Synthesis and characterization of new soluble and thermally stable poly(ester-imide)s derived from N-[3,5-bis(N-trimellitoyl)phenyl]phthalimide and various bisphenols

A new dicarboxylic acid chloride (2) bearing three preformed imide rings was synthesized by treating N-(3,5-diaminophenyl)phthalimide with trimellitic anhydride followed by refluxing with thionyl chloride. A novel family of aromatic poly(ester-imide)s with inherent viscosities of 0.27-0.35 dl g⁻¹ were prepared from 2 with various bisphenols such as resorcinol (3a), hydroquinone (3b), 2,2′-dihydroxybiphenyl (3c), 4,4′-dihydroxybiphenyl (3d), bisphenol-A (3e), 2,2′-dimethyl-4,4′-dihydroxybiphenyl (3f), 1,5-dihydroxynaphthalene (3g), 2,7-dihydroxynaphthalene (3h), and 2,2′-dihydroxy-1,1′-binaphthyl (3i) by high-temperature solution polycondensation in nitrobenzene using pyridine as hydrogen chloride quencher. All of the resulted polymers were fully characterized by FT-IR and NMR spectroscopy and elemental analyses. The poly(ester-imide)s exhibited excellent solubility in some polar organic solvents. From differential scanning calorimetry, the polymers showed glass-transition temperatures between 259 and 353 °C. Thermal behaviors of the obtained polymers were characterized by thermogravimetric analysis and the 10% weight loss temperatures of the poly(ester-imide)s were found to be in the range between 451 and 482 °C in nitrogen. Furthermore, crystallinity of the polymers was estimated by means of wide-angle X-ray diffraction.     

Rapid synthesis of optically active poly(amide-imide)s by direct polycondensation of aromatic dicarboxylic acid with aromatic diamines

4,4^′-(Hexafluoroisopropylidene)-N,N^′-bis(phthaloyl-l-leucine-p-amidobenzoic acid) (2) was prepared from the reaction of 4,4^′-(hexafluoroisopropylidene)-N,N^′-bis(phthaloyl-l-leucine) diacid chloride with p-aminobenzoic acid. The direct polycondensation reaction of monomer (2) with p-phenylenediamine (2a), 4,4^′-diaminodiphenylsulfone (2b), 2,4-diaminotoluene (2c), 2,6-diaminopyridine (2d), m-phenylene diamine (2e), benzidine (2f), 4,4^′-diaminodiphenylether (2g) and 4,4^′-diaminodiphenyl methane (2h) was carried out in a medium consisting of triphenyl phosphite, N-methyl-2-pyrolidone, pyridine, and calcium chloride. The homogeneous mixture was heated at 220 °C for 1 min under nitrogen. The resulting poly(amide-imide)s (PAIs) having inherent viscosities 0.27-0.78 dl/g were obtained in high yield and are optically active and thermally stable. All of the above polymers were fully characterized by IR spectroscopy, elemental analyses and specific rotation. Some structural characterization and physical properties of this new optically active PAIs are reported.     

Novel organosoluble and colorless poly(ether imide)s based on 1,1-bis[4-(3,4-dicarboxyphenoxy)phenyl]cyclohexane dianhydride and trifluoromethyl-substituted aromatic bis(ether amine)s

A series of novel fluorinated poly(ether imide)s (IV) having inherent viscosities of 0.70-1.08 dL/g were prepared from 1,1-bis[4-(3,4-dicarboxyphenoxy)phenyl]cyclohexane dianhydride (I) and various trifluoromethyl (CF₃)-substituted aromatic bis(ether amine)s II_a-g by a standard two-step process with thermal and chemical imidization of poly(amic acid) precursors. These poly(ether imide)s showed excellent solubility in many organic solvents and could be solution-cast into transparent, flexible, and tough films. These films were essentially colorless, with an ultraviolet-visible absorption edge of 375-380 nm and a very low b^∗ value (a yellowness index) of 5.5-7.3. They also showed good thermal stability with glass-transition temperatures of 207-269 °C, 10% weight loss temperatures in excess of 474 °C, and char yields at 800 °C in nitrogen more than 62%. In comparison with analogous V series poly(ether imide)s without the -CF₃ substituents, the IV series polymers showed better solubility, lower color intensity, and lower dielectric constants.     

Microwave-promoted synthesis of new optically active poly(ester-imide)s derived from N,N-(pyromellitoyl)-bis-l-leucine diacid chloride and aromatic diols

Pyromellitic dianhydride (benzene-1,2,4,5-tetracarboxylic dianhydride) (1) was reacted with l-leucine (2) in a mixture of acetic acid and pyridine (3:2) and the resulting imide-acid [N,N^′-(pyromellitoyl)-bis-l-leucine diacid] (4) was obtained in quantitative yield. The compound (4) was converted to the N,N^′-(pyromellitoyl)-bis-l-leucine diacid chloride (5) by reaction with thionyl chloride. A new facile and rapid polycondensation reaction of this diacid chloride (5) with several aromatic diols such as phenol phthalein (6a), bisphenol-A (6b), 4,4^′-hydroquinone (6c), 1,8-dihydroxyanthraquinone (6d), 1,5-dihydroxy naphthalene (6e), 4,4-dihydroxy biphenyl (6f), and 2,4-dihydroxyacetophenone (6g) was developed by using a domestic microwave oven in the presence of a small amount of a polar organic medium such as o-cresol. The polymerization reactions proceeded rapidly and are completed within 10 min, producing a series of optically active poly(ester-imide)s (PEIs) with good yield and moderate inherent viscosity of 0.10-0.27 dl/g. All of the above polymers were fully characterized by IR, elemental analyses and specific rotation. Some structural characterization and physical properties of these optically active PEIs are reported.     

Novel optically active poly(amide-imide)s from N,N-(4,4-carbonyldiphthaloyl)-bis-l-phenylalanine diacid chloride and aromatic diamines by microwave irradiation

3,3^′,4,4^′-benzophenonetetracarboxylic dianhydride (4,4^′-carbonyldiphthalic anhydride) (1) was reacted with l-phenylalanine (2) in a mixture of acetic acid and pyridine (3:2) and the resulting imide-acid [N,N^′-(4,4^′-carbonyldiphthaloyl)-bis-l-phenylalanine diacid] (4) was obtained in high yield. The compound (4) was converted to the N,N^′-(4,4^′-carbonyldiphthaloyl)-bis-l-phenylalanine diacid chloride (5) by reaction with thionyl chloride. A new facile and rapid polycondensation reaction of this diacid chloride (5) with several aromatic diamines such as 4,4^′-diaminodiphenyl methane (6a), 2,4-diaminotoluene (6b), 4,4^′-sulfonyldianiline (6c), p-phenylenediamine (6d), 4,4^′-diaminodiphenylether (6e), m-phenylenediamine (6f), benzidine (6g) and 2,6-diaminopyridine (6h) was developed by using a domestic microwave oven in the presence of a small amount of a polar organic medium such as o-cresol. The polymerization reactions proceeded rapidly, compared with the conventional solution polycondensation, and was completed within 7 min, producing a series of optically active poly(amide-imide)s with high yield and inherent viscosity of 0.22-0.52 dl/g. All of the above polymers were fully characterized by IR, elemental analyses and specific rotation. Some structural characterization and physical properties of this optically active poly(amide-imide)s are reported.     

Synthesis and properties of novel aromatic poly(ester-imide)s bearing 1,5-bis(benzoyloxy)naphthalene units

Two series of new aromatic poly(ester-imide)s were prepared from 1,5-bis(4-aminobenzoyloxy)naphthalene (p-1) and 1,5-bis(3-aminobenzoyloxy)naphthalene (m-1), respectively, with six commercially available aromatic tetracarboxylic dianhydrides via a conventional two-stage synthesis that included ring-opening polyaddition to give poly(amic acid)s followed by chemical imidization to polyimides. The intermediate poly(amic acid)s obtained in the first stage had inherent viscosities of 0.41-0.84 and 0.66-1.37 dl/g, respectively. All the para-series and most of the meta-series poly(ester-imide)s were semicrystalline and showed less solubility. Two of the meta-series poly(ester-imide)s derived from less rigid dianhydrides were amorphous and readily soluble in polar aprotic solvents, and they could be solution-cast into transparent and tough films with good mechanical properties. The meta-series polymers derived from rigid dianhydrides were generally semicrystalline and showed less solubility. Except for one example, the meta-series poly(ester-imide)s displayed discernible T_gs in the range 239-273 °C by DSC. All of these two series poly(ester-imide)s did not show significant decomposition below 450 °C in nitrogen or in air.     

Synthesis, photoluminescent and electrochromic properties of new aromatic poly(amine-hydrazide)s and poly(amine-1,3,4-oxadiazole)s derived from 4,4′-dicarboxy-4″-methyltriphenylamine

A series of new poly(amine-hydrazide)s I were prepared from the dicarboxylic acid 4,4′-dicarboxy-4″-methyltriphenylamine with terephthalic dihydrazide (TPH) and isophthalic dihydrazide (IPH), respectively, via the Yamazaki phosphorylation reaction. Polymers I were readily soluble in many common organic solvents, and could be solution cast into transparent, tough, and flexible films with good mechanical properties. Differential scanning calorimetry (DSC) indicated that the hydrazide polymers had T_g’s in the range of 222-223 °C and could be thermally cyclodehydrated into the corresponding oxadiazole polymers in the range of 300-400 °C. The resulting poly(amine-1,3,4-oxadiazole)s II exhibited T_g’s in the range of 269-283 °C, 10% weight-loss temperatures in excess of 511 °C, and char yield at 800 °C in nitrogen higher than 63%. These poly(amine-hydrazide)s I exhibited strong UV-Vis absorption bands at 351-355 nm in NMP solution. Their photoluminescence spectra in NMP solution and film showed maximum bands around 459-461 nm in the blue region for I series. The hole-transporting and electrochromic properties are examined by electrochemical and spectroelectrochemical methods. Cyclic voltammograms of the poly(amine-hydrazide)s I prepared by casting polymer solution onto an indium-tin oxide (ITO)-coated glass substrate exhibited one reversible oxidation redox couples at 1.32-1.33 V vs. Ag/AgCl in acetonitrile solution. All obtained poly(amine-hydrazide)s I revealed excellent stability of electrochromic characteristics, changing color from original pale yellowish to blue.     

Regularly alternating poly(amideimide)s containing pendent pentadecyl chains: Synthesis and characterization

Two new aromatic diamines containing preformed amide linkages, viz., N,N′-(4-pentadecyl-1,3-phenylene)bis(4-aminobenzamide) I and N,N′-(4-pentadecyl-1,3-phenylene)bis(3-aminobenzamide) II, were synthesized by reaction of 4-pentadecylbenzene-1,3-diamine with 4-nitrobenzoylchloride and 3-nitrobenzoylchloride, followed by reduction of the respective dinitro derivatives. A series of new poly(amideimide)s was synthesized by polycondensation of I and II with four commercially available aromatic dianhydrides, viz., pyromellitic dianhydride (PMDA), 4,4′-biphenyltetracarboxylic dianhydride (BPDA), 4,4′-oxydiphthalic anhydride (ODPA), and 4,4′-(hexafluoroisopropylidene)diphthalic anhydride (6-FDA) in N,N-dimethylacetamide (DMAc) employing conventional two step method via poly(amic acid) intermediate followed by thermal imidization. Reference poly(amideimide)s were synthesized by polycondensation of N,N′-(1,3-phenylene)bis(4-aminobenzamide) and N,N′-(1,3-phenylene)bis(3-aminobenzamide) with the same aromatic dianhydrides. Inherent viscosities of poly(amideimide)s containing pendent pentadecyl chains were in the range 0.37-1.23 dL/g in N,N-dimethylacetamide at 30 ± 0.1 °C indicating the formation of medium to high molecular weight polymers. The poly(amideimide)s containing pendent pentadecyl chains were found to be soluble in N,N-dimethylacetamide, N,N-dimethylformamide, 1-methyl-2-pyrrolidinone and pyridine and could be cast into transparent, flexible and tough films from their N,N-dimethylacetamide solution. Wide angle X-ray diffraction patterns exhibited broad halo indicating that the polymers were essentially amorphous in nature. X-ray diffractograms also displayed sharp reflection in the small angle region (2θ ≈ 3°) for poly(amideimide)s containing pentadecyl chains indicating the formation of layered structure arising from packing of flexible pentadecyl chains. The glass transition temperatures observed for reference poly(amideimide)s were in the range 331-275 °C and those for poly(amideimide)s containing pendent pentadecyl chains were in the range 185-286 °C indicating a large drop in T_g owing to the “internal plasticization” effect of pentadecyl chains. The temperature at 10% weight loss (T₁₀), determined by TGA in nitrogen atmosphere, were in the range 460-480 °C indicating their good thermal stability.     

Synthesis and characterization of novel optically active poly(amide-imide)s via direct amidation

N,N′-Pyromelliticdiimido-di-l-methionine (3) was prepared from the reaction of pyromellitic dianhydride (1) with l-methionine (2) in glacial acetic acid and pyridine solution at refluxing temperature. The direct polycondensation reaction of the monomer diimide-diacid (3) with 1,3-phenylenediamine (4a), 1,4-phenylenediamine (4b), 2,6-diaminopyridine (4c), 3,5-diaminopyridine (4d), 4,4′-diaminodiphenylether (4e) and 4,4′-diaminodiphenylsulfone (4f) was carried out in a medium consisting of triphenyl phosphate, N-methyl-2-pyrolidone, pyridine and calcium chloride. The resulting poly(amide-imide)s having inherent viscosities 0.45-0.53 dl g⁻¹ were obtained in high yields and are optically active and thermally stable. All of the above compounds were fully characterized by IR spectroscopy, elemental analyses and specific rotation. Some structural characterization and physical properties of these new optically active poly(amide-imide)s are reported.     

Synthesis and properties of soluble and light-colored poly(amide-imide-imide)s based on tetraimide-dicarboxylic acid (TIDA) and various aromatic diamines: TIDA from 4,4′-oxydiphthalic anhydride, 1,4-bis(4-amino-2-trifluoromethylphenoxy)benzene, and 3-aminobenzoic acid

A new tetraimide-dicarboxylic acid (TIDA) I was synthesized starting from 3-aminobenzoic acid (m-ABA), 4,4′-oxydiphthalic anhydride (ODPA), and 1,4-bis(4-amino-2-trifluoromethylphenoxy)benzene (BAFPB) at a 2:2:1 molar ratio in N-methyl-2-pyrrolidone (NMP). A series of organosoluble, light-colored poly(amide-imide-imide)s (PAII, III_a-j) was prepared by triphenyl phosphite-activated polycondensation from the tetraimide-diacid I with various aromatic diamines (II_a-j). All the polymers were readily soluble in a variety of organic solvents such as NMP, N,N-dimethyl acetamide (DMAc), dimethyl sulfoxide, and even in less polar m-cresol and pyridine. Polymer films cast from DMAc had the cutoff wavelengths between 374 and 384 nm and had the b^∗ values in the range of 14.8-30.2. Polymers III_a-j afforded tough, transparent, and flexible films, which had tensile strengths ranging from 87 to 103 MPa, elongations at break from 11% to 37%, and initial moduli from 1.9 to 2.3 GPa. The glass transition temperatures of these polymers were in the range of 242-274 °C. They had 10% weight loss temperature above 526 °C and showed the char yield more than 55% residue at 800 °C in nitrogen.     

A new class of aromatic poly(ether-ketone benzoxazole) copolymers by nucleophilic polycondensation: Synthesis and properties

A number of difluorophenyl benzoxazole (DB) monomers and 4,4′-difluorobenzophenone (DFB) were subjected to fluoro-displacement with two different phenoxides in a polar aprotic solvent. A series of novel poly(ether-ketone benzoxazole) copolymers (PAEKBOs) were more readily prepared, in which the generation of aryl-ether linkages was the copolymer forming reaction. The effects of monomer structure and polymerization conditions on the polymerization results and polymer solubility were analyzed. Copolymers 1, 2-X, 4 and 6 were obtained with high molecular weight. Copolymers 2-X and 4 showed organic solubility, especially the copolymers 2-X could dissolve in many usual organic solvents at the solid concentration of up to 20 wt%. TGA and DSC measurements confirmed that the copolymers 2-X, 4 and 6 were thermally stable up to 500 °C, and showed single enhanced T_gs and an amorphous morphology. The copolymers behaved in many respects as engineering thermoplastics. The properties and the processability of several members of the PAEKBOs offer the prospect of being candidates to substitute poly(ether-ether-ketone) (PEEK) using in a wider usage temperature range and being high performance materials for many applications as films, coatings for optical and electronic devices and gas separation membranes.     

Preparation,characterization and thermal degradation study of poly(amide imide)s based on tri-component mixture of PMDA/BTDA,diamines and acid chloride

A series of poly(amide imide)s (PAIs) having alternate (amide–amide) and (imide–imide) units (polymers 1–14 and 22–35), and random distribution of amide-imide linkages (polymers 15–21 and 36–42) were prepared by low temperature solution polymerization of benzene-1,2,4,5-tetracarboxylic dianhydride (PMDA)/benzophenone-3,3′,4,4′-tetracarboxylic dianhydride (BTDA), diamines (cyclic and aromatic) and acid chloride in dimethylforamide. All the polymers were readily soluble in polar aprotic solvents with inherent viscosities in the range of 0.134–0.878. The process of cycloimidization of poly(amide amic acid)s (PAAs) to PAIs was investigated by TGA and FT-IR techniques at four different temperatures i.e., 175, 200, 225, and 260 °C. The rate of cycloimidization was calculated by taking into account the theoretical weight loss (W_T), obtained from [n × M_w (H₂O)/M_w (R_U)] W, where M_w (H₂O) molecular weight of water, W weight of PAA taken for TGA, M_w (R_U) the molecular weight of repeat unit of PAA, n number of water molecules eliminated per repeat unit of PAA upon cycloimidization. For a particular diamine, the extent of percentage cycloimidization at the end of the isothermal heating was higher for PAAs containing trimellitic anhydride chloride (TMAc) unit, irrespective of the nature of the dianhydride and diamine. Thermal and thermooxidative degradation of PAIs was investigated by TGA in nitrogen and oxygen atmosphere. The initial decomposition temperatures (IDT) of polymers are above 260 °C, and vary widely (from 260 to 501 °C) depending upon the structure of the polymer backbone. PAIs containing TMAc exhibited higher thermal stability as compared to those polymers having diacid chloride units, in both N₂/O₂ atmospheres.     

Synthesis and characterization of electrochromic poly(amide-imide)s based on the diimide-diacid from 4,4′-diamino-4″-methoxytriphenylamine and trimellitic anhydride

A dicarboxylic acid bearing two preformed imide rings, namely 4,4′-bis(trimellitimido)-4″-methoxytriphenylamine (3), was prepared by the condensation of 4,4′-diamino-4″-methoxytriphenylamine (2) and two molar equivalents of trimellitic anhydride (TMA). A new family of aromatic poly(amide-imide)s (PAIs) containing the electroactive triphenylamine (TPA) unit were prepared by the triphenyl phosphite activated polycondensation of the diimide-diacid 3 with various aromatic diamines. All the polymers were readily soluble in many organic solvents and could be solution-cast into tough and flexible polymer films. They displayed high glass-transition temperatures (269-313 °C) and good thermal stability, with 10% weight-loss temperatures in excess of 521 °C in nitrogen and char yields at 800 °C in nitrogen higher than 68%. Cyclic voltammograms of the PAI films cast onto an indium-tin oxide (ITO)-coated glass substrate exhibited one reversible oxidation redox couple at 0.91-0.93 V vs. Ag/AgCl in acetonitrile solution. The polymer films revealed a good electrochemical and electrochromic stability, with a color change from colorless neutral form to blue oxidized form at applied potentials ranging from 0.0 to 1.2 V. The PAIs containing the TPA unit in both imide and amide segments showed multicolor electrochromism: pale yellow in the neutral state, green in the semi-oxidized state, and deep blue in the fully oxidized state.     

Novel thermally stable and chiral poly(amide-imide)s bearing from N,N′-(4,4′-diphthaloyl)-bis-l-isoleucine diacid: Synthesis and characterization

Novel optically active aromatic poly(amide-imide)s (PAIs) were prepared from newly synthesized N,N′-(4,4′-diphthaloyl)-bis-l-isoleucine diacid (3) via polycondensation with various diamines. The diacid was synthesized by the condensation reaction of 3,3′,4,4′-biphenyltetracarboxylic dianhydride (1) with l-isoleucine (2) in a mixture of acetic acid and pyridine (3:2 v/v). All the polymers were obtained in quantitative yields with inherent viscosities of 0.20-0.43 dL g⁻¹. All the polymers were highly organosoluble in solvents like N-methyl-2-pyrrolidinone (NMP), N,N-dimethylacetamide (DMAc), N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), tetrahydrofuran, γ-butyrolactone, cyclohexanone and chloroform at room temperature or upon heating. These poly(amide-imide)s had glass transition temperatures between 198 and 231 °C, and their 10% weight-loss temperatures were ranging from 368 to 398 °C and 353 to 375 °C under nitrogen and air, respectively. The polyimide films had tensile strengths in the range of 63-88 MPa and tensile moduli in the range of 0.8-1.4 GPa. These poly(amide-imide)s possessed chiral properties and the specific rotations were in the range of −3.10° to −72.92°.     

Bismuth(III) bis(trifluoromethanesulfonyl)amide

Bismuth(III) bis(trifluoromethanesulfonyl)amide (Bi(NTf₂)₃, 3) has been prepared from the reaction of protiodemetallation of tri-p-tolylbismuth by a stoichiometric amount of bis(trifluoromethanesulfonyl)amine (1). The intermediates BiPh_3−n(NTf₂)_n (n=2 (4), 1 (5)) resulting from the reaction of 1 with triphenylbismuth have also been isolated. The amide 3 was able to catalyze the benzoylation and the benzenesulfonylation of toluene.     

Diisocyanate route as a convenient method for the preparation of novel optically active poly(amide-imide)s based on N-trimellitylimido-S-valine

A new class of optically active poly(amide-imide)s based on an α-amino acid was synthesized via direct polycondensation reaction of different diisocyanates with a chiral diacid monomer. The step-growth polymerization reactions of N-trimellitylimido-S-valine (TISV) (1) with 4,4′-methylene-bis(4-phenylisocyanate) (MDI) (2) was performed under microwave irradiation, as well as solution polymerization under graduate heating and reflux conditions. The optimized polymerization conditions for each method were performed with tolylene-2,4-diisocyanate (TDI) (3), hexamethylene diisocyanate (HDI) (4), and isophorone diisocyanate (IPDI) (5) to produce optically active poly(amide-imide)s via diisocyanate route. The resulting polymers have inherent viscosities in the range of 0.02-1.10 dL/g. Decomposition temperatures for 5% weight loss (T₅) occurred above 300 °C (by TGA) in nitrogen atmospheres. These polymers are optically active, thermally stable and soluble in amide-type solvents. Some structural characterization and physical properties of this new optically active poly(amide-imide)s are reported.     

Soluble and thermally stable polyamides bearing 1,1′-thiobis(2-naphthoxy) groups

A new-type of sulfide containing diacid (1,1′-thiobis(2-naphthoxy acetic acid)) was synthesized from 2-naphthol in three steps. Reaction of 2-naphthol with sulfur dichloride afforded 1,1′-thiobis(2-naphthol) (TBN). 1,1′-Thiobis(2-naphthoxy acetic ester) (TBNAE) was successfully synthesized by refluxing the TBN with methylcholoroacetate in the presence of potassium carbonate. The related diacid was synthesized by basic solution reduction of TBNAE. The obtained diacid was fully characterized and used to prepare novel thermally stable poly(sulfide ether amide)s via polyphosphorylation reaction with different aromatic diamines. The properties of these new polyamides were investigated and compared with similar polyamides. These polyamides showed inherent viscosities in the range of 0.39-0.87 dL g⁻¹ in N,N-dimethylacetamide (DMAc) at 30 °C and at a concentration of 0.5 g dL⁻¹. All the polyamides were readily soluble in a variety of polar solvents such as DMAc and tetrahydrofuran (THF). These polyamides showed glass transition temperature (T_g) between 241-268 °C. Thermogravimetric analysis measurement revealed the decomposition temperature at 10% weight loss (T₁₀) ranging from 441- 479 °C in argon atmosphere.     

A planar silacyclobutane, 1,1-(rac-1,1′-bi-2-naphthoxy)-1-silacyclobutane and its unusual reaction with bis(1,5-cyclooctadiene)platinum(0)

The synthesis, characterization and X-ray crystal structure of 1,1-(rac-1,1′-bi-2-naphthoxy)-1-silacyclobutane (1) are reported and reveal an unusual planar conformation with a Si-βC distance of 2.302 (5) Å. Reaction of 1 with either stoichiometric or catalytic amounts of bis(1,5-cyclooctadiene)platinum(0) {Pt(cod)₂} gave 1,1′-bi-2-naphthol (BINOL), rather than the expected insertion products or polymer. A mechanism is proposed based on insertion of the Pt(cod) into 1 followed by hydride transfers via the Pt center to the 1,1′-bi-2-naphthoxy group. Anionic ring-opening polymerization of 1 is also reported and gave the poly(carbosilane) (4).     

Ultrasound assisted syntheses of a nano-structured two-dimensional mixed-ligand cadmium(II) coordination polymer and direct thermolyses for the preparation of cadmium(II) oxide nanoparticles

A nano-sized mixed-ligand Cd(II) coordination polymer, {[Cd(bpa)(4,4′-bipy)₂(H₂O)₂](ClO₄)₂}_n (1); bpa = trans-1,2-bis(4-pyridyl)ethane and 4,4′-bipy = 4,4′-bipyridine, has been synthesized by a sonochemical method and characterized by IR and ¹H NMR spectroscopy. Compound 1 grows in one dimension by two different bridging ligands, 4,4′-bipy and bpa. The thermal stability of compound 1 in the bulk form and nano-sized was studied by thermogravimetric (TG) and differential thermal analysis (DTA). The crystallinity of this compound was studied by X-ray powder diffraction and compared with an XRD simulation of the single crystal data. CdO nanoparticles were obtained by direct calcination at 500 °C and decomposition in oleic acid at 200 °C of the nano-sized compound 1. The obtained cadmium(II) oxide nano-particles were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM).     

Colorless poly(ether-imide)s deriving from 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride(BPADA) and aromatic bis(ether amine)s bearing pendent trifluoromethyl groups

A series of poly(ether-imide)s (III) characterized by colorless, highly solubility was synthesized from 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride(BPADA) and various fluorinated aromatic diamines (I_a-h) in DMAc via polycondensation to form poly(amic acid) (II), followed by chemical (C) and thermal (H) imidization. These polymers had inherent viscosities ranging from 0.60 to 1.3 dL/g. These polyimides were highly soluble in a variety of organic solvent such as amide-type, ether-type and chlorinated solvents. Moreover, these poly(ether-imide) films were almost colorless, with an ultraviolet-visible absorption cutoff wavelength below 390 nm and low b* value (a yellowness index) of 4.6-18.0. The III series showed strength tensile of 72-101 MPa, elongation at break of 11-25%, initial modulus of 1.5-2.0 GPa. The glass transition temperature (T_g) of III_a-h were in the range of 202-267 °C, and the decomposition temperature above 493 °C and left 40-65% char yield at 800 °C in nitrogen. They had the lower dielectric constants of 3.39-3.72 (1 MHz) and moisture absorptions in the range of 0.11-0.40%.