Table 1.

Effect of counter ions on the transport of racemic protonated NEA (21) after 10 h of transport time using macrocycle (R,R)-2 as a carrier.

Counter Ions	Transported Amount (%)	Optical Purity (%)
acetate	45	5
t-butyl sulfonate	42	7
chloride	42	7
p-toluenesulfonate	38	5