From these studies it has generally been understood that solvent effects on hydrogen abstraction reactions are significant when looking at O-H bond abstraction, primarily because of the O-H bond's ability to participate in hydrogen bonding networks, but that the effect on C-H bond abstraction is negligible. Despite this assumption, Koner and co-workers generalized these effects to C-H and Sn-H bonds . They explain the results as a stabilization of the abstracting species in polar solvents, rather than the hydrogen donor (which is the case for abstraction from the O-H bond). Thus, the nature of the abstracting species has a large effect on the reaction rate in solvents. They still hypothesize that the reaction of a non-polar hydrogen donor and non-polar abstracting radical will have little solvent effect, but acknowledge this is hard to test experimentally due to the high activation barrier of these reactions. Kinetic solvent effects on the addition of radicals to multiple bonds (Figure ) has mainly been investigated theoretically and has been extensively studied by the groups of Fouassier and Radom . In one such study, when various radicals were added to methyl acrylate using DFT calculations with continuum solvation, the rate of reaction in various solvents correlated well with the dipole moment of the solvents; however, it was argued that a multipole approach was still needed . Polar solvents still had a small effect on the rate if the charge transfer from the reactants to transition states, calculated using a Mulliken charge analysis , was low. Wong and Radom performed calculations using the self-consistent isodensity polarizable continuum model (SCIPCM) . In the case of radicals with saturated substituents Data from adding to alkenes with saturated substituents, addition of any solvent increases the reaction barrier. Solvent decreases the barrier in the unsaturated case. The higher the dielectric constant of the solvent, the greater this effect. Finally, Garcia et al. investigated the addition of several radicals to methyl aminoacrylate with DFT and found that for an unspecified solvent, barriers increase with solvation for electrophilic radicals (phenyl and trifluoromethyl) and decrease for nucleophilic radicals (methoxymethyl and methyl) . From these studies, it can be concluded that the chemical nature of the radical has a larger effect on the rates than the polarity of the solvents in this reaction family.