Diaza-l8-Crown-6 Ligands Containing Two Aminophenol Side Arms: New Heterobinuclear Metal Ion Receptors

摘要

Three diaza-18-crown-6 ligands substituted with two each of 5-amino- 2-hydroxybenzyl (1), 3-amino-5-chloro-2-hydroxybenzyl (2), or 3-amino-2-hydroxy- 5-methylbenzyl (3) units (see Figure 1) were prepared as reported in our Technical Report No. 2 of August 13, 1998. Interaction of the ligands with Na+, K+, Ag+, and Cu2+ was evaluated by a calorimetric titration technique and the results are shown in Table 1. Heterobinuclear complexes were observed for complexes 2-Cu2+ -Na+ and 3-Cu2+ -Na+ with log K values of 1.86 and 1.41, respectively (see Table 1). These binuclear complexes are possible since the Cu2+ ion can interact with the neighboring amino and hydroxy groups of the two appended benzene rings leaving the macroring cavity free for Na+. As expected, Cu2+ -1, with the amino and hydroxy groups para to each other which does not allow a stable coordination array for Cu2+, did not form a binuclear complex with Na+. Possible structures for 2-Cu2+ -Na+, 3-Cu2+ -Na+, and 1-Cu2+ are shown in Figure 1.