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A New 3,5‐Bisporphyrinylpyridine Derivative as a Fluorescent Ratiometric Probe for Zinc Ions
Author(s) -
Moura Nuno M. M.,
Núñez Cristina,
Santos Sérgio M.,
Faustino M. Amparo F.,
Cavaleiro José A. S.,
Almeida Paz Filipe A.,
Neves M. Graça P. M. S.,
Capelo José Luis,
Lodeiro Carlos
Publication year - 2014
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201402270
Subject(s) - chemistry , zinc , pyridine , metal ions in aqueous solution , ligand (biochemistry) , metal , fluorescence , porphyrin , stoichiometry , derivative (finance) , analytical chemistry (journal) , photochemistry , organic chemistry , economics , biochemistry , physics , receptor , quantum mechanics , financial economics
A new 3,5‐disubstituted pyridine with two porphyrin moieties was prepared through an efficient synthetic approach involving 2‐formyl‐5,10,15,20‐tetraphenylporphyrin ( 1 ), piperidine, and catalytic amounts of [La(OTf) 3 ]. 3,5‐Bis(5,10,15,20‐tetraphenylporphyrin‐2‐ylmethyl)pyridine ( 2 ) was fully characterized and its sensing ability towards Zn 2+ , Cu 2+ , Hg 2+ , Cd 2+ , and Ag + was evaluated in solution by absorption and fluorescence spectroscopy and in gas phase by using matrix‐assisted laser desorption/ionization (MALDI)‐TOF mass spectrometry. Strong changes in the ground and excited state were detected in the case of the soft metal ions Zn 2+ , Cd 2+ , Hg 2+ , and Cu 2+ . A three‐metal‐per‐ligand molar ratio was obtained in all cases and a significant ratiometric behavior was observed in the presence of Zn 2+ with the appearance of a new band at 608 nm, which can be assigned to a metal‐to‐ligand charge transfer. The system was able to quantify 79 ppb of Zn 2+ and the theoretical calculations are in accordance with the stoichiometry observed in solution. The gas‐phase sensorial ability of compound 2 towards all metal ions was confirmed by using MALDI‐TOF MS and in solid state by using polymeric films of polymethylmethacrylate (PMMA) doped with ligand 2 . The results showed that compound 2 can be analytically used to develop new colorimetric molecular devices that are able to discriminate between Hg 2+ and Zn 2+ in solid phase. The crystal structure of Zn II complex of 3,5‐bisporphyrinylpyridine was unequivocally elucidated by using single‐crystal X‐ray diffraction studies.