Two new fluorescent chemosensors for metal ions have been synthesized and characterized, and their photophysical properties have been explored; they are the macrocycles 5-(2-quinolinylmethyl)-2,8-dithia-5-aza-2,6-pyridinophane (L5) and 5-(5-chloro-8-hydroxyquinolinylmethyl)-2,8-dithia-5-aza-2,6-pyridinophane (L6). Both systems have a pyridylthioether- containing 12-membered macrocycle as a binding site. The coordination properties of these two ligands toward CuII, ZnII, CdII, HgII, and PbII have been studied in MeCN/H2O (1:1 v/v) and MeCN solutions and in the solid state. The stoichiometry of the species formed at 25 °C have been determined from absorption, fluorescence, and potentiometric titrations. The complexes [CuL5](ClO4)2â1/2MeCN, [ZnL5(H2O)](ClO4)2, [HgL5(MeCN)](ClO4)2, [PbL5- (ClO4)2], [Cu3(5-Cl-8-HDQH-1)(L6H-1)2](ClO4)3â7.5H2O (HDQ ) hydroxyquinoline), and [Cu(L6)2](BF4)2â2MeNO2 have also been characterized by X-ray crystallography. A specific CHEF-type response of L5 and L6 to the presence of ZnII and CdII, respectively, has been observed at about pH 7.0 in MeCN/H2O (1:1 v/v) solutions.
Tuning the selectivity/specificity of luorescent metal ion sensors based on N2S2 pyridine-containing macrocyclic ligands by changing the fluorogenic subunit: spectrofluorimetric and metal ion binding studies
ARAGONI, MARIA CARLA;ARCA, MASSIMILIANO;CALTAGIRONE, CLAUDIA;GRETA DE FILIPPO;ISAIA, FRANCESCO;LIPPOLIS, VITO;MAMELI, MARTA;
2007-01-01
Abstract
Two new fluorescent chemosensors for metal ions have been synthesized and characterized, and their photophysical properties have been explored; they are the macrocycles 5-(2-quinolinylmethyl)-2,8-dithia-5-aza-2,6-pyridinophane (L5) and 5-(5-chloro-8-hydroxyquinolinylmethyl)-2,8-dithia-5-aza-2,6-pyridinophane (L6). Both systems have a pyridylthioether- containing 12-membered macrocycle as a binding site. The coordination properties of these two ligands toward CuII, ZnII, CdII, HgII, and PbII have been studied in MeCN/H2O (1:1 v/v) and MeCN solutions and in the solid state. The stoichiometry of the species formed at 25 °C have been determined from absorption, fluorescence, and potentiometric titrations. The complexes [CuL5](ClO4)2â1/2MeCN, [ZnL5(H2O)](ClO4)2, [HgL5(MeCN)](ClO4)2, [PbL5- (ClO4)2], [Cu3(5-Cl-8-HDQH-1)(L6H-1)2](ClO4)3â7.5H2O (HDQ ) hydroxyquinoline), and [Cu(L6)2](BF4)2â2MeNO2 have also been characterized by X-ray crystallography. A specific CHEF-type response of L5 and L6 to the presence of ZnII and CdII, respectively, has been observed at about pH 7.0 in MeCN/H2O (1:1 v/v) solutions.
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
