SIMULATION OF LIQUID-PHASE THERMAL-REACTIONS OF RADIATION-INDUCED VINYLCYCLOPROPANE RADICAL CATIONS USING THE TECHNIQUES OF FROZEN FREON MATRICES AND LIQUID-PHASE SPIN-TRAPPING

Thermal transformations of vinylcyclopropane (VCP) radical cations gen erated by X-irradiation in a CF2ClCFCl2 Freon matrix were studied by E SR technique. It was shown that the primary radical cations converted to the distonic form dist(90,0)-C5H+ . (VII) upon warming of the irrad iated samples up to 110 K. This distonic form undergoes transformation to the 2-vinylallyl radical (XI) at 120 K; the 1-vinylallyl radical ( X) is formed at 135 K. The conversion of (VII) to (XI) occurs due to h ydrogen transfer from VCP to the radical cation (XI) via formation of an intermediate vinylcyclopropyl radical (IX) followed by ring opening . X-ray irradiation of 2,4,6-tri-tert-butylnitrosobenzene (BNB) soluti ons in vinylcyclopropane at 293 K results in the formation of BNB addu cts with n-alkyl (I), allyl (II), 1-vinylcyclopropyl (V), and 2-vinylc yclopropyl (III) and (IV) radicals. The yield of BNB adducts (III) and (IV) was found to be 70% of the total yield of the adducts. A certain part of radicals (IX) results from ion-molecule reactions of the prim ary radical cations. Ring opening in two kinds of vinylcyclopropyl rad icals results in the formation of 1-vinylallyl and 2-vinylallyl radica ls.