Article In: orcid, cienciavitae
Metal complexes of a tetraazacyclophane: Solution and molecular modelling studies
Dalton Transactions
— 2003
Key information
Authors:
Published in
2003
Abstract
An alternative synthetic approach to yield the compound 2,3,5,6,8,9,11,14-octahydrobenzo[l][1,4,7,10]tetraazacyclotetradecine (bz[14]N4) is presented. The protonation constants of bz[14]N4 and the stability constants of its complexes with Ni2+, Cu2+, Zn2+, Cd2+, Pb2+ were determined in H2O at 25 °C with ionic strength 0.10 mol dm3 in KNO3 and they were compared with structurally related macrocycles cyclam (1,4,8,11-tetraazacyclotetradecane) and cyclen (1,4,7,10-tetraazacyclododecane). These studies indicate that only 1 1 (M L) species are formed in solution, and the ligand exhibits a high affinity for larger ions such as Cd2+ and Pb2+. The X-ray study of [bz[14]N4H3]3+ shows that an inclusion compound with a chloride counter-anion is formed through NHCl hydrogen bonds. Spectroscopic data in solution (electronic and NMR spectra) showed that the macrocycle adopts a planar arrangement upon metal complexation. Molecular mechanics calculations reveal that in spite of the presence of the benzene ring in the macrocyclic framework this ligand can encapsulate metal ions with different stereo-electronic sizes in square planar arrangements. Our results indicate that the presence of the benzene ring in the backbone of the bz[14]N4 confers a coordination behaviour intermediate between that of cyclam and cyclen.
Publication details
Authors in the community:
Rita Virgínia Delgado António
ist10884
Publication version
AO - Author's Original
Title of the publication container
Dalton Transactions
First page or article number
1852
Last page
1860
Issue
9
Fields of Science and Technology (FOS)
chemical-sciences - Chemical sciences
Publication language (ISO code)
eng - English
Alternative identifier (URI)
http://www.scopus.com/inward/record.url?eid=2-s2.0-1642492852&partnerID=MN8TOARS
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