Polyrotaxanes: Past,present and future

The threading process in polysebacate-crown ether rotaxanes prepared by the acid chloride method was examined by systematic study of the effects of 1) the size of the macrocycle, 2) the equilibration time between the diol and the macrocycle before addition of sebacoyl chloride, 3) the molar ratio of crown ether to diol, 4) the length of the α,ω-diol and 5) the temperature of equilibration and reaction. It was concluded that the threading process is based on hydrogen bonding interactions of the diol with the crown ether, predisposing the latter to threading as the ester bond is formed. The lack of “stoppers” or “knots” at the chain ends is believed to allow loss of macrocycles in the initial precipitation, after which loss of macrocycles is very slow due to chain folding. All of these polyester rotaxanes, except the 30-crown-10 case, display crystalline phases for both the backbone and the cyclic components. All of the polyrotaxanes complex alkali metal ions.     

聚十二烷二元酸酯及其共聚酯的合成

通过直接熔融缩聚法合成了一系列聚十二烷二元酸酯，用GPC、^1H—NMR、FTIR对产物进行了表征，并讨论了预聚酯合成时催化剂浓度和种类、预聚反应温度、预聚初始醇酸摩尔比对聚合反应的影响。结果表明，在所选的三个催化剂体系中，氮化亚锡二水合物与对甲苯磺酸复合催化剂的催化效果最好；最佳反应条件：n对甲苯横酯／n二元酸=0．0021～0．0032，反应温度为160～180℃，醇酸摩尔比范围为1．05—1.10。     

Influence of a hydrophobic diol on the micellar transitions of Pluronic P85 in aqueous solution

Micellization behavior of an amphiphilic ethylene oxide-propylene oxide-ethylene oxide tri-block copolymer Pluronic P85 [(EO)(26)(PO)(39)-(EO)(26)] in aqueous solution and in the presence of a hydrophobic C(14)diol (also known as Surfynol104) was examined by physico-chemical methods such as viscometry, cloud point (CP) and scattering techniques viz. dynamic light scattering (DLS) and small angle neutron scattering (SANS). The addition of diol decreases the cloud point and gelation temperature of aqueous Pluronic P85 copolymer solution. DLS and SANS measurements of the polymer in aqueous solution indicated micellar growth and sphere to rod transition in the presence of diol. Surfynol 104 is a sparingly water soluble diol surfactant with a solubility of approximately 0.1 wt%. However, up on addition to Pluronic solution, diol gets incorporated in the block copolymer micelles and leads to structural transition of the micelles. An increase in the temperature and the presence of added sodium chloride in the solution further enhances this effect. The addition of hydrophobic C(14)diol increases the hydrodynamic size and aggregation numbers of the micellar system. The micellar parameters for the copolymer in the presence of C(14)diol are reported at different temperatures and added sodium chloride concentrations.     

Synthese funktioneller Carbonsäure-Silylester

Synthesis of Functional Carboxylic Acid Silylester Di-tert-butylsilandiol reacts with organic acid chlorides to chlorosilanoles R₂Si(OH)Cl 1 (R = t-Bu). The phosphoric acid silylester 2 is obtained from 1 and POCl₃. Lithiated halogenosilanoles react with carboxylic acid chlorides to give silylesters ( 3 – 7 ). Lithium (trimethyl-acetoxy)silanolate 8 is obtained in the reaction of the lithiated diol with the chloride of trimethylacetic acid. The analogous reaction with benzoyl chloride lead to the formation of the bis(benzoic acid) silylester 9 . The condensation product 10 is obtained in the reaktion of the lithiated aminosilanol (t-Bu)₂Si(NH₂)OLi with trimethylacetic acid chlorid and condensation of the formed ester with aminosilanol.     

Synthesis of novel perfluoroalkyl ether derivatives

A series of novel fluoroether-containing monomers has been designed and prepared based on the commercially available perfluoroalkyl ether acid fluoride. Treating acid fluoride with allyl alcohol, 2-hydroxyethyl methacrylate or N-allylmethylamine allowed for the direct formation of corresponding vinyl-containing fluorinated monomers. High yields of the fluorinated epoxy monomers could be obtained from acid chloride with glycidol; meanwhile, fluorinated diol was prepared from diethanolamine or 3-amino-1,2-propanediol. Moreover, fluorinated monoamine, fluorinated monoalcohol and fluorinated dichloride were also obtained. Most of these fluorinated monomers were liquid at room temperature and exhibited good solubility in common organic solvents.     

Aromatic-aliphatic copolyesters—I. Synthesis and characterization

Copolyesters have been synthesized by interfacial polycondensation of 2,2-bis(4-hydroxyphenyl)-propane or phenolphthalein as aromatic diol and ethylene glycol or polyethylene glycol as aliphatic diol in various mole ratios with terephthaloyl or isophthaloyl chloride. Chemical compositions, dilute solution viscosities and solubility behaviours of these polymers have been investigated. The introduction of aliphatic diol in aromatic polyesters influences T_g, softening point, chemical resistance and thermal stability.     

Ring-expansion polycondensation of 2-stanna-1,3-dioxepane (or 1,3-dioxepene) with dicarboxylic acid chlorides

2,2-Dibutyl-2-stanna-1,3-dioxepane 1 (or 1,3-dioxepene 2) were prepared from 1,4-butane (or 1,4-butene) diol and dibutyltin dimethoxide. They were polycondensed at 80°C in n-heptane with adipoyl-, suberoyl, sabacoyl chloride and with decane-1,10-dicarbonyl chloride. In the case of suberoyl chloride and 2,2-dibutyl-2-stanna-1,3-dioxepane reaction time, temperature and stoichiometry were varied to optimize both the molecular weight and the fraction of cyclic polyesters. With a slight excess of the dicarboxylic acid chlorides, only macrocyclic polyesters were obtained in all cases. The resulting cyclic polyesters were characterized by viscosity measurements, by ¹H and ¹³C NMR and by MALDI-TOF mass spectrometry.     

Photoswitchable architectural polymer: Toward azo‐based polyamidoamine side‐chain dendritic polyester

A versatile approach to the synthesis of novel polyamidoamine (PAMAM) side‐chain dendritic polyester (SCDPE) possessing azobenzene motifs in the polymeric core is described and displayed reversible cis–trans (E/Z) isomerization upon exposure to UV light. A polymerization reaction was conducted in solution using ester‐terminated PAMAM dendritic diol ( 1a , G 3.5) and azobenzene dicarboxylic acid chloride in the presence of triethylamine. PAMAM dendritic diol 1a as well as SCDPE ( 1 ) were thoroughly characterized by means of IR and NMR (¹H and ¹³C) spectroscopies. The intrinsic viscosity of 1 at 36 °C in CHCl₃ was found to be 0.38 dl/g. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 4182–4188, 2001     

Isomeric 2,6-pyridino-cryptands based on dibenzo-24-crown-8

Cryptands 4 and 5 were synthesized from cis- and trans-bis(hydroxymethylbenzo)-24-crown-8 by reaction with pyridine-2,6-dicarboxylic acid chloride in 42 and 48% yields, respectively. The new cryptands form pseudorotaxanes with the paraquat derivative N,N'-bis(beta-hydroxyethyl)-4,4'-bipyridinium bis(hexafluorophosphate) ("paraquat diol", 6): Ka=1.0x10(4) and 1.4x10(4) M-1, respectively. The cryptands also form complexes with ammonium hexafluorophosphate. Formation of the paraquat/cryptand-based pseudorotaxanes can be switched off and on in a controllable manner on the basis of the cryptands' abilities to complex KPF6 strongly, providing a new mechanism for control of molecular shuttles. K+ displaces paraquat diol from the cryptands, converting yellow-orange solutions to colorless; however, addition of 18-crown-6 binds the KPF6 and allows the colored cryptand-paraquat complex to reform. Crystal structures are reported for both cryptands, both paraquat diol-based pseudorotaxanes, both NH4PF6 complexes, and both KPF6 complexes.     

A Concise Synthesis of 2‐Amino‐1,2,3,4‐tetrahydronaphthalene‐6,7‐diol (‘6,7‐ADTN’) from Naphthalene‐2,3‐diol

2‐Amino‐1,2,3,4‐tetrahydronaphthalene‐6,7‐diol ( 2 ; 6,7‐ADTN) was synthesized starting from naphthalene‐2,3‐diol in seven steps and with an overall yield of 44%. Methylation of naphthalene‐2,3‐diol with dimethyl sulfate, followed by Friedel? Crafts acylation with AcCl, gave 2‐acetyl‐6,7‐dimethoxynaphthalene. 2‐Acetyl‐6,7‐dimethoxynaphthalene was converted to 6,7‐dimethoxynaphthalene‐2‐carboxylic acid by a haloform reaction. Birch reduction of the carboxylic acid with 4 mol‐equiv. of Na in liquid ammonia afforded 1,2,3,4‐tetrahydro‐6,7‐dimethoxynaphthalene‐2‐carboxylic acid, from which 2 was obtained by a Curtius reaction, followed by hydrogenolysis and demethylation.     

Hydrophobically modified poly (acrylic acid) using calix[4]arene derivative. Ionophoric properties and extraction abilities toward alkali metal cations

p‐t‐Butyl calix[4]arene diol (distal cone) (1) was grafted with poly (acrylic acid) (PAA) to obtain hydrophobically modified PAA (PAA‐C) bearing calixarene moieties. The grafting method includes the direct esterification reaction of PAA with calixarene diol 1 which was carried out in a system of tosyl chloride (TsCl), pyridine (Py), and N,N‐dimethylformamide (DMF). The grafting yield was studied using different molar ratios of PAA to calix[4]arene diol 1, temperature, and reaction time. The chemical composition of the PAA‐C was studied by IR and ¹H NMR spectroscopy. Also, the morphology of PAA‐C was evaluated by scanning electron microscopy. The PAA‐C had different solubility and thermal properties. The extraction ability measurements of modified PAA toward alkali metal cations (Na⁺, K⁺, Cs⁺) and Ag⁺ showed a remarkable efficiency and selectivity of PAA‐C toward Na⁺. The main goal of this work was to design hydrophobically modified PAA with binding ability that is suitable for ion selective membranes and chemical sensor devices such as ion‐specific electrodes, semipermeable membranes, and quartz microbalances. Copyright © 2009 John Wiley & Sons, Ltd.     

Synthesis of cyclic oligo(ethylene adipate)s and their melt polymerization to poly(ethylene adipate)

We present here the first synthesis of cyclic oligo(ethylene adipate)s(COEAs) via pseudo-high dilution condensation reaction of adipoyl chloride with ethylene glycol, and the synthesis of corresponding poly(ethylene adipate)(PEA) via the melt polymerization of COEAs. The structure of COEAs was characterized and proved by 1H-NMR and MALDI-TOF mass measurements. The effects of organic base, reaction temperature and the ratio of adipoyl chloride to ethylene glycol on the yield of COEAs were studied, and the optimum reaction condition was revealed. PEA, a diacid and diol based semi-crystalline green aliphatic polyester, was synthesized by the melt polymerization of COEAs using Ti(n-C4H9O)4 as catalyst and 1,10-decanediol as initiator at 200 °C, which follows the polycondensation-coupling ringopening polymerization method. Our strategy should be applicable to the synthesis of versatile aliphatic polyesters based on diacid and diol monomers, which have potential applications as biocompatible and biodegradable materials.     

Synthesis and characterization of coronanes: multicyclopropane-fused macrocyclic arrays

Stepwise macrocyclization of the all syn-trans-1,15-quinquecyclopropanedimethanol (4) with iso- and terephthaloyl chlorides and 4,4'-methanediyl-dibenzoic acid (28) gave the corresponding coronanes 22, 23, and 32. The same protocol was used with all syn-trans-1,21-septecyclopropanedimethanol (5) and 2,3-naphthalenedicarboxylic acid to obtain the macrolide 27. Direct macrocyclization of diol 4 and 1,10-phenanthroline-2,9-dicarbonyl chloride (33) and 2,2'-bipyridine-4,4'-dicarbonyl chloride (35) gave the coronanes 34 and 36, respectively. Ring closing metathesis (RCM) of the diene 42 using Cl2(Cy3P)2Ru=CHPh (48) (Grubbs's catalyst) gave the macrocyclic lactone 45. The structures of coronanes 22, 23, 32, 34, 36, and 45 were confirmed by X-ray crystallographic studies which showed the cyclopropyl chain to adopt very differing conformations throughout the series. Several of the macrocycles have significant free pathways through their ring centers, and in the case of compound 34 there is a water molecule hydrogen bonded within the ring. This latter compound has the potential to act as a chiral ligand to metal centers.     

Polymers from a levopimaric acid–acrylonitrile Diels–Alder adduct: Synthesis and characterization

The Diels–Alder adduct of levopimaric acid with acrylonitrile was efficiently prepared from resin acids. Excellent addition reaction yields (ca. 95%) were obtained. The adduct was converted into polyamides by polycondensation with diamines. When the same adduct was subjected to a dehydrodecarboxylation reaction, a novel ketone dinitrile derivative was obtained. This trifunctional product was also converted into polyamides by polycondensation with diamines. When the ketone dinitrile was hydrolyzed in the presence of alkalies and the reaction product was chlorinated, a ketone diacid chloride was obtained. A polyester was synthesized by the polycondensation of the diacid chloride with a diol. The structures of the Diels–Alder adduct, ketone dinitrile derivative, ketone diacid chloride, and polymers were established by means of elemental analysis, IR and NMR spectroscopy, and molecular weight determinations. Both the polyamides and the polyester were low‐molecular‐weight polymers soluble in polar solvents. The thermal behavior of the monomers and polymers was evaluated by thermogravimetric analysis. The thermal studies showed that the polymers were fairly thermostable substances, except the polyester, which appeared to be a substance with good thermal stability. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 6308–6322, 2005     

Thermotropic copolyesters prepared by solution polycondensation with TsCl/DMF/pyridine condensing agent

When mixtures of terephthalic acid (TPA) and 1,6-naphthalenedicarboxylic acid (NDC) or 4,4′-dicarboxydiphenylether (DCDPE), TPA, and isophthalic acid (IPA) were reacted in pyridine (Py) with Tosyl chloride (TsCl)/DMF/Py to activate the diacids, the reaction mixture was soluble in Py, despite each of the separately activated diacids being insoluble. The solubility of the activated diacids was examined at a variety of acid compositions and temperatures. It was expected that a competitive reaction among the diacids with an aromatic diol in solution might be different from those in the melt, resulting in a different distribution of the acids in the copolymers. The TPA/NDC-phenylhydroquinone and DCDPE/TPA/IPA-chlorohydroquinone copolymers were prepared in solution using TsCl/DMF/Py as the condensing agent and the transition temperatures of these liquid crystalline copolyesters were compared to those obtained by melt copolycondensation. A practical depression of the transition temperature by the solution polycondensation was observed. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 3710–3714, 1999     

Preparation of anhydrochymotrypsin diol silica as selective adsorbent for affinity chromatography of peptides with aromatic amino acids at C-termini

Summary Anhydrochymotrypsin (AHC), a catalytically inert derivative of chymotrypsin in which the serine-residue active site has been converted chemically to a dehydroalanine residue, was immobilized on diol silica by activation with trifluoroethanesulfonyl chloride. A AHC-diol-silica column was used for high-performance affinity chromatographic separation of peptides with aromatic amino acids at their C-termini from other peptides. Faster separations were achieved.     

[60]Fullerene diol issued from pentaerythritol derivatives

A new [60]fullerene diol is synthesized in good yield, in two steps starting from reaction of C₆₀²⁻ anion with the benzylideneacetal derived from 2,2-bis(iodomethyl)-1,3-propanediol. The corresponding [60]fullerene bis-mesylate is also formed in a similar way starting from bis-iodo bis-mesylate compound in the same series. The scope of this fullerene diol in synthesis is exemplified by its easy esterification with 4-formyl benzoyl chloride.     

Solution polycondensation of isophthalic acid/terephthalic acid and tetrachlorobisphenol A of low polymerizability with tosyl chloride/dimethylformamide/pyridine improved by the introduction of comonomers of smaller sizes

The copolycondensations of a mixture of equal parts of isophthalic acid and terephthalic acid with tetrachlorobisphenol A (TC‐BPA) and various aromatic diol comonomers were performed with a tosyl chloride/dimethylformamide/pyridine condensing agent. The reaction with bisphenols containing nonpolar substituents yielded better results than the reaction with polar groups did. Dihydroxybenzenes smaller in size than bisphenols of two benzene rings, especially chlorohydroquinone and chlororesorcinol, were satisfactorily incorporated and yielded copolymers of high inherent viscosities and weight‐average molecular weights (by gel permeation chromatography). The results of the copolycondensations were examined with sequence distributions in the resultant copolymers by NMR and were well evaluated by the ratio of the length of comonomer unit segments to TC‐BPA unit segments. Homopolycondensation with TC‐BPA in the presence of dichlorobenzenes as additives was also promoted to some extent. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 821–830, 2003     

Preparation of semi-interpenetrating polymer networks containing polystyrene/polyvinyl chloride blends. Some mechanical properties

Blends of polystryene, polyvinyl chloride and cross-linkable monomers were studied. The networks were based either on styrene with divinylbenzene or on ethyl acrylate with hexane diol diacrylate. Parameters governing the obtaining of macroscopically homogeneous plates were optimized. The tensile and impact resistance of such materials were tested. A preliminary approach to their structure was also carried out.     

Interference of ascorbic acid in the sensitive detection of dopamine by a nonoxidative sensing approach

The electrochemistry of a poly(anilineboronic acid)/carbon nanotube composite was studied in the presence of dopamine and ascorbic acid. To understand the binding affinity of dopamine and ascorbic acid to the boronic acid functional groups in the composite, the association constants between the diol groups in dopamine and ascorbic acid and the boronic acid were experimentally determined using a fluorescence-based binding assay. The results demonstrate that ascorbic acid could severely interfere with the detection of dopamine in nonoxidative boronic acid-binding approaches: Ascorbic acid was able to electrocatalytically reduce the fully oxidized polyaniline backbone during the electrochemical oxidation process; similarly to dopamine, ascorbic acid was also able to bind to the boronic acid groups through its planar diol group even though the binding affinity is much lower. The examination of the dopamine transduction mechanism and ascorbic acid interference mechanism in this nonoxidative approach will benefit the design of future boronic acid-based sensors.