Coordination polymers containing 1D channels as selective luminescent probes

Two 3d-4f heterometallic coordination polymers {[Ln(PDA)3Mn1.5(H2O)3].3.25H2O}infinity with 1D channels were synthesized under hydrothermal conditions (PDA = pyridine-2,6-dicarboxylic acid; Ln = Eu (1); Ln = Tb (2)). The emission intensities of 1 and 2 increased significantly upon addition of Zn2+, while the introduction of other metal ions caused the intensity to be either unchanged or weakened. The case implies that 1 and 2 may be used as luminescent probes of Zn2+.     

Thermoresponsive shuttling of rotaxane containing trichloroacetate ion

A thermoresponsive rotaxane shuttling system was developed with a trichloroacetate counteranion of an ammonium/crown ether-type rotaxane. Chemoselective thermal decomposition of the ammonium trichloroacetate moiety on the rotaxane yielded the corresponding nonionic rotaxane accompanied by a positional change of the crown ether on the axle. The rotaxane skeleton facilitated effective dissociation of the acid, markedly lowering the thermal decomposition temperature.     

Coordination polymers. IX

Poly-(butanediol-1,4-adipate) and poly-(diethyleneglycol-succinate) polyesters and their ionized derivatives, containing Mg²⁺ and Zn²⁺ ions with different stoichiometric ratios to the chain-end COOH groups of the polyesters have been investigated by derivatograph.The thermal decompositions of the metal-containing polyesters differ significantly from those of the unionized polyesters. These differences are connected with the chemical repeating unit of the polyesters and the chemical nature of the metal ions, and proportional to the amount of the latter.An explanation is given of the catalytic effect of metal ions on the process of decomposition of the polyesters.

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Zusammenfassung Poly-(butandiol-1,4-adipat) und Poly-(diethylenglycolsuccinat) polyester und ihre «ionisierten» Derivate — mit Mg²⁺ — und Zn²⁺-Ionengehalt in verschiedenen stöchiometrischen Verhältnissen zu den endständigen COOH-Gruppen der Polyester — wurden im Derivatographen untersucht.Die thermische Zersetzung der metallhaltigen Polyester unterscheidet sich wesentlich von nicht-ionisierten Polyestern. Diese Unterschiede sind mit den sich wiederholenden chemischen Einheiten der Polyester und der chemischen Beschaffenheit der Metallionen verbunden, und proportional dem Anteil derselben.Es wird eine Erklärung des katalytischen Effekts der Metallionen auf den Zersetzungsvorgang der Polyester gegeben.

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-1,4 «» , Mg²⁺ Zn²⁺ . , «» . . .

     

Ferrocene containing polymers

Polymers with pendent ferrocene units are synthesized by radical and anionic methods. It has been demonstrated that polymer-analogous reactions are an attractive alternative to prepare those polymers. Polymers with ferrocene units in the main chain are available from interfacial condensation reaction between ferrocene-1,1′-dicarbonic acid dichloride with α, ω-diamines. Addition of ferrocene-1,1′-dithiol onto norbornadiene yields a polymer with repeating units from ferrocene disulfide and norbornene and nortricyclane end-groups. End-capping reactions of α, ω-dimercapto-telechelics with vinylferrocene yield polymers with ferrocene end-groups.     

Novel sulfur containing polymers

Sulfur containing polymers were synthesized by the addition of thiols to alkenes and alkynes. Although the polymer formation is explained on the basis of a radical intermediate these processes show typical characteristics of step growth polymerizations. These reactions have been applied for the syntheses of telechelics.     

Fluorine containing phosphazene polymers

In this paper we highlighted the synthesis, characterization, and practical exploitation of different types of polyphosphazenes substituted with fluorinated groups. There are several ways in which fluorine atoms can be inserted into polyphosphazenes, all of which leading to different polymers showing a wide range of characteristics. In general it is true that the insertion of fluorine atoms into phosphazene macromolecules leads to an enhancement of the thermal stability, flame resistance, low-temperature elastomericity, and chemical inertness of the phosphazenes obtained. The contribution of Italian research groups to the preparation and exploitation of organic commercial macromolecules grafted onto fluorinated polyphosphazenes is also reviewed.     

Electrochemical oxidation of double-stranded polybisnorbornenes containing linearly aligned ferrocene linkers

Seventy percent of the ferrocene moieties in double-stranded polybisnorbornenes containing linearly aligned ferrocene linkers are oxidised and each of the neighbouring monomeric units in these polymers may strongly interact with each other; the oxidised form of has been shown to be antiferromagnetic.     

Organosilane polymers: Formable polymers containing methylsilylene units

Organosilane polymers containing methylsilylene units were prepared by sodium condensation of MeHSiCl₂ alone or with R¹R²SiCl₂ (R¹ and R² = alkyl, aryl, or aralkyl) in a blend of toluene and dioxane followed by fast filtration under N₂. These polymers are readily soluble in common solvents and can be drawn into fibers or formed into films by molding, casting, or potting. They can be crosslinked by oxidation, irradiation, or hydrosilylation of vinylsilane in the presence of platinum complexes. The effect of the quantity of MeHSiCl₂ on molecular weights of copolymers was also discussed.     

Synthesis, structures, and magnetic properties of metal-coordination polymers with benzenepentacarboxylate linkers

Three hybrid organic-inorganic coordination polymers with benzenepentacarboxylate (BPCA) linkers, [Co3(C6H(COO)5)(OH)(H2O)3] (1-Co), [Zn3(C6H(COO)5)(OH)(H2O)3] (2-Zn), and [Co5(C6H(COO)5)2(H2O)12].(H2O)12 (3-Co), were synthesized hydrothermally and were characterized structurally and magnetically. 1-Co and 2-Zn are isostructural [C2/c; Z=8; 1-Co, a=19.5350(6) A, b=10.4494(4) A, and c=13.2353(5) A, beta=97.2768(8) degrees; 2-Zn, a=19.5418(9) A, b=10.3220(10) A, and c=13.4660(10) A, beta=98.455(10) degrees] with three-dimensional structures that contain [M6] secondary building units bridged by BPCA ligands. A different cobalt-based compound, 3-Co, forms at lower pH and lower reaction temperature. Its structure [P21/c; Z=2; a=12.6162(2) A, b=11.3768(2) A, and c=15.3401(3) A, beta=91.539(1) degrees] is a more loosely packed framework with free (noncoordinated) carboxylic groups pointing at water-filled cavities in the framework. The magnetic phase diagram of 1-Co established through detailed magnetic measurements shows a metamagnetic transition below TN=3.8 K. The less-packed compound 3-Co, on the other hand, remains paramagnetic above 1.9 K. The three compounds are the first examples of coordination polymers with benzenepentacarboxylate linkers and fill the gap of coordination polymers involving benzenepolycarboxylate linkers of the general type C6H6-n(COOH)n, where n=2-6.     

Plasma polymers containing sulfonate groups

Modification of plasma-polymers prepared from phenylsilane with sulfur trioxide was investigated by FT/IR spectroscopy and ESCA. The sulfonation of phenyl groups in the plasma-polymers occurred rapidly within 1 min when exposed to SO₃ gas. The S/C and O/C atomic ratios determined by ESCA for the modified polymers were 0.13₈ and 0.41₈, respectively. The sulfonation made the plasma-polymers electrically conductive. The conductivity was sensitive to moist atmosphere. The logarithm of the impedance at 120 Hz decreased linearly with increasing the relative humidity. The plasma-films containing sulfonate groups may be a new material for moisture sensor devices.     

Organosilane polymers: Formable polymers containing reactive side groups

Formable organosilane polymers containing various reactive side groups were synthesized by hydrosilylation of unsaturated compounds containing reactive groups with poly(methylsilane) in the presence of platinum complexes. These polymers have appreciable solubility in common solvents, can be molded or cast into films or drawn into fibers, and are photoactive.     

Crosslinked polymers containing adamantane groups

Diglycidyl ethers of 1,3-bis-(p-hydroxyphenyl)adamantane (BHPA) and 3,3'-bis-(p-hydroxyphenyl)-1,1'-biadamantane (BHPBA) were prepared and condensed with m-phenylenediamine and methyl tetrahydrophthalic anhydride to give polymers with good high temperature mechanical properties and good oxidative stability. These bisphenols were also condensed with formaldehyde to give phenolic resins containing adamantane moieties.     

Organoiron polymers containing azo dyes

The synthesis of cationic organoiron polymers with azobenzene moieties in their side chains has been accomplished via nucleophilic aromatic substitution and ring-opening metathesis polymerization (ROMP) reactions. Polyaromatic ethers and thioethers with azobenzene moieties in their side chains were functionalized with different chromophores to yield yellow-, orange- and red-colored polymers. Polynorbornenes with azobenzene-containing side chains were isolated following ROMP of their monomeric analogs. All of the organoiron polymers were soluble in polar organic solvents and underwent reversible electrochemical reduction processes. Photobleaching of the azobenzene-containing polymers was achieved in the presence of hydrogen peroxide. The metallated polymers had glass transition temperatures approximately 50 to 80°C higher than their organic analogs.     

Anion-templated rotaxane formation

The development of an acyclic chloride anion template in which the chloride anion is coordinatively unsaturated and available for subsequent complexation to various hydrogen bond donating components is described. This template orients a neutral hydrogen bond donating ligand and a pyridinium cation orthogonally to one another. Incorporation of second-sphere interactions between the ligand and the pyridinium cation improved the efficacy of the chloride template. These results were exploited in the construction of a chloride anion-templated [2]rotaxane which, after anion template removal, was studied with regards to its anion recognition properties. Encirclement of the neutral macrocycle around the dumbbell-shaped pyridinium cation in the [2]rotaxane produced a dramatic increase in its selectivity for chloride anions as compared to the noninterlocked cation. This is interpreted as a function of the anion template used to create the [2]rotaxane superstructure.     

Investigations of blends containing coil polymers and thermotropic main-chain polymers

Blends containing main-chain thermotropic, semiflexible polyesters and flexible-chain polymers (PC and PET) are investigated by calorimetry and microscopy. First results of studies about the mechanical behaviour by torsional pendulum are presented.