Template synthesis of helicates of a [2 + 2] tetraimine macrocycle: crystal structure of the lead(II) perchlorate complex

Fenton, David E. and Matthews, Ray W. and McPartlin, Mary and Murphy, Brian P. and Scowen, Ian J. and Tasker, Peter A. (1996) Template synthesis of helicates of a [2 + 2] tetraimine macrocycle: crystal structure of the lead(II) perchlorate complex. Journal of the Chemical Society, Dalton Trans. (16). pp. 3421-3427. ISSN 1477-9226

Full content URL: http://dx.doi.org/10.1039/DT9960003421

Full text not available from this repository.

Item Type:Article
Item Status:Live Archive

Abstract

The Schiff-base condensation of ,prime or minute-bis(2-aminophenoxy)--xylene and pyridine-2{,}6-dicarbaldehyde produced mononuclear complexes of the same 2 + 2 cyclocondensation product L in the presence of divalent metal ions ranging in size from Mn to Ba. The origin of the apparent insensitivity of the synthesis to the metal-ion size lies in the ability of the resulting 34-membered macrocycle to adopt either of two distinct co-ordination modes featuring double helical configurations stabilised by intramolecular small pi-small pi interactions. The crystal structure of PbLClOmiddle dot4MeCN trigonal{,} space group 3 with combining macron]1, == 20.557(3), = 23.843(3)A, = 0.0499, prime or minute= 0.0440 shows the metal ion co-ordinated by the NO donor set of the macrocycle within a fulldouble helical ligand array stabilised by five separate aromatic small pi-small pi interactions. Proton NMR studies of the diamagnetic complexes of L{,} assisted by detailed assignments of aromatic subspectra{,} provided evidence for retention of molecular helicity in solution; an interesting example of -spin decoupling of Pb is noted in the field-dependent spectra of PbLClO in CDCN.

Keywords:Chemistry
Subjects:F Physical Sciences > F100 Chemistry
Divisions:College of Science > School of Chemistry
ID Code:13267
Deposited On:19 Mar 2014 17:56

Repository Staff Only: item control page