A new 3,5-bisporphyrinylpyridine derivative as a fluorescent ratiometric probe for zinc ions.
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.
Department of Chemistry and QOPNA, University of Aveiro, Campus de Santiago, 3810-193 Aveiro (Portugal); BIOSCOPE Group, REQUIMTE, Chemistry Department, Faculty of Science and Technology, University NOVA of Lisbon, 2829-516, Monte da Caparica (Portugal); ProteoMass Scientific Society, Madan Parque, Rua dos Inventores, 2825-182, Caparica (Portugal).
Nuno M M
NM
Moura
Cristina
C
Núñez
Sérgio M
SM
Santos
M Amparo F
MA
Faustino
José A S
JA
Cavaleiro
Filipe A
FA
Almeida Paz
M Graça P M S
MG
Neves
José Luis
JL
Capelo
Carlos
C
Lodeiro
D018360:Crystallography, X-Ray; D005456:Fluorescent Dyes / Q000138:chemical synthesis / Q000737:chemistry; D005740:Gases / Q000737:chemistry; D007477:Ions / Q000737:chemistry; D008968:Molecular Conformation; D010880:Piperidines / Q000737:chemistry; D019904:Polymethyl Methacrylate / Q000737:chemistry; D011166:Porphyrins / Q000138:chemical synthesis / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D015032:Zinc / Q000032:analysis*
C000597343:3,5-bis(5,10,15,20-tetraphenylporphyrin-2-ylmethyl)pyridine; C509964:5,10,15,20-tetraphenylporphyrin; D005456:Fluorescent Dyes; D005740:Gases; D007477:Ions; D010880:Piperidines; D011166:Porphyrins; C032727:piperidine; D019904:Polymethyl Methacrylate; D015032:Zinc
X-ray diffraction; fluorescent probes; porphyrinoids; sensors; zinc