SN-119 CIDNP - CALCULATIONS AND EXPERIMENT

Sn-119 CIDNP effects observed in the photolysis of 2-methylpropanoyltr ipropylstannane, Pr3SnC(O)CHMe(2), are in good agreement with those ca lculated in the frames of the diffusion model of radical pair (RP) the ory. Simulations performed for arbitrary magnetic field strengths have shown that mainly S-T-0 transitions in RPs where the Zeeman term is c omparable with the hyperfine interaction are responsible for CIDNP for mation in the fields of modem NMR spectrometers (several tesla). CIDNP in lower magnetic fields result from S-T-+,T-- transitions in all RPs involving tin-centered radicals. In high fields these transitions lea d to the appearance of net polarization in the RPs where the Zeeman te rm is well below the hyperfine interaction.