Reversible conformation change of free radicals in X-irradiated glutarimide single crystals studied by ENDOR

Allyl type radical formation in X-irradiated glutarimide crystals studied by ENDOR and ENDOR-induced EPR

“…The basis for this was the observation 9 that the ENDOR spectra obtained at 150 K exhibited new resonance lines in addition to those already assigned for radicals I and II. An additional issue addressed in our previous study 5 was to clarify the internal dynamics observed to occur in radical I. Similar dynamics, probably involving libration motions of C b -H bonds, was observed for radical II during the present work but requires further studies.…”

“…Single crystals of glutarimide were grown from aqueous solutions, the details of the crystal growing were as described previously. 5 The crystal structure of glutarimide was determined by X-diffraction. 10 The crystals are monoclinic with space group P2 l /c.…”

“…4 The radicals previously observed in X-irradiated glutarimide single crystals at room temperature were typical of C-centered p-electron radicals, formally formed by scission of C-H bonds. 5 Ring opening of glutarimidyl radicals does not take place in liquid solution, contrary to the succinimidyl case. [6][7][8] The main aim for the research reported in this work was to investigate if, and eventually to what extent, ring opening and/or other fragmentation processes occur upon X-irradiation in the solid glutarimide matrix by studying the types of radicals that are stabilized using high-resolution variants of EPR spectroscopy, i.e.…”

EPR and ENDOR studies of single crystals of 2-oxazolidinone X-irradiated at 295 K

“…3,4 In single crystals of glutarimide, the imidyl-type primary radical was not observed at any temperature, and the two dominant radical species are formed by net H-abstraction of one of the methylene protons of the system. 7 Ring-opened structures were not formed among the main radiation-induced species. A recent re-analysis of this system, however, has revealed evidence for a ring-opened species to about 15% of the total radical concentration.…”

Gama Işınları ile Işınlanmış Amino Asit Türevlerinin EPR ve Simulasyon Metodu ile İncelenmesi

“…Electron Paramagnetic Resonance (EPR) has generally used for the investigation of free radicals formed in the ɣ-irradiated biological systems and identification [1][2][3][4][5]. EPR spectroscopy has been identificated the radicals and electronic structures in irradiated amino acids and derivatives.…”