Muonium addition to cyanides

Muonium, the light radioactive isotope of hydrogen, was found to add to the CN triple bond of acetonitrile, cyanoacetate, cyanide and tetracyanocadmate(II) with room temperature rate constants, K sub(M), of 5.1 x 107, 7.7 x l07, 3.0 x 109, and 1.7 x 1010 (all M-1s-1), respectively. While Cd(CN)4-2 is diffusion controlled with an activation energy of approximately 15 kJ/mole the others appear to be activation controlled as with cyanoacetate's activation barrier of approximately 35 kJ/mole. Kinetic isotope effects range from 0.7 to 24