Synthesis of 1,8-anthraquinone functionalized aza 18/20-crown-5 macrocycles and their chromogenic ion-pair recognition of hydroxides in DMSO

Two N 3 O 3 macrocyclic compounds with rigid chromogenic 1,8-dihydroxylenanthraquione and flexible diethylenetriamine/dipropenetriamine (L1 and L2), were synthesized and characterized. L1/L2 can interact with alkaline, alkaline-earth, as well as Zn 2+ , Pb 2+ , and Al 3+ chloride/perchloride evidenced by their DPV change and 1 H NMR spectra. Unexpectedly, both L1 and L2 can show chromogenic response to Na + , K + , and TBA + hydroxide (but not LiOH). Large cavity L2 can show chromic response to Ca(OH) 2 and Ba(OH) 2 , but L1 can only respond to Ca(OH) 2 in DMSO. L1 and L2 form 1:1 and 2:1 (Host:Guest) complex respectively with NaCl, NaOH, TBAOH in DMF/DMSO. Both hosts bind smaller Zn 2+ and Al 3+ in 2:1 in DMSO. L2 can form L2·TBAOH greenish yellow complex that gradually transformed to red L2 2 ·TBAOH in two steps in DMSO. Different from other macrocycles, L1 and L2 are ion-pair hosts that recognize cation and OH − via carbonyl groups.