Ditopic binding of perchlorate anion to hexaazamacrocyclic hosts.

Synthesis L1. Diethylenetriamine (1.00 g, 9.70 mmol) and 2,5-thiophenedicarboxaldehyde (1.35 g, 9.70 mmol) were separately dissolved in CH3OH (200 cm). Both solutions were added simultaneously dropwise over 4 h to a stirred CH3OH (400 cm) at 0° C. The mixture was kept at room temperature under stirring for another 24 h, after which the solvent was evaporated. The resulting Schiff base was reduced to amine with NaBH4 (1.73 g, 45.7 mmol) in CH3OH (100 cm) at room temperature for 12 h. The solvent was evaporated under reduced pressure and the residue was dissolved in water ((100 cm). The aqueous phase was extracted by CH2Cl2 (3x100 cm). The organic layers were combined and dried with MgSO4. The product was purified by column chromatography on neutral Al2O3 using an eluent of CH2Cl2 containing 2% CH3OH to give the hexaazamacrocycle L1 as a white powder. Yield 1.23 g, 65%. Found: C, 56.6; H, 8.2; N, 20.1. C20H34N6S2 requires C, 56.8; H, 8.1; N, 19.9. H NMR (300 MHz, CDCl3, TMS): δ 6.73 (s, 4H, ArH), 3.87 (s, 8H, ArCH2), 3.77 (t, 8H, CH2), 2.72 (t, 8H, CH2).