Spectra of poly

Figure 7.11 Methylene proton portion of the 220-MHz NMR spectrum of poly(methyl methacrylate) (a) predominately syndiotactic and (b) predominately isotactic. [From F. A. Bovey, High Resolution NMR of Macro molecules, Academic, New York, 1972, used with permission.]...

The absorption spectrum of poly(2-methoxy-5-(2 -ethyI-hexyIoxy)-/mra-phenyIene vinylene) (MEH-PPV) is shown in Figure 7-8a. Phcnylene-based conducting polymers such as MEH-PPV exhibit multiple absorption features extending well into... 

The PL spectrum and onset of the absorption spectrum of poly(2,5-dioctyloxy-para-phenylene vinylene) (DOO-PPV) are shown in Figure 7-8b. The PL spectrum exhibits several phonon replica at 1.8, 1.98, and 2.15 eV. The PL spectrum is not corrected for the system spectral response or self-absorption. These corrections would affect the relative intensities of the peaks, but not their positions. The highest energy peak is taken as the zero-phonon (0-0) transition and the two lower peaks correspond to one- and two-phonon transitions (1-0 and 2-0, respectively). The 2-0 transition is significantly broader than the 0-0 transition. This could be explained by the existence of several unresolved phonon modes which couple to electronic transitions. In this section we concentrate on films and dilute solutions of DOO-PPV, though similar measurements have been carried out on MEH-PPV [23]. Fresh DOO-PPV thin films were cast from chloroform solutions of 5% molar concentration onto quartz substrates the films were kept under constant vacuum. 

Example 1, Poly(vinyl alcohol). The first example is given for the carbon-13 spectrum of Poly(vinyl alcohol). Figure 2 shows a plot of the carbon spectrum and a peak listing with assignments from the user s database. The assignments constitute a difficult part of the analysis... 

Fig. 12 Representative circular dichroic spectrum of poly(A) treated with various concentrations of berberine (a), palmatine (b) and coralyne (c). a Reprinted from [206], b reprinted from [208] and c reprinted from [187] with permission from Elsevier...

NMR Spectra - The proton NMR spectrum of poly(N-pheny1-3,4-dimethy-lenepyrroline) (VII) had three singlet absorptions at 6 2.56, 4.81 and 7.60 respectively (Figure 10). The integration of these peaks showed a ratio of 4 4 5. The presence of exocyclic olefinic protons was not observed, indicating that 1,4- addition was predominant in the polymerization with little or no 1,2 addition taking place. 

Figure 9. IR Spectrum of Poly(H-Phenyl-3,4-Dimethylene pyrrole).

Figure 2. FTIR spectrum of poly(t-butyl styrene)-b-poly(t-butyl methacrylate) (10% TBMA by weight).

Figure 8. REDOR 13C NMR spectrum of poly(acrylic acid) (PA) imbibed with [3-13C]Ala/[15N]Ala (10 1 1 by weight). The bottom curve represents the echo spectrum of full sample (Sq) the top curve is the REDOR difference. (AS). Spectra were collected using the pulse sequence of Figure 2 with VR = 3 kHz Nc = 30.

Further evidence for these a-helix ROA band assignments in the extended amide III region comes from the ROA spectrum of poly-L-alanine dissolved in a mixture of chloroform (70%) and dichloracetic acid (30%), known to promote a-helix formation (Fasman, 1987), which shows strong positive ROA bands at 1305 and 1341 cm-1 (unpublished results), and of the cv-helix forming alanine-rich peptide AK21 (sequence Ac-AAKAAAAKAAAAKAAAAKAGY-NHg) in aqueous solution which shows strong positive ROA bands at 1309 and 1344 cm-1 (Blanch et al., 2000). 

M 0004. (From Tiffany and Krimm, 1969, Biopolymers 8, 347-359, 1969. Reprinted by permission of John Wiley Sons, Inc.) (B) CD spectrum of poly-L-proline II (sigma, molecular weight 55,000) as a function of temperature. (C) CD spectrum of polyglutamic acid at pH 7 as a function of temperature. (D) CD spectrum of poly-L-lysine at pH 7 as a function of temperature. Parts (B-D) are from Tiffany and Krimm (1972). Biopolymers 11, 2309-2316, 1972. Reprinted by permission of John Wiley 8c Sons, Inc. 

A study of the valence band photoelectron spectrum and the X-ray emission spectrum of poly(ethylene oxide) was carried out by Brena and co-workers [102] in order to understand the effect of conformation on the observed spectra. Up to 12 monomers were used in the calculations for the valence band photoelectron... 

Figure 2. IR spectrum of poly(5-methyl-l,4-hexadiene) prepared with a EttAlCl/ h-TiCl3 catalyst at 0°C in pentane solvent. Reproduced, with permission from Ref. 13. Copyright 1979, American Institute of Physics.

Figure 1. NMR spectrum of poly-iAysine having pendant adenine moieties...

Figure 6. IR spectrum of poly(l,4-phenyleneoxide) obtained by the electrolysis of phenol.

The H- and C-NMR spectroscopic data support the proposed primary structure of poly(Lys-25). The amide carbonyl resonances are particularly informative as these signals are well resolved in the C-NMR spectrum of poly(Lys-25) (Figure 4). An amide carbonyl resonance is observed at 174.9 ppm for poly(Lys-25) that does not appear in the spectrum of poly(Val-Pro-Gly-Val-Gly) [13]. The position and relative intensity of this resonance are consistent with a lysine amide carbonyl group within a peptide bond [14]. Moreover, the resonances of the amide carbonyl groups for other residues in the pentapeptide repeat are split due to the substitution of a lysine residue at position 4 in every fifth pentapeptide in Lys-25. In addition, the absence of splitting in amide carbonyl group of valine in position 4 (174.5 ppm) supports this assignment, as this residue is replaced by lysine in the fifth pentapeptide of the Lys-25 repeat. The presence of other resonances attributable to the lysine residue can be detected in the H- and C-NMR spectra of the Lys-25 polymer at levels commensurate with its... 

Fig. 9.28 Analysis of the CH-stretching region (3000-2800 cm ) and the amide I band around 1650 cm V (a) ER-FTIR spectrum of poly(2-ethyl-2-oxazoline) (PEOx) as grown on the triflate functionalized HUT SAM. (b) ER-FTIR spectrum of HUT SAM. (c) Subtraction result of (a)-(b). (d) Bulk spectrum of PEOx. In the spectrum to the left, a significant shift...

To demonstrate the usefulness of a wide spectrum of poly(aryl ethers) as reverse osmosis membrane materials. 

Effects of temperature and paramagnetic additives on the spectrum of poly(dichlorophenyleneoxide). The spectra of the polymers referred to in Figure 1 were all measured up to 120° in tetrachloroethylene. In no case did any significant change occur in the spectrum on heating. 

The delocalization of the conduction electron onto the side chains would be expected if the pendant groups were replaced with more electrophilic substituents than the phenyl group. However, this is not the case. Figure 22 shows the absorption spectrum of poly-(methylnaphthylsilane) radical anion. The absorption spectrum is very similar to that of the naphthalene radical anion, which implies that the unpaired electron is localized on the pendant group. Increase of the electron affinity of pendant groups does not necessarily cause the delocalization. 

Fig. 14.5 Infrared spectrum of poly(vinyl chloride) (a) transmittance and (b) absorbance.

Figure 8. 60-MHz H-l NMR spectrum of poly-2,4-hexadienyllithium in debenzene (38) living (A) and pseudoterminated (B).

Figure 2. ESR spectrum of poly(a-methyl styrene) irradiated at 77° to 0.6 Mrad. (A) a single 200 s scan, (B) accumulation of 150 scans.

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