Poly proposed structures

All of the soluble polymers (1 and 3-6) give high resolution NMR spectra (1H, 13C, and 31P) that are completely consistent with their proposed structures. As observed for other types of poly(phosphazenes), the 31P chemical shifts of these alkyl/aryl substituted polymers are consistently ca. 15-30 ppm upfield from those of the analogous cyclic trimers and tetramers. Some important structural information is provided by 13C NMR spectroscopy, particularly for the phenyl/alkyl derivatives 3 and 4. These polymers are rare examples of phos-phazenes that contain two different substituents at each phosphorus atom in the chain. Thus, they have the possibility of being stereoregular. The fact that the structures are completely atactic, however, is confirmed by the observation of three doublets in the P-Me region of the 13C NMR spectrum (ca. 22 ppm) in a 1 2 1 intensity ratio. 

Figure 11 Proposed poly(imine) structure observed on platinum anodes during polymerisation...

Spontaneous polymerization of 4-vinyl pyridine in the presence of polyacids was one of the earliest cases of template polymerization studied. Vinyl pyridine polymerizes without an additional initiator in the presence of both low molecular weight acids and polyacids such as poly(acrylic acid), poly(methacrylic acid), polyCvinyl phosphonic acid), or poly(styrene sulfonic acid). The polyacids, in comparison with low molecular weight acids, support much higher initial rates of polymerization and lead to different kinetic equations. The authors suggested that the reaction was initiated by zwitterions. The chain reaction mechanism includes anion addition to activated double bonds of quaternary salt molecules of 4-vinylpyridine, then propagation in the activated center, and termination of the growing center by protonization. The proposed structure of the product, obtained in the case of poly(acrylic acid), used as a template is ... 

Figure 3. Comparison of the proposed structures for poly (<-caprolactone) (left) from Ref. 17 (right) from Ref. 18...

Figure 3 Proposed structure of the active center of poly(l-vinylimidazole)-Cu complex.

Different mechanistic interpretations of the formation of an alternating propylene/carbon monoxide copolymer of poly(spiroketal) structure were considered [107, 478, 480, 481, 489]. Any reasonable proposal, however, needs to take into account the nature of the end groups in the copolymer chains. To date this has not been possible owing to the low solubility of the copolymer in solvents other than hexafluoroisopropanol however, this solvent, probably because of its acidic nature, causes transformation of the poly(spiroketal) structure into an isomeric poly(ketone) structure [489]. The formation of a cyclic polymeric structure could be favoured by minor entropy loss due to the intramolecularity of the process [480,481] and by the peculiar conformational situation of the poly(ketone) structure [491]. 

Poly-VAd can form polymer complexes with poly-VUr8 or with poly(uridylic acid)-(poly U)8 16. The formation of triple-stranded (2 poly U poly-VAd) and double-stranded (poly U poly-VAd) structures containing poly-VAd loops were proposed for the poly U poly-VAd system16. The formation of these complexes seems to depend on the reaction condition. 

Scheme 11. Proposed Mechanism to Explain Poly(acrylamide) Structure...

The structure of the naphthalenophane-containing cyclopolymer was also clarified in the same manner as for poly(St-C3 St) (22). All spectroscopic results shown in Table IV are consistent with the proposed structure for the polymer. Again the recent cyclocodimerization finally concluded the presence of naphthalenophane units in the polymer clearly (21). 

Fig. 7 Proposed structure of poly ethyl a-[(allyloxy)methyl]acrylate [80a].

When supramolecular polymers are treated with bulky stopper groups, they may form poly[2]rotaxane daisy chains [45-53]. Harada et al. [31] treated 6-p-aminoCiO-a-CD (40 mM) with 2M excess 2,4,6-trinitrobenzenesulfonic acid sodium salt (TNBS) as bulky stoppers in aqueous solutions. The resulting precipitate was found to be mainly a cyclic trimer by H NMR and TOF mass spectra. After purification of the crude product, the 2D ROESY spectrum of the cyclic trimer shows cross-peaks between phenyl protons close to an amino group and secondary hydroxyl groups (0(2)H). A trinitrophenyl group is found at the secondary hydroxyl group side. A proposed structure of a cyclic trimer (cyclic daisy chain) is shown in Fig. 3.12. Kaneda et al. [38] reported the preparation of cyclic di[2]rota-xane fashion constructed tail-to-tail by azobenzene derivatives of permethylated a-CDs and showed its computer-generated supramolecular structures (Fig. 3.13). Easton et al. [39] also reported the preparation of cyclic di[2]rotaxane constructed by stilbene-appended a-CDs in tail-to-tail fashion (Fig. 3.14). Kaneda et al. [40]... 

STRUCTURES The Structure of poly(phenylsilsesquioxane) probably depends upon the method of preparation. There is much debate still in the literature about its structure. All of the structural types or combinations of the types shown may exist. The first table below summarizes the proposed structures and the evidence for such structures. 

FIGURE 9.12. Proposed structure for poly(5-carboxyindole). (From Ref. 35.) Note added in proof Subsequent work by Mackintosh and Mount [J.G. Mackintosh and A.R. Mount, J. Chem. Soc., Faraday Trans. 90, 1121 (1994)] has shown that the polymerization of 5-carboxyindole leads to the formation of a polymer of asynunetric trimers of 5-carboxyindole rather than the linear polymer postulated by Bartlett et al in their original work. 

Figure 5.8 Proposed structure of poly[l]. (Reproduced from Advanced Materials, 2002, 14, 826, C. Masalles, J. Llop, C. Vinas, F. Teixidor, with permission from Wiley-VCH.)...

Figure 9.16. (a) the chemical structure of the triblock copolymer poly(ethylene oxide)-poiy(propylene oxide)—poly(ethylene oxide) (PB076-PP029-PE07 ) and (b) the proposed structure of the emulsion droplets. TMB = 1,3,5-trimethylbenzene. 

Figure 4 Proposed structure formation of poly(NIPAM-Z>Zock-VBZ) diblock copolymer in normal and inverse micelles in aqueous media.

Figure 44 Proposed formation mechanism of polythiophene/protein wire bundles (a) structural image of polythiophene with an all trans backbone configuration (left). Structure of BI monomer (PDB file lAPH) with a tyrosine side chain shown for comparison (right), (b) Proposed interaction between a partially unfolded BI monomer (gray) and two polythiophenes (green), (c) Transmission electron microscopy of the wires after incubation for 6h at 65 °C and proposed structure, (d) Left Two fiuorescence micrographs of the corresponding poly thiophenes shown on the right (scale bar 20 pm). (Reproduced with permission from Ref. 78. Wiley-VCH, 2005.)...

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