6533b7dcfe1ef96bd1271f40
RESEARCH PRODUCT
Proton and metal binding by cyclen-based highly rigid cryptands.
Andrea BenciniCarla BazzicalupiBarbara ValtancoliI. MateraFranck DenatSamuele CiattiniPauline DésogèreChristine Gozesubject
Inorganic ChemistryCrystallographychemistry.chemical_compoundAqueous solutionCyclenLigandHydrogen bondChemistryInorganic chemistryCryptandPotentiometric titrationMoietyProtonationdescription
The basicity properties of the two cryptands L1 and L2, featuring, respectively, a dibenzofuran or a diphenyl ether moiety bridging the 1,7 positions of a 1,4,7,10-tetraazacyclododecane macrocycle (cyclen) have been studied by means of potentiometric, UV-vis and fluorescence emission measurements. Both ligands show a high basicity in the first protonation step, the first basicity constant of L1 being too high to be measured in aqueous solution. The crystal structure of {[HL1]L1}(+) shows that the NH(2)(+) group is involved in an intramolecular hydrogen bonding network, which justifies the observed high basicity in solution. (1)H, (13)C NMR, UV-vis and fluorescence emission measurements show that, among first row divalent metal cations, both L1 and L2 selectively bind in acetonitrile Cu(II) and Zn(II), which are encapsulated within the ligand cavities. Zn(II) coordination is accompanied by a remarkable increase of the fluorescence emission of the ligands, pointing out that the molecular architecture displayed by L1 and L2 can be used to develop new OFF/ON chemosensors for this metal cation.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2010-11-06 | Dalton transactions (Cambridge, England : 2003) |