Synthesis and coordination properties of an azamacrocyclic Zn(II) chemosensor containing pendent methylnaphthyl groups.
The synthesis of a polyazamacrocycle constituted by two diethylenetriamine bridges functionalized at their central nitrogen with naphth-2-ylmethyl units and interconnected through 2,6-dimethylpyridine spacers (L1) is reported. The protonation behaviour of the new macrocycle in water and in water-ethanol 70/30 v/v mixed solvent has been examined by means of pH-metric, UV-Vis and steady-state fluorescence techniques. The fluorescence emission is slightly quenched following the deprotonation of the central tertiary amines and more deeply quenched upon deprotonation of the secondary amino groups. pH-Metric titrations show that in water-ethanol 70/30 v/v L1 forms stable mononuclear complexes with the divalent transition and post-transition metal ions Mn2+, Fe2+, Co2+, Cu2+, Zn2+, Cd2+, Hg2+ and Pb2+. In the case of Cu2+, Zn2+, Hg2+ and Pb2+, formation of binuclear complexes has also been observed. Steady-state fluorescence emission studies show that while interaction with Cu2+ leads to quenching of the fluorescence emission above pH = 2, interaction with Zn2+, Cd2+, Hg2+ and Pb2+ give rise to enhancements of the fluorescence above pH ca. 5, which is particularly noticeable in the case of Zn2+.
Alarcón
Javier
J
Departament de Química Inorgànica, Facultat de Química, Universitat de València, Burjassot, Spain. javier.alarcon@uv.es
Albelda
M Teresa
MT
Belda
Raquel
R
Clares
M Paz
MP
Delgado-Pinar
Estefanía
E
Frías
Juan C
JC
García-España
Enrique
E
González
Jorge
J
Soriano
Conxa
C
D001372:Aza Compounds / Q000737:chemistry*; D002623:Chemistry Techniques, Analytical / Q000295:instrumentation*; D005453:Fluorescence; D006863:Hydrogen-Ion Concentration; D008024:Ligands; D047028:Macrocyclic Compounds / Q000737:chemistry*; D009281:Naphthalenes / Q000737:chemistry*; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D055668:Photochemical Processes; D011522:Protons; D013696:Temperature; D028561:Transition Elements / Q000737:chemistry; D015032:Zinc / Q000737:chemistry*
D001372:Aza Compounds; D008024:Ligands; D047028:Macrocyclic Compounds; D009281:Naphthalenes; D009942:Organometallic Compounds; D011522:Protons; D028561:Transition Elements; C031721:naphthalene; D015032:Zinc