ESR STUDY OF RADIATION-RESISTANCE OF SOME AZACROWN AND THIACROWN ETHERS AT 77 K

Gamma-induced intermediates stabilized in ''kriptofix-21'', ''kriptofi x-22'', ''Kriptand-222'' and 18-ane-S-6 have been studied by ESR spect roscopy at 77-300 K. Apparently, radicals with H-atom abstraction from methylene group are the main paramagnetic products in diazocrown ethe rs while formation of both cyclic and uncyclic species is observed in 18-ane-S-6 at 77 K. Heating gamma-radiated thiacrown ether up to room temperature mainly results in the cleavage of macrocyclic C-S followin g by stabilization of uncyclic radicals. 18-ane-S-6 has a higher radia tion resistance by comparison with oxygen- and aza-containing crown et hers at low temperature gamma-radiolysis.