Polyaromatic ethers

Solvatochromic probes have been used for a variety of applications like the study polarity of pure and mixed solvents [99], and the retention behavior in reverse-phase liquid chromatography [100] among other applications. Frechet et al. used 4-(N-methylamino)-l-nitrobenzene (p-MANB), as the chromophore, to probe the microenvironment of polyaromatic ether based dendrimers [101]. 

Fe-arene complexes have been employed for the same purposes as their Ru counterparts, namely, in the preparation of monomeric aryl ethers,463,486-488 polyaromatic ethers,489,490 and macrocyclic aryl ethers.491... 

Research Focus Synthesis of polyaromatic ether polyimides as adhesives by plasma or thermal treatment of the film surface. 

Sulfonation is very useful chemical modification of polymer, as it induces high polarity in the polymer changing its chemical as well as physical properties. Sulfonated polymers are also important precursors for ionomer formation [75]. There are reports of sulfonation of ethylene-propylene diene terpolymer (EPDM) [76, 77], polyarylene-ether-sulfone [78], polyaromatic ether ketone [79], polyether ether ketone (PEEK) [80], styrene-ethylene-butylene-styrene block copolymer, (SEBS) [81]. Poly [bis(3-methyl phenoxy) phosphozene] [82], Sulfonated polymers show a distinct peak at 1176 cm"1 due to stretching vibration of 0=S=0 in the -S03H group. Another peak appears at 881 cm 1 due to stretching vibration of S-OH bond. However, the position of different vibrational bands due to sulfonation depends on the nature of the cations as well as types of solvents [75, 76]. 

Preparation of Polyaromatic Ether Containing a Conjugated Pyridine... 

Ohno [1] prepared a polyaromatic ether containing an imide termini, (1), that had a lower dielectric and moisture absorption properties and ease of processability than the imide-free precursor. The imide-functionalized product was used to prepare molding. 

The reaction of the cationic polyether, 196, with sodium cyanide led to the isolation of the neutral adduct, 197.254 Demetallation of these adducts via chemical oxidation with 2,3-dichloro-5,6-dicyano-l,4-benzoquinone (DDQ) gave the nitrile functionalized polyaromatic ethers 198 (Scheme 2.52). 

Abd-El-Aziz. A.S. Afifi. T.H. Budakow.ski, W.R. Friesen, K.J. Todd. E.K. The first example of cationic iron-coordinated polyaromatic ethers and thioethers with azo dye-functionalized side chains. Macromolecules 2002. 35. 8929-8932. 

J. Lee, C.S. Marvel, Polyaromatic ether-ketone sulfonamides prepared from polydiphenyl ether-ketones by chlorosulfonation and treatment with secondary amines, J. Polym. Sci. Part A Polym. Chem. 22 (2) (1984) 295-301. 

Polyaromatic ethers coordinated to CpFe+ moieties have also been prepared via sequential S Ar reactions of chloroarene complexes with hydroquinone (189). The electrochemical behavior of cationic aromatic ether, thioether, and sul-fone complexes of cyclopentadienyliron has been studied using cyclic voltammetry and coulometry (190). Reaction of the aromatic ether complexes with sodium cyanide resulted in the formation of neutral adducts which imder-went oxidative demetallation to give the corresponding organic aromatic nitriles (191). 

The synthesis of a water-soluhle metallodendrimer containing six cationic cyclopentadienyliron moieties was also reported (249). This dendrimer was examined as a redox catalyst for the cathodic reduction of nitrates and nitrites to ammonia. Star-shaped polyaromatic ether complexes of cyclopentadienyliron were recently reported hy Ahd-El-Aziz and co-workers (250). These complexes contained up to 15 cationic cyclopentadienyliron moieties pendent to aromatic rings in the star branches (111). Electrochemical analysis of these star polymers showed that the iron centers underwent reversible reduction processes. 

The synthesis of polyaromatic ethers (37) and thioethers containing azobenzene dyes in their sidechains has been achieved. These polymers were prepared by reaction of cyclopentadienyliron-complexed azobenzene monomers with various dinucleophiles. These organoiron polymers were bright orange or red, and could be bleached by irradiating the polymer in a solution containing hydrogen peroxide. 

Abd-El-Aziz and coworkers have reported the synthesis of star-shaped polyaromatic ethers containing up to 15 cyclopentadienyliron cations pendent to aromatic rings. Polymer 42 is an example of a water-soluble / exa-metallic star complex. Electrochemical studies showed that reduction processes for the inner and outer iron complexes could be distinguished for the hexa- and nonametallic stars. 

Polyaromatic Ethers and Thioethers Coordinated to Cyclopentadienyliron Cations... 

The past few decades have seen increasing interest in the design of thermally stable polymers as replacements for metals and ceramics in the aerospace and automotive industries.Polyaromatic ethers and thioethers are two classes of thermally stable polymers that have been examined for this purpose because of their ability to withstand temperatures in excess of 200°C and their stabihty toward acids, bases, and organic solvents. Rigid polymers such as polyaromatic ethers and thioethers often exhibit limited solubility in organic solvents at room temperature, and their high melting points can limit their processabUity. 

The synthesis of polyaromatic ethers coordinated to cyclopentadienyliron moieties was achieved via nucleophilic displacement of the chloro groups from... 

DSC of the organic polythioethers provided the glass transition temperatures of these polymers. The values of these polymers were approximately 100°C lower than those observed for the polyaromatic ethers and about 50°C lower than those of the polyaromatic thioethers. This is due to both the flexible aliphatic spacers in the polymer backbones and the presence of thioether rather than ether bridges. The Tg values of polymers 12b-d were 33, 34, and 37°C, respectively. It can be concluded that increasing the length of the aliphatic spacers decreased the glass transition temperatures of these materials slightly. 

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