Polyazines

The interaction of PCSs with nucleophilic reagents was studied by us we took the reactions of hydrazine and phenylhydrazine with polyazines, poly(schiff base)s, and other polymers containing conjupted C=N bonds as an example40,41, U7,258. ... 

C. Thermal degradation of polyazines of this type occurs with marked exothermal effects, accompanied by a practically complete evolution of nitrogen as N2 from the polymer. 

Thermal stability of polyazines of the third group, i.e., polymers with conjugated sections separated by aliphatic blocks, is determined by the thermal stability of the latter. The degradation process takes place gradually, and it is not accompanied by any considerable heat effects41,117-. ... 

Interaction of PCSs with electron acceptors and donors results in molecular complexes with partial or complete charge transfer. In particular, detailed investigations involved charge transfer complexes (CTC) of poly (schiff base), polyazines, products of thermal transformations of PAN and a number of other PCSs129, 238, 241 243, 267. ... 

We have already pointed out that the reduction in conjugation efficiency in PCSs is followed by a short-wave shift of the CTC transfer band. This accounts for the fact that poly(schiff base)s and polyazines having conjugated sections separated by oxygen and sulfur atoms are characterized by a short-wave shift of the transfer band of CTC with all acceptors compared to the respective polymers having no interruption of the conjugated chain. This shift may reach 20-50 nm. 

It seems possible, however, that in the polyazines the order could be reversed, with n-electrons higher than w-electrons, since the effect of heteroatoms in increasing the n orbital ionization is likely to be cumulative. 

The spectroscopy and emission properties of many azines (mono-and polyazines) have been extensively studied and reviewed.11,70,71 The following facts are pertinent ... 

In the application of oxidation dyes, aromatic amines form insoluble polyazine derivatives in the fiber (azine dyes [81]). Synthesis proceeds in several steps in a hydrochloric acid medium by oxidation (e.g., with dichromate). For the chief representative of this group, aniline black, the chromophore consists of dibenzo-pyran rings. Oxidation dyes are rapidly decreasing in importance because aniline and other aromatic amines as well as the bichromate used for oxidation are toxic. The colors produced by aniline black are characterized by a full bluish black shade and excellent fastness. Since they are easily reserved, they are still used occasionally for printing grounds. For individual processes, see [82],... 

Substituent Rate Factors (Logarithmic Values) from /V-Methylation of Pyridine Derivatives by Methyl Iodide in DMSO to be Used for Predicting the Regioselectivity in Polyazines Quaternization... 

Diazines, polyazines, and azapyrylium salts participate in inverse electron demand DielsAlder/retro-DielsAlder-type reactions with electron-rich dienophiles leading to pyridines . 1,2,4-Triazines react with enamines and enol ethers to give pyridines as illustrated in Scheme 162 <2004T6021, 2004CC508>. 

The calculation of polyazine radical parameters continues to attract the theoreticians.168-173... 

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