Knowledge Bank

When F atoms produced in a microwave discharge are codeposited with $CH3X(X-Cl,Br,I)$ in an argon matrix at 14 K, the products of two primary reaction channels are isolated, yielding heretofore inaccessible information regarding the reaction mechanism. A prominent infrared absorption can be assigned to the X-F stretching fundamental of the $CH3XF$ free radical reaction intermediate in each of these three systems. F-atom attack of the methyl group leads to the formation of a very weakly bound $F\cdots HCH2X$ complex, for which spectroscopic evidence is presented. This complex decomposes either spontaneously or upon excitation with visible radiation, producing the $H2CX$ free radical hydrogen-bonded to HF.