Poly five-membered rings

Allyl polymers are made by free-radical polymerization of diaHyl compounds, most frequently diallyl dimethyl ammonium chloride (DADMAC) [7398-69-8] forming a chain containing a five-membered ring (28) poly(DADMAC) [26062-79-3]. 

We also studied the structure of poly(N.N-dimethyl-diallyl-ammonium bromide) using poly(N,N-dimethy1-3,4-dimethylenepyrroli-dinium bromide) as a model system (16). These studies unequivocally confirmed that polydiallyl quaternary ammonium system consisted predominantly, if not exclusively, of five-membered rings linked mainly in a 3,4-cis configuration. By investigating synthetic polymers with defined structures and composition, it is hoped that some relationship between the polymeric structure and properties could be clarified. We now wish to report the 1,4-polymerization of N-pheny1-3,4-dimethylene pyrrolidine and the effects of oxidation and reduction of this polymer. 

Five-membered ring imides in cyclopolymers of N-substituted dimethacrylamides such as PSPDM can be hydrolyzed to amic acids under moderately basic conditions. The resulting N-substituted amide is extremely resistant to basic hydrolysis. Consequently, this basic hydrolysis approach can still not be employed for the preparation of head-to-head poly(methacrylic acid). 

Shobha et al. employed a novel sulfonated diamine containing a phosphine oxide moiety in the synthesis of a five—membered ring sulfonated poly-imide. The synthesis is shown in Figure 24. 

Cyclopolymerization of dialdehydes was extensively studied by Aso and his coworkers (50). It was remarkable that o-phthalaldehyde could be polymerized readily (5Z-53), because aromatic aldehydes such as benzaldehyde, isophthalaldehyde and terephthalaldehyde did not polymerize with common ionic catalysts. In addition, the poly[o-phthal-aldehyde] obtained was composed of only cyclic structural units. These results suggested that the driving force for the polymerization of o-phthalaldehyde was apparently attributable to the formation of the five-membered ring in the course of cyclopolymerization. The ceiling temperature of the polymerization of o-phthalaldehyde was calculated to be — 43° C from the relationship between the equilibrium concentration of the monomer and the polymerization temperature (51,52). 

In order to understand the polymer structures that are obtained in the polymerization of 1,6-heptadiynes, one needs to consider all possible polymerization mechanisms. If 1,6-hep tadiynes are subject to cyclopolymerization using well-defined Schrock catalysts, polymerization can proceed via two mechanisms. One is based on monomer insertion, where the first alkyne group adds to the molybdenum alkylidene forming a disubstituted alkylidene, which then reacts with the second terminal alkyne group to form poly(ene)s consisting of five-membered rings. Analogous to 1-alkyne polymerization, one refers to this type of insertion as a-insertion (Scheme 4). 

Fig. 10 C-NMR spectrum of poly(4-(ethoxycarbonyl)-4-(15, 2R, 5S)-(+)-menthoxycar-bonyl-l,6-heptadiyne) based on >96% five-membered rings and containing an alternating cis-trans st structure. Signals indicated by an asterix ( ) denote excess of ferrocene aldehyde used for initiator capping...

The C-NMR spectrum of poly(4-(ethoxycarbonyl)-4-(lS,2R,5S)-(+)-men-thoxycarbonyl-1,6-heptadiyne) indicates a polymer containing almost solely five-membered rings (Fig. 10). In addition, only one single set for each type of carbon was observed, indicative of a highly tactic base. Keeping the symmetry restrictions described above in mind, either a cis or trans-st structure can be assigned. 

Precipitation studies at comparatively high concentrations have shown that proanthocyanidins form complexes with poly(L-proline) as well as with poly(vinylpyrrolidone) (9,W). Figure 2 depicts the repeat units of poly(vinylpyrrolidone y and poly(L-proline). The L-prolyl unit contains one fewer methylene and has the remaining atoms rearranged so that the amide and five-membered ring become parts of the backbone of the chain. The results reported in the proceeding section might lead to the expectation that addition of poly(L-proline) to an aqueous solution of one of the fluorophores would produce 1/1(0) > 1. This expectation is not realized. Poly(L-proline) with M = 60000 does not produce I/l(0) > 1. Instead it quenches the fluorescence. For example, the values of I/l(0) for 3.6 X 10 5 M (+)-catechin in water are 0.75 and 0.41, respectively. 

In the cyclopolymerization of methacrylic anhydride(MA) as a typical 1,6-diene, five- and six-membered ring anhydride structures can be formed, respectively corresponding to intramolecular hh and ht addition of uncyclized radical. The IR spectrum of poly-MA has been tentatively compared earlier with that of poly-MA prepared by dehydration of poly(methacrylic acid)(37) no five-membered cyclized anhydrides were detected, any absorption at higher frequency due to the strain of a five-membered ring being absent. 

In addition, it should be noted that even at a rather lower temperature of 80°C the five-membered ring formation was observed in a very dilute solution, although the poly-MA obtained at a rather higher monomer concentration contained exclusively six-membered ring anhydride structures as was the case in the previous article (22) where the monomer concentration was 0.265 mole/liter, being low enough to be sure to obtain the almost perfectly cyclized poly-MA. 

A new type of enantioselective diene polymerization is found with cyclopolymerization of 1,5-hexadiene which leads to polymers with a saturated chiral main chain28,58>109. As catalyst, (—)-(7 )-[l,T-ethylenebis(4,5,6,7-tetrahydro-l-indenyl)]zirconium (/ )-binaphtholate is used in the presence of methylalumoxane to give optically active poly(methylene-1,3-cyclopentane) (3) with 68% trans configuration in the five-membered ring (diisotacticity). If the (S)-enantiomer of the ansa-metallocene with (ft)-binaphthol is used as catalyst then the opposite rotation of the polymer is observed58. 

Kawaguchi and coworkers at Teijin have prepared a series of polymers based on poly(diallyl amine), its copolymer with sulfur dioxide, and various terpolymers.39 The chemistry of this polymer synthesis is shown below. The patent description shows the diallylamine polymers to be polypiperidine (six-membered ring) derivatives, but there are a number of publications that show this monomer to produce preferably polypyrrolidine (five-membered ring) structures ... 

Poly-2,5-dihydropyrroles (e.g. 8) represent another class of extended Ti-system with pronounced basicity [13]. The aromatization of their protonated bases amplifies the susceptibility toward the proton attack. Aromatization of the five-membered ring and... 

Several other synthetic methods are also in principle feasible. For example, for the preparation of H-H poly(methyl methacrylate) the cyclopolymerization of meth-acrylic acid derivatives if directed exclusively to the five-membered ring formation (42), and for the preparation of H-H polymers of olefins disubstituted on one carbon atom, the Wurtz synthesis has become feasible. (Eqn. 6,7.)... 

Attempts to prepare H-H poly(methyl methacrylate) by radical cyclopolymerization of methacrylic anhydride and methacrylimides have given promising results (42). The cyclopolymerization must be directed to the exclusive formation of the unfavorable five membered ring intermediate. Cyclopolymers which consist of mixtures of five and six membered rings were obtained with five membered ring intermediates predominating (23,42,59). 

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