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High and low molar mass 3‐alkyl‐1,4‐pentazadienes. Synthesis and photolysis
Author(s) -
Baindl Andreas,
Lang Armin,
Nuyken Oskar
Publication year - 1996
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.1996.021971214
Subject(s) - chemistry , thermostability , alkyl , substituent , photochemistry , gel permeation chromatography , molar mass , thermal stability , photodissociation , polymer chemistry , differential scanning calorimetry , chromophore , photosensitivity , polymer , organic chemistry , materials science , physics , optoelectronics , thermodynamics , enzyme
High and low molar mass compounds containing the 3‐alkyl‐1,4‐diarylpentazadiene group were synthesized in the reaction of aromatic diazonium salts with primary amines. These high nitrogen compounds are characterised by high photosensitivity and thermostability. The photolytic decomposition was studied in detail with respect to the substitution at the aromatic moieties and at N 3 of the pentazadiene chromophore. Electron donating aromatic substituents were found to increase photosensitivity and decrease thermostability whereas electron withdrawing aromatic substituents cause higher photolytic and thermolytic stability. A little influence of the alkyl group at N 3 on the photosensitivity of the pentazadiene group was observed. Photolysis was investigated by means of UV/Vis spectroscopy and obeys first order kinetics for some compounds under investigation. Gel permeation chromatography (GPC) measurements during photolysis of pentazadiene polymers prove that irradiation with UV light causes irreversible chain degradation. Thermolysis in bulk was studied for all compounds by differential scanning calorimetry (DSC). In contrast to the results of the photolysis the alkyl substituent at N 3 has an effect on the thermostability of the pentazadiene chromophore.