Reactions of recoil 11C atoms with c-C 6H 12, C 6H 6 and C 6(CH 3) 6

Abstract

A comparative study has been made of the reactions of recoil 11C atoms with c-C 6H 12, C 6H 6 and C 6(CH 3) 6. Use was made of group separations of labelled recoil products by HPLC techniques. Reaction mechanisms are discussed on the basis of primary reactions of 11C atoms: 1, H-abstraction leading to 11CH; 2, insertion into a CH bond, leading to an excited carbene that can decompose or isomerize to a stable monomeric compound. Thermal singlet carbenes can also insert into the CH bond of another molecule (yielding dimeric compounds) whereas in the case of C 6H 6, a triplet carbene can add to the aromatic ring (leading to the formation of higher polymers); and 3, addition to the aromatic ring of C 6H 6 can also lead to an excited carbene, but such a process is thought to be sterically hindered in the case of C 6(CH 3) 6.