Anthracene Group

In compound (4) (Figure 12.15) the fluorescence of the anthracene group is quenched by electron transfer from both the crown ether unit and the amino group. The electron transfer processes from the crown ether and the amino group can be prevented by adding Na+ and H+, respectively. 

It will be shown in later sections that side groups such as aromatic azo or biphenyl units generate liquid crystallinity metal phthalocyanines and tetracyanoquino-dimethane generate electroactive domains and polyaromatic units such as naphthyl or anthracene groups alter the physical properties markedly as they attempt to align then-molecular axes or form stacks of side groups. 

Polymers with anthracene groups such as poly(9-vinylanthracene)46 48), poly(l-vinylanthracene) and poly(2-vinylanthracene)49 so), poly[ l-(2 -anthryl)-ethylmethacrylate]51 poly(vinyl-p-phenyl-9-anthracene)S2 55 and poly(9-p-expoxy-... 

Photoconductivity has been observed on polymers to which the active polynuclear aromatic groups had been added by chemical attachment. For example, poly(L-lysine) with anthracene groups is claimed to be useful in electrophotography65. Similarly, poly(p-alkyl glutamates) with the attached 9-anthryl, 9-anthryl-methyl and other groups were claimed to be photoconductive66. ... 

First, the authors prepared PEG with an anthracene group at one end of the polymer chain. Then, the modified polymer was treated with a-CD to formp5eudo-polyrotaxane. Finally, the p5eudo-polyrotaxane was capped with 9-anthracene carboxylic acid to obtain polyrotaxane (Scheme 10). The ratio of CD and monomer units was found to be 4 1 (ethylene glycol unit CD) by NMR. When a DMSO solution of a-CD-polyrotaxane was irradiated with visible fight (A > 340 nm) (500 W Xe lamp with UV cut filter) under argon, poly(Q -CD-polyrotaxane) was precipitated out. The NMR spectrum of the product showed broad resonance bands due to a-CD and PEG and the absence of the absorption bands due to monomeric 9-anthracene. Characteristic absorption and emission bands due to monomeric 9-anthracene have completely disappeared. 

In the preparation of a system of labeled polymers, it is advisable to use luminescent groups exhibiting the same chemical structure as that of the main type of markers. If necessary, the study of polymers containing the main type of LM may be supplemented by an investigation of the same polymers with a LM of anotter chemical structure. The authors used an anthracene group as the main type of LM for the following reasons. 

Anthracene groups attached to polymer chains as LM exhibit a combination of optical properties required for the study of the relaxation properties of polymers by the PL method. They are characterized by relatively hi values of the limiting polarization and the quantum yield of luminescence. Absorption and luminescence bands of anthracene groups occur in the spectral range convenient for experiments. 

The anthracene group readily participates in various homo- and heterolytic substitution or addition reactions The meso-positions (i.e. positions 9 and 10) of the... 

Anthracene-containing monomers of the methacrylic series (e.g. anthrylmethyl methacrylates) can also be used to obtain polymers with LM by copolymerization. The monomers of this type are successfully used for the introduction of LM (Table 1 LMj and LMa) into side groups not only of various methacrylate polymers (e.g. from methyl to cetyl- and cholesteryl methacrylates) also of other polymer types. In the latter case, it is advisable to use monomers in which the position 10 is substituted (e.g. by a methyl group). In this case, the probability of side homolytical reactions with the participation of anthracen groups con-sinderably decreases ... 

Investigations have shown that 9-anthrylcarbene generated by thermal or photoiytic decomposition of 9-anthryldiazomethane in a polymer solution, can be inserted into the C—H bonds of the mactomolecules . As a result, anthracene groups are covalently bonded to the macromolecules (Table 1 LMn). 

Usually, the amount of anthracene groups bonded to the macromolecules during the carbene reaction is small. Under the conditions employed, it does not exceed 10—15% of the initial amount of ADM and greatly depends on the polymer structure, the nature of the solvent, and the polymer concentration ... 

The reaction of 9-anthrylcarbene with the polymers can affect the C-H bonds of various groupings of the macromolecules. Hence, if a predominantly identical structure of the bridge between the anthracene group and the poisoner chain is required, it is advisable to use the carbene method for bonding the LM to polymers with one type of C—H bonds (polyethylene, poly(ethylene oxide) etc.). 

This method can be successfully used for polymers of the methacrylic series (the macroradicals of which do not react Iwmolytically with the anthryl group). It can also be applied to introduce LM into the chains of such polymers as polystyrene. However, in this case the copolymerization can be complicated by homolytic reactions between the growing macroradicals and the anthracene groups (see Scheme 1). Presumably, it is possible to avoid side reactions by low-temperature cationic poly-merization ... 

Fig. 48. Plot of relaxation time 6 versus viscosity for polystyrene labeled with Anthracene groups. (After Valeur and Monnerie ...

PAHs1 NA 0.6 mg/kg/day (intermediate, acenaphthene) 0.4 mg/kg/day (intermediate, fluoranthene fluorene) 10 mg/kg/day (intermediate, anthracene) Group 2A benz(a)anthracene, benzo(a)pyrene Group 2B benzo(b)fluoranthen e benzo(j)fluoranthene, ideno(1,2,3-c,d) pyrene Group 3 anthracene, benzo(g,h,i)perylene, additional PAHs Group B2 benz(a)anthracene, benzo(b)fluoranthene, benzo(a)pyrene, chrysene, dibenz(a,h)- anthracene, indeno(1,2,3-c,d)- pyrene Group D acenaphthylene, anthracene, fluoranthene... 

Fluorescence spectroscopy was used also as a detection tool in case of a peptide based [2]rotaxane [72]. It was observed that in polar solvents like dimethyl sulfoxide (DMSO) fluorescence emission spectra were virtually same like those of the thread alone. Since fluorescence origins in this rotaxane from anthracene group, it was concluded that hydrogen bonds linking the macrocycle to the anthracene-based stopper were broken and the macrocycle resided on the alkyl side of the thread. When the solvent was hardly polar like 1,4-dioxane, the macrocycle rest bonded to the anthracene stopper and the spectrum broadened and red-shifted. By mean of time-resolved fluorescence spectroscopy, the authors demonstrated that it was... 

The local structure of the P(2VN-alt-MA) in water brings the naphthalene and covalently bound anthracene groups into closer proximity than for better polymer solvents. 

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