new soluble aromatic polyamides derived from 1,4‐Bis(4‐carboxyphenoxy)‐2, 5‐di‐tert‐butylbenzene

Aromatic polyamides based on a novel bis(ether‐carboxylic acid) were synthesized by the direct phosphorylation condensation method. 1,4‐Bis(4‐carboxyphenoxy)‐2,5‐di‐tert‐butylbenzene was combined with various diamines containing flexible linkages and side substituents to render a set of eight novel aromatic polyamides. The polymers were produced with high yields and moderate to high inherent viscosities (0.49–1.32 dL/g) that corresponded to weight‐average and number‐average molecular weights (by gel permeation chromatography) of 31,000–80,000 and 19,000–50,000, respectively. Except for a single example, the polyamides were essentially amorphous and soluble in a variety of common solvents such as cyclohexanone, dioxane, and tetrahydrofuran. They showed glass‐transition temperatures of 250–295 °C (by differential scanning calorimetry) and 10% weight loss temperatures above 460 °C, as revealed by thermogravimetric analysis in nitrogen. Polymer films, obtained by casting from N,N‐dimethylacetamide solutions, exhibited good mechanical properties, with tensile strengths of 83–111 MPa and tensile moduli of 2.0–2.2 GPa. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 475–485, 2001     

Synthesis and characterization of novel soluble triphenylamine‐containing aromatic polyamides based on N,N′‐bis(4‐aminophenyl)‐N,N′‐diphenyl‐1,4‐phenylenediamine

A new triphenylamine‐containing aromatic diamine, N, N′‐bis(4‐aminophenyl)‐N, N′‐diphenyl‐1,4‐phenylenediamine, was prepared by the condensation of N,N′‐diphenyl‐1,4‐phenylenediamine with 4‐fluoronitrobenzene, followed by catalytic reduction. A series of novel aromatic polyamides with triphenylamine units were prepared from the diamine and various aromatic dicarboxylic acids or their diacid chlorides via the direct phosphorylation polycondensation or low‐temperature solution polycondensation. All the polyamides were amorphous and readily soluble in many organic solvents such as N, N‐dimethylacetamide and N‐methyl‐2‐pyrrolidone. These polymers could be solution cast into transparent, tough, and flexible films with good mechanical properties. They had useful levels of thermal stability associated with relatively high glass‐transition temperatures (257–287 °C), 10% weight‐loss temperatures in excess of 550 °C, and char yields at 800 °C in nitrogen higher than 72%. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2810–2818, 2002     

Preparation and characterization of aromatic polyamides based on a bis(ether‐carboxylic acid) or a dietheramine extended from 1,1‐bis(4‐hydroxyphenyl)‐1‐phenylethane

Thermoplastic and organic‐soluble aromatic polyamides containing both bulky triphenylethane units and flexible ether linkages were prepared directly from 1,1‐bis[4‐(4‐carboxyphenoxy)phenyl]‐1‐phenylethane ( III ) with various aromatic diamines or from 1,1‐bis[4‐(4‐aminophenoxy)phenyl]‐1‐phenylethane ( V ) with various aromatic dicarboxylic diacids via triphenyl phosphite and pyridine. These polyamides had inherent viscosities ranging from 0.71 to 1.77 dL/g. All the polymers easily were dissolved in aprotic polar solvents such as N‐methyl‐2‐pyrrolidone and N,N‐dimethylacetamide, and some even could be dissolved in less polar solvents such as tetrahydrofuran. The flexible and tough films cast from the polymer solutions possessed tensile strengths of 89 to 104 MPa. The polyamides were thermally stable up to 460°C in air or nitrogen. Glass‐transition temperatures of these polyamides were observed in a range of 179 to 268°C via differential scanning calorimetry or thermomechanical analysis. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 247–260, 2000     

Synthesis and properties of soluble aromatic polyamides derived from 2,2′‐bis(4‐carboxyphenoxy)‐9,9′‐spirobifluorene

The synthesis of a new bis(ether carboxylic acid), 2,2′‐bis(4‐carboxyphenoxy)‐9,9′‐spirobifluorene, in which two orthogonally arranged carboxyphenoxyfluorene entities are connected through an sp³ carbon atom (the spiro center), is reported. The direct phosphorylation polycondensation of this diacid monomer with various aromatic diamines yields aromatic polyamides containing 9,9′‐spirobifluorene moieties in the main chain. The presence of the spiro segment restricts the close packing of the polymer chains and decreases interchain interactions, resulting in amorphous polyamides with enhanced solubility, and high glass‐transition temperatures and good thermal stability are maintained through controlled segmental mobility. The glass‐transition temperatures of these polyamides are in the range of 234–306 °C, with 10% weight losses occurring at temperatures above 530 °C. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1160–1166, 2003     

Synthesis,characterization, and ion‐complexing properties of polymers displaying densely packed arrays of crown‐ethers as lateral substituents

We report the synthesis and ion‐binding properties of four poly(crown‐ethers) displaying either one or two crown‐ethers (15‐crown‐5 or 18‐crown‐6) on every third carbon alongside the backbone. The polymers were synthesized by living anionic ring‐opening polymerization of disubstituted cyclopropane‐1,1‐dicarboxylates monomers. Cation binding of the polychelating polymers and corresponding monomers to Na⁺ and K⁺ was evaluated by picrate extraction and isothermal calorimetry titration. This novel family of poly(crown‐ethers) demonstrated excellent initial binding of the alkali ions to the polymers, with a higher selectivity for potassium. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 2337–2345     

Synthesis and characterization of new organosoluble polyamides derived from bis[4‐(4‐carboxyphenoxy) phenyl]diphenylmethane

A new dicarboxylic acid containing a diphenylmethylene linkage, bis[4‐(4‐carboxyphenoxy)phenyl]diphenylmethane (BCAPD), was prepared from bis(4‐hydroxphenyl)diphenylmethane and p‐fluorobenzonitrile via an aromatic nucleophilic substitution reaction followed by hydrolysis. A series of novel polyamides were prepared by the direct polycondensation of BCAPD and various aromatic diamines. The polymers were produced with moderate to high inherent viscosities of 0.80–0.85 dL g^?1. Nearly all the polymers were readily soluble in polar solvents such as N‐methyl‐2‐pyrrolidinone, N,N‐dimethylacetamide, N,N‐dimethylformamide, and dimethyl sulfoxide, in less polar solvents such as pyridine and cyclohexanone, and in tetrahydrofuran. All the polymers were amorphous, and the polyamide films had a tensile strength and a tensile modulus greater than 80 MPa and 2.0 GPa, respectively. These polyamides had glass‐transition temperatures between 249 and 274 °C, and their temperatures at a 10% weight loss were 477–538 and 483–540 °C in nitrogen and air atmospheres, respectively. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1156–1161, 2001     

Fluorinated polyamides and poly(amide imide)s based on 1,4‐bis(4‐amino‐2‐trifluromethylphenoxy)benzene,aromatic dicarboxylic acids,and various monotrimellitimides and bistrimellitimides: Syntheses and properties

A CF₃‐containing diamine, 1,4‐bis(4‐amino‐2‐trifluromethylphenoxy) benzene ( I ), was prepared from hydroquinone and 2‐chloro‐5‐nitrobenzotrifluoride. Imide‐containing diacids ( V _a–h and VI _a,b ) were prepared through the condensation reaction of amino acids, aromatic diamines, and trimellitic anhydride. Then, a series of soluble fluorinated polyamides ( VII _a–h ) and poly(amide imide)s ( VIII _a–h and X _a,b ) were synthesized from I with various aromatic diacids ( II _a–h ) and imide‐containing diacids ( V _a–h and VI _a,b ) via direct polycondensation with triphenyl phosphate and pyridine. The polyamides and poly(amide imide)s had inherent viscosities of 1.00–1.70 and 0.79–1.34 dL/g, respectively. All the synthesized polymers showed excellent solubility in amide‐type solvents such as N‐methyl‐2‐pyrrolidinone, N,N‐dimethylacetamide, and N‐dimethylformamide and afforded transparent and tough films via solvent casting. Polymer films of VII _a–h , VIII _a–h , and X _a,b had tensile strengths of 91–113 MPa, elongations to break of 8–40%, and initial moduli of 2.1–2.8 GPa. The glass‐transition temperatures of the polyamides and poly(amide imide)s were 254–276 and 255–292 °C, respectively, and the imide‐containing poly(amide imide)s had better thermal stability than the polyamides. The polyamides showed higher transparency and were much lighter in color than the poly(amide imide)s, and their cutoff wave numbers were below 400 nm. In comparison with isomeric IX _{c – h} , poly(amide imide)s VIII _c–h exhibited less coloring and showed lower yellowness indices. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3116–3129, 2004     

Synthesis and properties of new soluble aromatic polyamides and polyimides on the basis of N,N′‐bis(3‐aminobenzoyl)‐N,N′‐diphenyl‐1,4‐phenylenediamine

A new N‐phenylated amide (N‐phenylamide) unit containing aromatic diamine, N,N′‐bis(3‐aminobenzoyl)‐N,N′‐diphenyl‐1,4‐phenylenediamine, was prepared by the condensation of N,N′‐diphenyl‐1,4‐phenylenediamine with 3‐nitrobenzoyl chloride, followed by catalytic reduction. Two series of organosoluble aromatic poly(N‐phenylamide‐imide)s and poly(N‐phenylamide‐amide)s with inherent viscosities of 0.58–0.82 and 0.56–1.21 dL/g were prepared by a conventional two‐stage method and the direct phosphorylation polycondensation, respectively, from the diamine with various aromatic dianhydrides and aromatic dicarboxylic acids. All polyimides and polyamides are amorphous and readily soluble in many organic solvents such as N,N‐dimethylacetamide and N‐methyl‐2‐pyrrolidone. These polymers could be solution cast into transparent, tough, and flexible films with high tensile strengths. These polyimides and polyamides had glass‐transition temperatures in the ranges of 230–258 and 196–229 °C, respectively. Decomposition temperatures of the polyimides for 10% weight loss all occurred above 500 °C in both nitrogen and air atmospheres. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2564–2574, 2002     

Synthesis and evaluation of photoluminescent and electrochemical properties of new aromatic polyamides and polyimides with a kink 1,2‐phenylenediamine moiety

A series of novel triphenylamine‐containing aromatic polyamides and polyimides having a crank and twisted noncoplanar structures were synthesized in inherent viscosities of 0.14–0.64 dL/g and 0.11–0.67 dL/g, respectively. These polymers had useful levels of thermal stability associated with relatively high glass‐transition temperatures (174–311 °C). They exhibited strong UV–Vis absorption bands at around 300 nm in NMP solutions. The PL spectra of these polymers in NMP solutions (1 × 10^?5 M) showed maximum peaks around 396–479 nm. The hole‐transporting and electrochromic properties were examined by electrochemical and spectroelectrochemical methods. Cyclic voltammetry (CV) of the polymer films cast onto an indium‐tin oxide (ITO)‐coated glass substrate exhibited two reversible oxidation redox couples at potentials of 0.70–1.01 V and 1.10–1.46 V, respectively, vs. Ag/AgCl in acetonitrile solution. The polymer films revealed electrochromic characteristics, with a color change from neutral pale yellowish to green and then to a blue oxidized form at applied potentials ranging from 0.00 to 1.75 V. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 2587–2603, 2006     

Synthesis and characterization of fluorinated poly(amide imide)s derived from 1,4‐bis(2′‐trifluoromethyl‐4′‐trimellitimidophenoxy)benzene and aromatic diamines

A series of fluorinated poly(amide imide)s were prepared from 1,4‐bis(2′‐trifluoromethyl‐4′‐trimellitimidophenoxy)benzene and various aromatic diamines [3,3′,5,5′‐tetramethyl‐4,4′‐diaminediphenylmethane, α,α‐bis(4‐amino‐3,5‐dimethyl phenyl)‐3′‐trifluoromethylphenylmethane, 1,4‐bis(4′‐amino‐2′‐trifluoromethylphenoxy)benzene, 4‐(3′‐trifluoromethylphenyl)‐2,6‐bis(3′‐aminophenyl)pyridine, and 1,1‐bis(4′‐aminophenyl)‐1‐(3′‐trifluoromethylphenyl)‐2,2,2‐trifluoroethane]. The fluorinated poly(amide imide)s, prepared by a one‐step polycondensation procedure, had good solubility both in strong aprotic solvents, such as N‐methyl‐2‐pyrrolidinone, dimethylacetamide, dimethylformamide, dimethyl sulfoxide, and cyclopentanone, and in common organic solvents, such as tetrahydrofuran and m‐cresol. Strong and flexible polymer films with tensile strengths of 84–99 MPa and ultimate elongation values of 6–9% were prepared by the casting of polymer solutions onto glass substrates, followed by thermal baking. The poly(amide imide) films exhibited high thermal stability, with glass‐transition temperatures of 257–266 °C and initial thermal decomposition temperatures of greater than 540 °C. The polymer films also had good dielectric properties, with dielectric constants of 3.26–3.52 and dissipation factors of 3.0–7.7 × 10^?3, and acceptable electrical insulating properties. The balance of excellent solubility and thermal stability associated with good mechanical and electrical properties made the poly(amide imide)s potential candidates for practical applications in the microelectronics industry and other related fields. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1831–1840, 2003     

Preparation and characterization of fluorine‐containing aromatic condensation polymers. VII. Aromatic polyacetals and copolyacetals from 2,2‐bis(4‐hydroxyphenyl)‐1,1,1,3,3,3‐hexafluoropropane and/or 2,2‐bis(4‐hydroxyphenyl)propane and 2‐(trifluoromethyl)benzal chloride

A series of fluorine‐containing aromatic homopolyacetals and copolyacetals with a wide range of unit ratios were synthesized by the solution polycondensation of 2,2‐bis(4‐hydroxyphenyl)‐1,1,1,3,3,3‐hexafluoropropane (bisphenol AF), 2,2‐bis(4‐hydroxyphenyl)propane (bisphenol A), or both with 2‐(trifluoromethyl)benzal chloride, and the effect of fluorine substitution on the properties of these polymers is discussed in relation to the fluorine contents. High molecular weight polyacetals with reduced viscosities of 0.43–0.97 dL/g were obtained in high yields with potassium hydroxide as a base, 18‐crown 6‐ether as a catalyst, and N‐methyl‐2‐pyrrolidinone as a medium at 100 °C for 3 h. Regardless of the fluorine contents, these polymers all were highly soluble in various solvents, including benzene, chloroform, ethyl acetate, and tetrahydrofuran, and afforded colorless, transparent, and tough films by solution casting. The temperatures of 5% weight loss and 10% weight loss under nitrogen both increased significantly and monotonously with increasing fluorine content, whereas the glass‐transition temperatures were scarcely affected by fluorine substitution. The dielectric constant at 1 MHz of the bisphenol AF‐based homopolyacetal was 2.43, which was remarkably lower than the value of the bisphenol A‐based homopolyacetal, 2.68. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 1873–1879, 2000     

Synthesis and characterization of crown ether–containing N‐phosphorylated thioureas RC(S)NHP(O)(OiPr)2 (R = 1‐aza‐15‐crown‐5, 1‐aza‐12‐crown‐4) and their Co(II) and Ni(II) complexes

The reaction of the lithium salts of N‐phosphorylated thioureas RC(S)NHP(O)(OiPr)₂ (R = 1‐aza‐15‐crown‐5, HL ^I ; 1‐aza‐12‐crown‐4, HL ^II ) with Co(II) or Ni(II) leads to the chelate complexes [ ML ^I,II ₂ ]. The metal center is found in a tetrahedral ([ CoL ^I,II ₂ ]) or square planar ([ NiL ^I,II ₂ ]) O₂S₂ environment formed by the CS sulfur atoms and the PO oxygen atoms of two deprotonated ligands L . The molecular structure of [ CoL ^I ₂ ] was elucidated by X‐ray diffraction and the extraction properties of HL ^I,II and [ ML ^I,II ₂ ] toward alkali metal and ammonium picrates were investigated. © 2010 Wiley Periodicals, Inc. Heteroatom Chem 21:486–491, 2010; View this article online at wileyonlinelibrary.com . DOI 10.1002/hc.20637     

Synthesis and properties of new aromatic polysquaramide by solid‐state thermal polycondensation of salt monomer composed of squaric acid and bis(4‐aminophenyl) ether

The 1:1 stoichiometric salt monomer composed of squaric acid and bis(4‐aminophenyl) ether was successfully prepared and subjected to solid‐state thermal polycondensation under ordinary or high pressure, giving quite readily the aromatic polysquaramide with moderately high molecular weight. The polysquaramide formed was actually the random copolymer consisting of two component polymers, one of the main component being the polymer with a quasi‐aromatic mesoionic structure. The aromatic polysquaramide was crystalline and had a glass‐transition temperature of 245 °C, with an initial weight‐loss temperature of 400 °C in nitrogen. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2648–2655, 2002     

Synthesis and structural characterization of iridium(I) complexes of 20‐membered macrocyclic rings bearing chelating bis(N‐heterocyclic carbene) ligands

The reactivities of two 20‐membered macrocyclic ligands, each containing two N‐heterocyclic carbene (NHC) and two amine groups, towards [IrCl(COD)]₂ (COD is cycloocta‐1,5‐diene) were investigated. Macrocycles containing imidazolin‐2‐ylidene groups formed the monometallic complex [(1,2,5,6‐η)‐cycloocta‐1,5‐diene](5,16‐dibenzyl‐1,5,9,12,16,20‐hexaazatricyclo[18.2.1.1^9,12]tetracosa‐10,21‐dien‐21,22‐diylidene)iridium(I) bromide dichloromethane monosolvate, [Ir(C₈H₁₂)(C₃₂H₄₂N₆)]Br·CH₂Cl₂, 2a . The structure of iridium complex 2a at 100 K has triclinic P symmetry. The ligand in 2a coordinates to the Ir center through the NHC moieties in a cis fashion. Additionally, the ligand adopts an umbrella‐like structure that appears to envelope the Ir center. The structure displays C—H…Br interactions. Macrocycles containing benzimidazolin‐2‐ylidene groups formed the bimetallic complex [μ‐5,20‐dibenzyl‐1,5,9,16,20,24‐hexaazapentacyclo[22.6.1.1^9,16.0^10,15.0^25,30]dotriaconta‐10(15),11,13,25(30),26,28‐hexaene‐31,32‐diylidene]bis{bromido[(1,2,5,6‐η)‐cycloocta‐1,5‐diene]iridium(I)}, [Ir₂Br₂(C₈H₁₂)₂(C₄₀H₄₆N₆)], 2b . The structure of complex 2b at 100 K has orthorhombic Pbca symmetry. Each NHC moiety in 2b coordinates in a monodentate fashion to an Ir(COD) fragment. The structure exhibits disorder of the main molecule. This disorder is found in the portion of the macrocycle containing an amine group. This structure also displays C—H…Br interactions. Finally, the structure of the hexafluorophosphate salt of the imidazolin‐2‐ylidene‐containing macrocycle, namely 5,16‐dibenzyl‐1λ⁵,5,9,12λ⁵,16,20‐hexaazatricyclo[18.2.1.1^9,12]tetracosa‐1(23),10,12(24),21‐tetraene‐1,12‐diium bis(hexafluorophosphate), C₃₂H₄₄N₆²⁺·2PF₆^?, 1c , was determined. The structure of macrocycle 1c at 100 K has triclinic P symmetry and was found to contain C—H…F interactions.     

Radical copolymerization of 2‐trifluoromethylacrylic monomers. I. Kinetics of their copolymerization with norbornenes and vinyl ethers as studied by in situ 1H NMR analysis

Radical copolymerizations of electron‐deficient 2‐trifluoromethylacrylic (TFMA) monomers and electron‐rich norbornene derivatives and vinyl ethers with azobisisobutyronitrile were investigated by analyzing the kinetics in situ with ¹H NMR. Although none of the monomers underwent radical homopolymerization under normal conditions, they copolymerized readily, producing a copolymer containing 60–70 mol % TFMA. Terpolymerization involving these monomers was also investigated. The rates of copolymerization and kinetic chain lengths were determined in some cases on the basis of the in situ kinetics analysis. These radial copolymerizations of TFMA provide a basis for the preparation of chemical‐amplification resist polymers for emerging 157‐nm lithography. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 1468–1477, 2004