Co-ordination chemistry and molecular mechanics study of the magnesium(II) and calcium(II) complexes of trisubstituted 1,4,7-triazacyclononane derivatives
Novel azamacrocycles having amide-functionalized arm groups have been shown to mediate selective and efficient transport of ‘hard’ alkali and alkalineearthmetalcations via three-dimensional complexations, while the parent azamacrocycles favour ‘soft’ metalcations.
A variety of multiarmed macrocyclic polyamines were prepared as a new type of metal carrier, in which amide-, ester-, nitrile-, and ketone-functionalized arms were attached as secondary donor sites. Extraction and C-13 NMR binding experiments revealed that their cation-binding behavior was largely dependent on the nature of the arm donor group as well as the size of the parent polyamine ring. In particular, introduction of an amide-functionalized arm into a suitable polyamine ring significantly enhanced binding ability toward "hard" metal cations, while the parent polyamine ring weakly bound these metal cations. Their unique cation-binding properties offered an effective membrane transport of hard metal cations. Since the cation-binding and -transport profiles of the new multiarmed macrocyclic polyamines differed greatly from those observed with conventional polyamines and related macrocycles, the present study provides a new possibility for designing a novel, macrocyclic polyamine type of synthetic carrier.
TSUKUBE, HIROSHI;ADACHI, HAYAMITSU;MOROSAWA, SHIRO, J. CHEM. SOC. PERKIN TRANS. PT 1,(1989) N, C. 1537-1538