K. Venkateswaran et al., INTRAMOLECULAR SELECTIVITY OF MUONIUM TOWARDS CHLORINATED AROMATIC-COMPOUNDS, Hyperfine interactions, 87(1-4), 1994, pp. 947-952
Muon resonance studies show that muonium atoms (Mu) in ethanol add sel
ectively to certain C-sites of aromatic compounds containing -Cl and -
OH substituents. The sites chosen seem to be those carrying the lowest
electron density. This helps to characterize Mu as a nucleophile in a
ddition reactions and, in this respect, Mu differs from ordinary H-ato
ms. The study shows no apparent inter-molecular selectivity between a
pair of aromatic solutes in an equimolar mixture, but strong intra-mol
ecular selectivity in an ether composed of those two aromatic rings. T
his difference between intra- and inter-molecular selectivity is inter
preted as kinetic in origin - arising from the 'caging effect' of the
solvent and peculiar to reactions close to the diffusion-controlled li
mit.