The main factors affecting the degradation of dyed polymeric matrices by the action of light (conversion of light energy into thermal energy, electron phototransfer, population of triplets, aggregation of dyes, oxidation-reduction processes, interaction with oxygen, including singlet) are analyzed and classified. Their dependence on the structure of the dyes, the nature of the polymer, and the method of dyeing of the latter is examined. Criteria for the creation of lightfast dyed matrices are formulated. Special attention is directed to contemporary light-sensitive materials in which the dye is covalently bonded to the polymer and to organic-inorganic compositions based on them.Dyed polymers are widely used in laser technology [1][2][3][4][5], media for writing and recording data [6-8], solar power [9][10][11][12], and optoelectronics [12][13][14][15]. Such polymeric materials have a series of operational advantages over dyed liquid materials on account of their more simple and more convenient construction, non-toxicity, and the possibility of working over a wide temperature range (from minus to plus temperatures) and under conditions of weightlessness. However, these advantages can only be realized to the full extent in the solution of various applied problems if dyed matrices with sufficient stability to the action of light are created. The aim of the present review was therefore to analyze, classify, and generalize methods of creating such matrices.
FACTORS GIVING RISE TO THE DEGRADATION OF DYED POLYMERS DURING THE ACTION OF LIGHTThe presence of absorbing microimpurities that are heated by radiation are responsible for the radiation damage of optically transparent polymers. Purification from such inclusions at the monomer stage leads to a substantial increase in the threshold of radiation damage in the obtained polymer. For instance, the purification of methylmethacrylate (MMA) by repeated slow distillation raises this threshold of polymethylmethacrylate (PMMA) from several times [16] to two orders of magnitude [17]. 0040-5760/09/4503-0143
An efficient chlorotrimethylsilane-promoted
synthetic protocol
for the preparation of functionalized fused β-trifluoromethyl
pyridines by cyclization of electron-rich aminoheterocycles or substituted
anilines with a trifluoromethyl vinamidinium salt was developed. The
efficient and scalable approach for producing represented trifluoromethyl
vinamidinium salt demonstrated huge prospects for further use. The
structure specificities of the trifluoromethyl vinamidinium salt and
their impact on the reaction progress were determined. The procedure’s
scope and alternative ways of the reaction were investigated. The
possibility of increasing the reaction scale up to 50 g and further
modification of obtained products was shown. A minilibrary of potential
fragments for 19F NMR-based fragment-based drug discovery
(FBDD) was synthesized.
The new efficient, convenient protocol for the synthesis of heteroannelated 3-cyanopyridines and pyrimidines starting from diverse aminoheterocycles and 3,3-dimethoxy-2-formylpropionitrile sodium salt was elaborated. The advantages and improvements of the procedure compared to previously known methods were shown. The scope and limitations of the method were determined. The impact of the structural features on regioselectivity was discussed. The preparativity, scalability and application scope of the elaborated protocol was demonstrated by the synthesis of five heteroannelated 3-cyanopyridines in up to 100 g quantities.
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