Proton controlled supramolecular assembly: A comparative structural study of bis(2-guanidinobenzimidazolo)nickel(II) with bis(2-guanidinobenzimidazole)nickel(II) nitrate and 2-guanidinobenzimidazole

Citation
Mm. Bishop et al., Proton controlled supramolecular assembly: A comparative structural study of bis(2-guanidinobenzimidazolo)nickel(II) with bis(2-guanidinobenzimidazole)nickel(II) nitrate and 2-guanidinobenzimidazole, SUPRAMOL CH, 13(2), 2001, pp. 293-301
Citations number
13
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Chemistry
Journal title
SUPRAMOLECULAR CHEMISTRY
ISSN journal
1061-0278 → ACNP
Volume
13
Issue
2
Year of publication
2001
Pages
293 - 301
Database
ISI
SICI code
1061-0278(2001)13:2<293:PCSAAC>2.0.ZU;2-#
Abstract
Previously studies have shown that when 2-guanidinobenzimidazole complexes with a number of transition metal ions it tautomerises so that, in contrast to the free ligand structure, no intermolecular hydrogen bonding between b ound ligands occurs. In the present study it is demonstrated that ligand de protonation to yield bis(2-guanidinobenzimidazolo)nickel(II) restores much of the original hydrogen bonding capability of the uncomplexed ligand. The structure of this neutral complex is compared to the previously reported st ructure of its diprotonated derivative, bis(Z-guanidinobenzimidazole)nickel (II) nitrate, as well as to the structure of the uncomplexed ligand. In con trast to the dicationic species, the neutral complex exists in two enantiom eric forms that assemble to form an extended supramolecular lattice, contai ning channels through its structure. The walls of the channels are made up of 'strings' of complex molecules and are held in position by hydrogen bond ing between the bound ligands and dimethyl sulfoxide (solvent) molecules as well as water molecules. Some of the solvent molecules lie within the chan nels and some outside. The hydrogen bonding motif responsible for chain for mation differs from that found in the free ligand structure.