227795-98-4Relevant academic research and scientific papers
Diaza-18-Crown-6 Ligands Containing Two Aminophenol Side Arms: New Heterobinuclear Metal Ion Receptors
Su, Ning,Bradshaw, Jerald S.,Zhang, Xian Xin,Savage, Paul B.,Krakowiak, Krzysztof E.,Izatt, Reed M.
, p. 3825 - 3829 (2007/10/03)
Three diaza-18-crown-6 ligands substituted with two aminophenol side arms were synthesized as possible heterobinuclear metal ion receptors. Bis(p-aminophenol)-substituted diaza-18-crown-6 ligand (13) was prepared by treating the diazacrown with α-bromo-4-nitro-o-cresol in the presence of N,N-diisopropylethylamine followed by reduction of the nitro groups. Bis(o-aminophenol)-substituted diaza-18-crown-6 ligands (11 and 12) were prepared in two steps by the aminomethylation of either an o-nitrophenol or o-(trifluoroacetamido)phenol followed by reduction of the nitro groups or hydrolysis of the trifluoroacetamide groups. All new bisphenol-armed diazacrown ligands were purified by ultrasonication in MeOH followed by filtration and drying. Interaction of the ligands with Na+, K+, Ag+, and Cu2+ was evaluated by a calorimetric titration technique at 25°C in MeOH. The complexes of Ag+ and Cu2+ are much more stable than those of Na+ and K+. Heterobinuclear complexes were observed for 11-Cu2+ - Na+ and 12-Cu2+-Na+ but not for 13-Cu2+-Na+ or for 12-Cu2+-Ag+.
