Crown Complexanes. Carboxymethyl and Phosphonomethyl Derivatives of Aza-Crown Ethers

Abstract

The complexane-type chelating agents were derived from aza-crown ethers either by N-carboxymethylation or N-phosphonomethylation.The macrocyclic complexanes obtained (crown complexanes) interacted in aqueous media with various metal ions with an uncommon selectivity.The metal ions are incorporated in the crown ether ring on complexation.The importance of alkali and alkaline earth metal ions in the physiological process in the living organisms is widely recognized.2) The role of some trace transition metals in biological processes is also well known. Much efforts have been made for synthetic carriers or ionophores, which mediate a selective transport of metal ions through a lipophilic barrier. However, rather little has been explored for the compounds which selectively bind alkali or alkaline earth metals and remain essentially in aqueous media. 4) The major family of traditional chelating agents has the metal selectivity which follows either Irving-Williams type stability order or a HSAB (hard and soft acids and bases) concept. The chelating agents which deviate from this classification are rare. Such uncommon complexing agents should be highly useful as reagents in studying the physiochemical processes in the living cells which take place under a subtle balance of metal ion concentration. 5)In the present communication, the synthesis and the properties of the macrocyclic complexanes 1 -5 ("crown complexanes" 1) ) are described.These compounds show a much higher affinity to alkali and alkaline earth metals and some unique selectivity among transition metals as compared with the traditional chelating agents. The crown complexanes were synthesized either by carboxymethylation or phosphonomethylation of the parent aza-crown ethers according to the ordinary synthetic procedures.The isolation and purification were achieved by an ion exchange column treatment followed by recrystallization. The details will be given in a separate communication. 6) The compounds were readily soluble in water, 1 (n = 1) 2 (n = 2) 3

(1,4,10,13-Tetraoxa-7,16-diazacyclooctadecane-7,16-diacetato)cobalt(II)

“…During investigations into coordination polymers involving the ligand 1,4,10,13-tetraoxa-7,16-diazacyclooctadecane-7,16diacetic acid, the title compound, (I), was synthesized. This complex has been prepared previously for studies of formation constants (Tazaki et al, 1982), but has not previously been structurally characterized.…”

Crown Ether Pillared and Functionalized Layered Zirconium Phosphonates: A New Strategy to Synthesize Novel Ion Selective Materials

“…One of the noted characteristics of these compounds is their predictable structure skeletons. They were converted to phosphonic acids by a Mannich type reaction, 18 from which a series of bridged and unbridged zirconium phosphonates were synthesized. 17 In this paper, we report our efforts to incorporate crown ethers onto zirconium phosphonate layers.…”

“…The crown ether precusors used here are 1-aza-15-crown-5 and 1,4,10,13-tetraoxa-7,16-diazacyclooctadecane. They were converted to phosphonic acids by a Mannich type reaction, from which a series of bridged and unbridged zirconium phosphonates were synthesized. Kijima 19 recently reported incorporating the macrocyclic species into the α- and γ-zirconium phosphate by intercalation.…”

Cation Effects on Solvents, Ligands, and Nucleophiles

“…Diaza-BiBLEs 4,13-Diaza-18-crown-6 derivatives (24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35)(36)(37)(38)(39)(40)(41)(42) can be prepared by using a unique, single-step reaction of primary amines with triethylene glycol diiodide (42):…”