The Hydrolysis of Naphthalene Diimides

The hydrolyses of naphthalene diimides (NDIs) bearing aliphatic side chains with N-methylpyrrolidinium groups placed two (1) and three (5) atoms from the central core were studied. The Ka values for the first and second hydrolyses for 1 were 2.5 ± 0.2 x 105 M-1 and 2.0 ± 0.1 x 102 M-1, respectively; for 5 they were 1.4 ± 0.1 x 105 M-1 and 44 ± 2 M-1, respectively. NDI 1 hydrolyzed 6.8 times faster than did 5. The rates for the first and second hydrolyses of 1 at 100 mM hydroxide measured by stopped-flow were 17.0 ± 0.2 s-1 and 53.0 ± 0.1 x 10-2 s-1, respectively. NMR showed both the syn and anti isomers of the diamide species. Syntheses of other derivatives are reported. Overall, this study shows that the rate of hydrolysis of NDIs is increased when the cationic charge is moved closer to the NDI core