Synthesis and Characterization of Carbohydrate-Copolyhydrazides Containing Ether Bonds in the Monomer Unit

Abstract

A series of carbohydrate-containing copolyhyrazides having ether bonds were prepared by low temperature solution polycondensation. 2,3,4,5-tetra-O-acetyl galactaroyl dichloride was polycondensed with hydroquinone-1,4-diacetic acid dihydrazide (1), 2-bromo-,2-chloro, 2-nirohydroquinone-1,4-diacetic acid dihydrazide (2, 3 and 4, respectively) and isophthaloyl dihydrazide (5) in dimethylformamide and produced copolyhydrazides (6-10), respectively. Copoly {1-[2-(2,3,4,5-tetra-O-acetyl-galacto-tetritoldi-1,4-yl)-5-(1,3,4-oxadiazol-di-2,5-yl]-3-[2-(1,3,4-oxadiazole-di-2,5-yl)-benzene]}(11)wassynthesizedbydehydrative cyclisation of the polymer(10) using thionyl chloride. Also, polymer (10), under de-O-acetylation in methanolic ammonia, gave the de-O-acetylated polymer (12). All the present new polymers were characterized by elemental analysis and i.r. and ¹H-NMR spectroscopy. Their solubility, viscosity and physical properties are studied.     

Supramolecular polymer networks based on calix[5]arene chained poly(p-phenyleneethynylene) and C60 fulleropyrrolidine

Abstract

A poly(p-phenyleneethynylene) polymer (PCF[5]), bearing two π-rich cone-like calix[5]arene cavities (assembling cores) attached to a rigid p-phenyleneethynylene spacer, was synthesised by a Pd-catalysed cross-coupling reaction. UV–vis absorption and fluorescence spectroscopies combined with dynamic light scattering measurements provide evidence for the self-assembly of PCF[5] (homopolytopic host molecule) with a complementary C₆₀ fulleropyrrolidine (C₆₀-Pyr) guest in solution, in the construction of a supramolecular polymer network. Atomic force microscopy analysis of PCF[5]/C₆₀-Pyr highlights the formation of a bicontinuous network consisting of a uniform distribution of prominent structures, within a polymeric background forming a biphasic structure.     

MOLECULAR TRANSPORT OF ORGANIC LIQUIDS THROUGH POLYMER FILMS

Abstract

The molecular transport of small molecules through polymer films has been the subject of active research over almost three decades [1–8]. The main thrust in this area is either to accumulate a large body of experimental data to assess the stability of polymer films for extreme serviceability or to develop new theories which describe the phenomenology of transport processes, the latter often being studied in terms of three important parameters: permeation, diffusion, and solubility, in adition to the swelling phenomenon.     

Number-Average Molecular Weights from Viscosity Measurements during Random Degradation of Polymers

Abstract

Using the theories of random degradation of Montroll and Simha, relationships are derived among limiting viscosity number, degree of degradation, and number-average molecular weight for a polymer undergoing random degradation in a closed system. Relationships among these parameters are derived for initial distributions of the “coupling” and the monodisperse types. Computer programs have been written which rapidly provide reliable values of number-average molecular weights and degrees of degradation from measured viscosity data on polymers with these initial distributions undergoing random degradation.     

Blue-luminescent poly(p-phenylenevinylene) derivatives: Synthesis and effect of side-group size on the optical properties

New conjugated polymers based on separated PPV-type chromophores and incorporating different types of solubilizing side-groups (ethoxy: P1, hexyloxy: P2, dodecyloxy: P3 and benzyloxy: P4) were synthesized via Wittig polycondensation, using a series of bisphenol A-derived di(triphenylphosphonium) salts as starting monomers. The polymers are soluble in common organic solvents and their structures were confirmed by ¹H NMR, ¹³C NMR and FTIR spectroscopies. The optical properties of these materials were investigated by UV–vis absorption and fluorescence spectroscopies. In dilute solution, quasi-identical fluorescence spectra were obtained and all the polymers showed a blue emission (420, 445 nm) and a narrow spectrum. In thin solid films, the polymers show side-group-dependent optical behavior and, whereas the emission remains blue in the case of P2, P3 and P4, a green fluorescence was observed for the ethoxylated polymer P1. From cyclic voltammetry analysis, the electrochemical band gaps were estimated to be 2.99, 3.07, 3.15 and 3.06 eV for P1, P2, P3 and P4, respectively. Single-layer diode devices of the [indium tin oxide/polymer/aluminum] configuration have been fabricated and show relatively low turn-on voltages between 2.6 and 4.9 V.     

HgII-containing MOFs constructed from bis-benzimidazole-based ligand with highly selective anion-exchange capacity

Two Hg(II)-containing metal–organic frameworks (MOFs) based on 1,1′-(1,5-pentanediyl)bis-1H-benzimidazole (pbbm), {[HgBr₂(pbbm)]?·?DMF} _n (1) and [HgI₂(pbbm)]₂ (2), have been constructed to explore new and potent ion-exchange materials. Single-crystal X-ray diffraction shows that 1 features a 1-D zigzag chain framework, while 2 presents a dimeric structure in which two Hg(II) cations are bridged by two pbbm ligands. The significant differences of these MOFs indicate that the counteranions have impact on assembling and structures of the resultant MOFs. Remarkably, coordinated Br^? in 1 can be replaced completely when the solid polymer is treated with an aqueous solution containing I^?. Confirmation of retention of structure is provided by FT-IR spectra and the XRPD pattern. The thermal stabilities of 1 and 2 have also been investigated.     

The synthesis and solution properties of some rigid-chain,water-soluble polymers: Poly[N,N′-(sulfo-phenylene)phthalamide]s and poly[N,N′-(sulfo-p-phenylene)pyromellitimide]

Poly[N,N′-(sulfo-phenylene)phthalamid]es and poly[N,N′-(sulfo-p-phenylene)pyromellitimide] were prepared in water-soluble form and were found to have unique solution properties, similar in some respects to xanthan. The polymer most investigated, poly[N,N′-(sulfo-p-phenylene)terephthalamide] (PPT-S), is produced as the dimethylacetamide (DMAC) salt by the solution polymerization of 2,5-diaminobenzenesulfonic acid with terephthaloyl chloride in DMAC containing LiCl. The isolated polymer requires heating in water to dissolve; the resulting cooled solutions are viscous or gels at concentrations as low as 0.4%. They are highly birefringent, exhibit circular dichroism properties, and are viscosity-sensitive to salt. Solutions of this polymer mixed with those of guar or hydroxyethyl cellulose give significantly enhanced viscosity. The polymer is relatively low molecular weight, ca. 5000 estimated from viscosity data. Some meta and para isomeric analogs of PPT-S were prepared; these polymers have similar properties except they are more soluble in water, and higher concentrations are required to obtain significant viscosity. Poly[N,N′-(sulfo-p-phenylene) pyromellitimide] (PIM-S) was prepared similarly from 2,5-diaminobenzenesulfonic acid and pyromellitic dianhydride. Its aqueous solution properties are similar to those of PPT-S. It appears that these relatively low-molecular-weight rigid-chain polymers associate in water to form a network that results in viscous solutions at low concentrations.     

A four-coordinate cadmium(II) polymer for efficient adsorption of Congo red,kinetic, isotherm,fluorescence and antibacterial activity

A 3-D cadmium-based coordination polymer, [CdCl₂L]_n (1) (where L = 1,1-(1,6-hexanediyl)bis(1,3-dihydro-3-methyl-1H-imidazole-2-thione), was synthesized and structurally characterized. The capability of the polymer as an efficient sorbent for Congo red (CR) removal from aqueous solution has been evaluated. Compound 1 has a tetrahedral arrangement with a CdS₂Cl₂ core. L in 1 is bidentate to two neighboring Cd^II centers via the methimidazole sulfurs to create 1D chains propagating along the c-axis. The remaining coordination sites are occupied by two terminal chlorides. The chains are further stabilized by intermolecular C–H?Cl hydrogen bonds between the chlorides and hydrogens of the imidazole rings. Parallel chains stack in the 3-D structure. The Cd^II polymer sorbent was characterized by infrared spectroscopy, elemental analysis, UV–vis, solid fluorescence and X-ray single-crystal diffraction. Sorption kinetics were studied by three kinetic models, second order, Elovich and intraparticle diffusion. The results indicate that the mechanism of the sorption process followed Elovich kinetic model. Sorption equilibrium was also studied with Langmuir, Temkin, and Freundlich isotherm models. The sorption process followed the Temkin isotherm. MIC, MBC, and DNA cleavage activities of 1 were also studied. Furthermore, the UV–vis and solid state fluorescence spectra of 1 were measured.     

Template construction of a series of supramolecular coordination polymers via 6,7-dihydro-5H-[1,4]diazepino[1,2,3,4-lmn][1,10]phenanthroline-4,8-diium cation

Five cation-induced complexes, (phen-dzp) [ZnBr₃N₃] (1), (phen-dzp) [ZnCl₂Br₂] (2), (phen-dzp) (H₃O)₂ [Fe(CN)₆] (3), (phen-dzp)₂ [Cu₂I₆] (4), and [(phen-dzp)(Ag₂Br₄)] _n (5) [phen-dzp?=?(C₁₅H₁₄N₂)²⁺, 6,7-dihydro-5H-[1,4]diazepino[1,2,3,4-lmn][1,10]phenanthroline-4,8-diium], have been synthesized via self-assembly in solution. The crystal structures of 1–3 show that they all crystallize in monoclinic systems with mononuclear structures. Compound 4 is a binuclear coordination polymer. Complex 5 possesses a 2-D supramolecular layer with the organic cation phen-dzp trapped in it; interestingly, each inorganic polymeric planar layer is composed of large, decagon rings formed by sharing four Br^? and four [Ag₂Br₄] quadrilateral units with six adjacent decagon rings. The results provide insights into template effects of synthetic approaches on the construction of supramolecular compounds. The structures of 1–5 have been characterized by elemental analysis, infrared spectra, and single-crystal X-ray crystallography. Solid-state photoluminescence properties of 1–5 have been determined.     

Synthesis and structures of two cobalt(II) coordination networks formed from aromatic polycarboxylates and 1,4-bis(imidazole-1-ylmethyl)benzene

Two Co(II) coordination polymers, [Co(Hbtc)(bix)] _n , (1) and [Co(1,4-bdc)(bix)H₂O] _n (2) (bix = 1,4-bis(imidazole-1-ylmethyl)benzene; H₃btc = benzene-1,3,5-tricarboxylic acid; 1,4-H₂bdc = benzene-1,4-dicarboxylic acid) have been synthesized under hydrothermal conditions and structurally characterized. X-ray structure analysis reveals that in polymer 1, 2D infinite grid-like frameworks are interconnected by hydrogen-bond interactions to result in a 3D supramolecular architecture, in which the three carboxylate groups of the H₃btc molecule adopt three different coordination modes. In polymer 2, 1,4-bdc ligands with cobalt atoms construct 1D zigzag chains which are bridged by bix ligands to form a 3D framework.     

Dependence of Polymer Chain Entanglements on the Solution Concentration

For the viscometric determination of molecular weights of polymers, sufficiently dilute solutions have to be used so that entanglements of the polymer chain are absent. The concentration of the polymer should be such that the relative viscosity (η_r) lies in the range 1.1–1.5 [1]. Similarly, for molecular weight determination by light scattering, the suggested concentration for polymer with weight-average molecular weight ( M _w ) > 10⁵ is 0.5 wt%; for those with M _w < 10⁵, up to 1% may be used [2].

The limits of polymer concentration for such measurements are not clearly known. On dissolution, the polymer molecules adopt a more or less extended configuration whose shape depends on the structure and molecular weight of the polymer, the properties of the solvent, and the temperature

[3]. The molecules of flexible linear polymers acquire a coiled configuration due to free rotation about the C-C bonds. When a dilute solution satisfies theta conditions, the polymer molecules are free from all kinds of interaction and move freely. Then their solution properties could possibly be related to their end-to-end distance. Based on this concept, our attempt to establish the permissible limits of polymer concentration for dilute solutions of several polymers of different molecular weights is reported here.     

A Pb2+-based coordination polymer with 5-(1H-tetrazol-5-yl)isophthalic acid ligand: structure and photoluminescence

A coordination polymer, [Pb₂(OH)(tzia)]·2H₂O (1), has been prepared by solvothermal reaction of 5-(1H-tetrazol-5-yl)isophthalic acid (H₃tzia) and Pb(NO₃)₂. The polymer 1 is based on an unprecedented centrosymmetric tetranuclear [Pb₄(OH)₂(COO)₄(ttaz)₂] cluster linked by a multidentate tzia ligand, affording a 2-D 3,6-connected kgd layer. The adjacent layers are further jointed by Pb?O interactions to form a 3-D supramolecular framework with a rare (3,8)-connected tfz-d; UO₃ topology. Photoluminescent properties of H₃tzia, 1, and 1-desolvated have been further investigated, and it was interesting to find that 1-desolvated due to the removal of lattice water molecules reveals stronger photoluminescence than 1.     

Advances in the Production of Poly(Lactic Acid) Fibers. A Review

Abstract

Poly(lactic acid) has recently seen its development as a textile fiber. With the resin prepared from agricultural feedstock, the fiber has properties typical of a synthetic fiber, while still being fully biodegradable. This article is an attempt to review recent research developments which have taken this polymer from a specialty suture material to a commodity fiber. Various approaches for the preparation of fiber grade polymer from monomers and its conversion into textile grade filament are discussed. Both solution spinning and melt spinning technology along with physical properties of the fibers are discussed in detail.     

Syntheses and structures of [Ag(etu)3]2SO4 and [{Cu(etu)I}3] n (etu = ethylenethiourea): a new μ 3–S coordination mode for etu

[Ag(etu)₃]₂SO₄ (1) and [{Cu(etu)I}₃] _n (2) (etu?=?ethylenethiourea) have been synthesized by reaction of etu with Ag₂SO₄ or CuI and their crystal structures determined. In 1 both crystallographically independent Ag⁺ ions are trigonally coordinated by three monodenate etu ligands. Complex 2 is composed of a one-dimensional polymer assembled by cyclic [Cu(etu)I]₃ trimers. In the [{Cu(etu)I}₃] _n polymer, the chair-type Cu₄S₂I₂ core is formed by μ₃–S bridging etu ligands and this represents a new coordination mode for etu. The Cu⁺ ions have a distorted tetrahedral coordination geometry.     

Solution versus solid-state electropolymerization of regioregular conjugated fluorenone–thienylene vinylene macromonomers—voltammetric and spectroelectrochemical investigations

We present detailed voltammetric and spectroelectrochemical studies of poly(2,7-bis(5-[(E)-1,2-bis(3-octylthien-2-yl)ethylene])-fluoren-9-one) (PTVF)—a conjugated polymer consisting of thienylene, vinylene, and fluorenone subunits. PTVF can be easily obtained either by electropolymerization of its monomer ((2,7-bis(5-[(E)-1,2-bis(3-octylthien-2-yl)ethylene])-fluoren-9-one) [TVF]) dissolved in the electrolytic solution or via solid-state electropolymerization of a thin film of the monomer deposited on the electrode. UV-vis-NIR spectroscopic data indicate that the latter method leads to a polymer of a smaller degree of polymerization (DP). The possibility of the formation of a polymeric conductor on a transparent conductive substrate such as indium tin oxide, in situ, via solid-state electropolymerization, combined with its postpolymerization transformation into an organic semiconductor by electrochemical dedoping, is technologically very attractive and makes TVF and its polymer very promising materials for applications in organic electronics. Contribution to the International Workshop on Electrochemistry of Electroactive Materials (WEEM-2006), Repino, Russia, 24–29 June 2006.     

Copper(II) complexes with singly condensed tridentate Schiff-base ligands incorporating 1-benzoylacetone

Two copper(II) complexes [CuL¹Cl]_n (1) and [CuL²Cl] (2) with singly condensed tridentate Schiff-base ligands [HL¹ = 6-amino-3-methyl-1-phenyl-4-azahex-3-en-1-one and HL² = 6-diethylamino-3-methyl-1-phenyl-4-azahex-3-en-1-one] have been synthesized and structurally characterized by X-ray crystallography. Complex 1 is a single-chloro-bridged one-dimensional polymer, whereas 2 is a monomeric square-planar complex. The H-bonding interactions of the amine hydrogen and the non-bonding interactions of phenyl groups in the Schiff base play important roles for the structural variations.     

Syntheses and crystal structures of two Zn(II) complexes, [Zn(Fura)2(2,2′-bipy)(H2O)] and [Zn(μ-dnbc)2] (Fura=Furoic acid, 2,2′-bpy=2,2′-bipyridine,dnba=3,5-dinitrobenzoic acid)

Two Zn(II) complexes, [Zn(Fura)₂(2,2′-bpy)(H₂O)] (1) and [Zn(µ-dnbc)₂] (2), have been synthesized and characterized by X-ray diffraction and IR spectra. 1 is a quaternary Zn(II) complex with ZnN₂O₃ configuration distorted square pyramid geometry; 2 is a Zn(II) coordination polymer with 1D double-helical chains bridged by 3,5-dinitrobenzoic acid.     

THE FORMATION AND STABILITY OF MICROSCOPIC EMULSION FILMS OF AQUEOUS SOLUTIONS OF POLY (ACRYLIC ACID) AND ACRYLIC ACTD-VINYLACETATE COPOLYMERS

ABSTRACT

The effect of polymer volume concentration C, pH and ionic strength (NaCl concentration, CNal) of solution, polymer molecular mass, acetate groups' content in a polymer chain, and ethanol concentration on the stability of microscopic emulsion films (MEF) stabilized with the adsorption layers of poly(acrylic acid) (PAA) and acrylic acid-vinylacetate copolymers (PAA-VA) has been studied.

The kinetics of MEF thinning under the conditions when two heptane drops in a polymer solution are brought into contact and pressed with a permanent force has been studied.

The free energy ? F of interaction in the film has been evaluated on the basis of measuring the film thickness Hf by photometry and determining the film profile in the Plateau region.     

Synthesis of Oligomer and Styrene Polymer-supported Calix[4]arene Derivatives and Selective Extraction of Fe3+

Five new polymeric compounds containing more than one calix[4]arene have been synthesized by reacting an oligomer with 5,11,17,23-tetrakis[(diethylamino)methyl]-25,26,27,28-tetrahydroxycalix[4]arene (L1), 25,27-dimethyl-26,28-dihydroxy-p-tert-butylcalix[4]arene diketone (L2), and p-nitrocalix[4]arene (L3), and chloromethylated polystyrene with 25,27-dimethyl-26,28-dihydroxy-p-tert-butylcalix[4]arene diketone (L4) and p-nitrocalix[4]arene (L5). These compounds were studied by the selective extraction of Fe³⁺ cation from the aqueous phase into the organic phase and was carried out by using compounds L1–L5. It was observed that the polymer support attached to the lower rim of p-nitrocalix[4]arene was the most efficient carrier of Fe³⁺ in the extraction process.     

Pivalate Bridged High Spin Manganese(II) and Iron(II) Polymers

Antiferromagnetic Mn(II) polymers of general formula {[L₂Mn(μ-OOCCMe₃)₂][Mn₂(μ-OOCCMe₃)₄]}_n (L = 1,2-phenylenediamine (3) and 4,5-dimethyl-1,2-phenylenediamine (4)) were synthesized from [Mn(μ-OOCCMe₃)₂(HOEt)] _n (1) polymer and arenediamines in MeCN solution. The tetranuclear cluster Fe₄(μ₃-OH)₂(μ-OOCCMe₃)₄(η²-OOCCMe₃)₂(EtOH)₆ (5) was prepared by reacting FeSO₄·7H₂O with KOOCCMe₃ in EtOH and was used as starting pivalate iron(II) agent in further reactions. The thermolysis of 5 in MeCN was shown to result in a ferromagnetic polymer [Fe(μ-OOCCMe₃)₂] _n (6) containing tetrahedral iron(II) atoms. Cluster 5 was found to react with o-phenylenediamine giving rise to ferrimagnetic polymer [Fe(μ-OOCCMe₃)₂(HOEt)]_n (7). The reaction 7 with 2,6-diaminopyridine in MeCN results in binuclear antiferromagnetic complex (2,6-(NH₂)₂C₅H₃N)₂Fe₂(μ-OOCCMe₃)₄· 4MeCN (8). However the reaction of 4,5-dimethyl-1,2-phenylenediamine with polymer 7 yields a polymer {[L₂Fe(μ-OOCCMe₃)₂][Fe₂ (μ-OOCCMe₃)₄]} _n (9), which is an analogue of the manganese polymer 4. All newly synthesized compounds were characterized by the by X-ray diffraction studies and magnetic measurement. Dedicated to Professor Ilya I. Moiseev in recognition of his outstanding contribution to cluster chemistry