C-13 NMR determination of the rotational diffusion coefficients of monomeric polyaromatic molecules

A methodology based on the measurement of C-13 relaxation times previously developed to describe the anisotropic reorientation of a planar asymmetric rotor has been applied for benzanthracene and fluoroanthene. The calculation of the rotational diffusion coefficients for these molecules existing in a pure monomeric form requires prior determination of their self-association constants. The results obtained confirmed those already found for chrysene and the carbon relaxation times of their respective dimers can be calculated.