Linked Life Data

20922246

Source:http://linkedlifedata.com/resource/pubmed/id/20922246

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
42
pubmed:dateCreated
2010-10-20
pubmed:abstractText
The new macrocyclic ligand 1,9(4,7)-diphenanthroline-3,7,11,15-tetraazacyclohexadecaphane (L) was synthesized by a 2?:?2 reaction of 1,10-phenanthroline-4,7-dialdehyde with 1,3-diaminopropane, followed by reduction with NaBH(4). L contains two phenanthroline groups linked together by two 1,3-diaminopropane chains in such a way that the heteroaromatic nitrogen atoms point outside the ligand cavity. The ligand structure defines two pairs of identical compartments displaying a specific ability in the binding of protons (1,3-diaminopropane) and metal ions (phenanthroline). Protonation and Zn(II) coordination were studied by means of potentiometric and spectroscopic ((1)H NMR, UV-vis, fluorescence) techniques. Both protonation and Zn(II) coordination consistently affect the fluorescence emission properties of L, giving rise to enhancement or quenching of the emission, depending on the species involved. L becomes emissive upon protonation, but the formation of the highly protonated species, in particular the fully protonated [H(6)L](6+), quenches the emission. The mono- and dinuclear Zn(II) complexes of the unprotonated ligand are non-emissive, like free L, while Zn(II) binding to [HL](+) activates the emission. The most interesting aspect, however, is the chelation enhancement of quenching (CHEQ) observed upon Zn(II) binding to [H(2)L](2+) and [H(4)L](4+), being among the few examples of CHEQ effect observed for Zn(II) complexes. Hydrogen bonding between a metal coordinated water molecule and a phenanthroline group seems to be responsible for the CHEQ observed for [ZnH(2)L](4+).
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
1477-9234
pubmed:author
pubmed:issnType
Electronic
pubmed:day
14
pubmed:volume
39
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
10128-36
pubmed:meshHeading
pubmed:year
2010
pubmed:articleTitle
Binding of H+ and Zn(II) ions with a new fluorescent macrocyclic phenanthrolinophane.
pubmed:affiliation
Department of Chemistry Ugo Schiff, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, Italy.
pubmed:publicationType
Journal Article