Poly spectral properties

Table 3 Spectral Properties of -Poly(malic Acid) and Its Salts...

Reversible oxygen binding has also been examined using poly(ethyleneimine)-cobalt complexes in aqueous solution. Cobalt(II) complexes of linear and branched poly(ethyleneimine) in aqueous solution are able to form with oxygen a p-peroxo adduct as is evidenced from stoichiometry and spectral properties 107). 

Polymerization of I. I was polymerized in flame-dried equipment under N 2 at -40 °C as follows. A 25-mL round-bottom flask equipped with a poly(tetra-fluoroethylene) (Teflon)-covered magnetic stirring bar and rubber septum was charged with I (1.2 g, 10.9 mmol) (5, 6), THF (10 mL), and either HMPA (5 drops) or TMEDA (5 drops). n-Butyllithium (0.8 mL, 1.2 M, 0.96 mmol) was added slowly to this mixture. The mixture quickly became thick. The mixture was stirred for 1 h at -40 °C and then warmed to -20 °C, and saturated aqueous ammonium chloride was added. The organic layer was separated, washed with brine and water, and dried over molecular sieves (4 A). After filtration, the solvent was removed by evaporation under vacuum 1.10 g (92% yield) of polymer was isolated. The yields of polymer ( 2%) and their spectral properties were identical regardless of whether HMPA or TMEDA was used as cocatalyst. With n-butyllithium-TMEDA, a polymer with Mw and Mn of 158,000 and 69,000, respectively, was obtained, whereas with n-butyl-lithium-HMPA, a polymer with My, and M of 120,000 and 30,400, respectively, was isolated. 

The first example of an azobenzene amphiphile polyelectrolyte complex was reported by Shimomura and Kunitake. They used poly(vinylsulfate) 23 to stabilize an ammonium amphiphile (21, n = 5). Because the tertiary ammonium head group is rather large and the distance of the ionic sites in poly(vinylsulfate) is rather small, the packing of the amphiphiles is not sipti-ficantly loosened by the complexation. In this case, the influence of the poylelectrolyte on the spectral properties and the photoisomerization is small. 

Our interest in this approach towards catalyst synthesis originated from previous studies by Ghosh and co-workers on the spectral properties of intercalated poly(pyridyl) Ru(II) chelates adsorbed on smectite clays [3-6]. Previous work by the authors on clay-catalysed organic reactions is noted [7-9]. 

The excitation spectra of -RB in a frozen non-polar solvent (MTHF) do characterize the absorption spectra. These spectra can be compared with those of monomeric models for -RB under identical conditions and with the spectral properties observed for soluble Poly-RB. 

Fig. 6. Correlation between the chain length and spectral properties of poly(ADP-ribose) as determined at 5°C in 4 Af NaCl. Molecular filtration of polydis-perse poly(ADP-ribose) on Sepha-dex G-50 was carried out as described [10]. 0.75 ml aliquots of each of the tube s contents were added to 2.25 ml of 5 M NaCl solution (final concentration of NaCl was 4 M). The average chain length of poly(ADP-ribose) was determined in several fractions and is shown as...

Minaga T, Kun E (1983) Probable helical conformation of poly(ADP-ribose) - the effect of cations on spectral properties. J Biol Chem 258 5726-5730... 

Shinkai and coworkers reported cationic polythiophene 11 obtained by the direct oxidative polymerization of the tetraalkylammonium salt of a thiophene monomer (Scheme 16.3). The molecular weight of the polymer was not determined however, its absorption and fluorescence spectral properties were consistent with the polythiophene backbone structure. Schanze and coworkers reported the use of a direct polymerization method to prepare the cationic poly(arylene ethy-nylene) 8 that features a backbone that alternates thienylene-ethynylene and phenylene-ethynylene repeat units (Scheme 16.4). Thus, polymerization of the cationic tetraalkylammonium substituted 1,4-diiodobenzene with 2,5-diethynyl-thiophene via a Sonogashira coupling protocol catalyzed by Pd(0)/Cu(I) catalyst in aqueous/DMF afforded 8. The resulting polymer was purified by aqueous dialysis using an 8 kD molecular weight cutoff membrane. As with the previous examples, the molecular weight of the cationic CPE was not determined. 

Figures 3 a, b, c summarize the typical spectral IR and Visible region spectral properties of devices. The large light/dark variation ( dynamic range ) is clearly seen therein as well. An interesting property, discussed at length in conjunction with electrochemical data in one of our earlier communications (4), is that the Visible- and IR-region reflectances vary in tandem between applied potentials of -1.1 V and 0.0 V, but behave in an opposite fashion between 0.0 and +0.8 V. As we discussed earlier (5a), this is due to transitions between die various poly(aniline) states reduced non-conductive leuco-emeraldine, partially oxidized conductive doped-emeraldine, and highly oxidized and again non-conductive pemigraniline.

The chromicity of poly(aryleneediynylene)s (PAE) is discussed and described in diis contribution. Four different types of PAEs will be scrutinized a) dialkyl-poly(para-phenylene-ethynylene)s (dialkyl-PPEs), b) dialkoxy-PPEs, c) acceptor substituted PPEs, and d) heteroaryleneethynylenes that contain benzothiadiazole units in their main chain. We will shortly describe their syntheses and then discuss their spectral properties in absorption and emission in solution and in thin films. 

Aspects relevant to color tuning of the spectral properties of thiophene-based polymers have been discussed [87]. With this aim, poly(silanylene-block-thiophene) in which oligothiophene blocks alternate with oligosilanylene blocks were synthesized (Scheme 14.24). 

Duchoslavova Z, Sivkova R, Hankova V, Sedlacek J, Svoboda J, Vohlidal J, Zednik J (2011) Synthesis and spectral properties of novel poly(disubstituled acetylene)s. Macromol Chem Phys 212(16) 1802-1814. doi 10.1002/macp.201100160... 

Stanimirov S, Vasilev A, Haupt E, Petkov I, Deligeorgiev T (2009) Synthesis and spectral properties of novel fluorescent poly(oxyethylene phosphate) tris(P-diketonate) europium (III) complexes. J Fluoresc 19 85-95... 

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