A mechanistic study on unexpected and solvent-based pH-tuneable role of benzylic pendant side-arm on N2O2-donor naphthodiaza-crown macrocyclic ligand as a sensitive fluorogenic chemosensor for Al3+ in aqueous solution: x-ray, NMR, photophysical, and computational studies

Bahram Ghanbari, Mahsa Mahdavian, Reza Kia, Maciej Kubicki, Paul R Raithby

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Abstract

Herein, we describe for the first time synthesis, characterization, chemosenor behavior, and mechanism of metal ion-ligand interaction of two novel side-armed naphthodiaza-crown macrocycles (L1 and L2) by employing of IR, 1H and 13C NMR, UV–vis, fluorescence spectroscopy, CHN microanalysis and single crystal X-ray diffraction. Preliminary fluorescence studies in ethanol as solvent revealed that the metal ion recognition by L1 was strongly different from L2 suggesting the importance of the number of benzylic side-arms on the extent of the interaction with Mn+. For instance employing fluorescence titration in ethanol showed binding constant values 105 M−1 and 2.6×106 M−1 for L1/Al3+ and L2/Al3+, respectively. Such metal ion selectivity by L2, however, was sharply improved in aqueous media (1:1 v/v ethanol/water) in comparison with L1. The selective complex formation of L2 with Al3+ supported very low limit of detections, i.e. 5×10−7 and 7×10−6 M in ethanol and aqueous medium, respectively. Single crystal X-ray diffraction analysis (in solid) as well as 1H NMR spectroscopy in acidic DMSO-d6 solvent revealed that unparalleled direction of the electron lone pairs on the donor atoms of L2 could not let Al3+ cation to be coordinated simultaneously by both nitrogen-donor groups on the macrocycle ring. The coordination of Al3+ with both of those nitrogen donors on L2, however, was evident from the 1H NMR spectra of L2/Al3+ where the solvent was DMSO-d6.
LanguageEnglish
Pages258-266
JournalJournal of Luminescence
Volume188
Early online date25 Apr 2017
DOIs
StatusPublished - Aug 2017

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Crowns
ethyl alcohol
Ethanol
Nuclear magnetic resonance
X-Rays
Ligands
aqueous solutions
Metal ions
X rays
metal ions
nuclear magnetic resonance
ligands
Metals
Ions
Dimethyl Sulfoxide
X-Ray Diffraction
fluorescence
x rays
Nitrogen
Fluorescence

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title = "A mechanistic study on unexpected and solvent-based pH-tuneable role of benzylic pendant side-arm on N2O2-donor naphthodiaza-crown macrocyclic ligand as a sensitive fluorogenic chemosensor for Al3+ in aqueous solution: x-ray, NMR, photophysical, and computational studies",
abstract = "Herein, we describe for the first time synthesis, characterization, chemosenor behavior, and mechanism of metal ion-ligand interaction of two novel side-armed naphthodiaza-crown macrocycles (L1 and L2) by employing of IR, 1H and 13C NMR, UV–vis, fluorescence spectroscopy, CHN microanalysis and single crystal X-ray diffraction. Preliminary fluorescence studies in ethanol as solvent revealed that the metal ion recognition by L1 was strongly different from L2 suggesting the importance of the number of benzylic side-arms on the extent of the interaction with Mn+. For instance employing fluorescence titration in ethanol showed binding constant values 105 M−1 and 2.6×106 M−1 for L1/Al3+ and L2/Al3+, respectively. Such metal ion selectivity by L2, however, was sharply improved in aqueous media (1:1 v/v ethanol/water) in comparison with L1. The selective complex formation of L2 with Al3+ supported very low limit of detections, i.e. 5×10−7 and 7×10−6 M in ethanol and aqueous medium, respectively. Single crystal X-ray diffraction analysis (in solid) as well as 1H NMR spectroscopy in acidic DMSO-d6 solvent revealed that unparalleled direction of the electron lone pairs on the donor atoms of L2 could not let Al3+ cation to be coordinated simultaneously by both nitrogen-donor groups on the macrocycle ring. The coordination of Al3+ with both of those nitrogen donors on L2, however, was evident from the 1H NMR spectra of L2/Al3+ where the solvent was DMSO-d6.",
author = "Bahram Ghanbari and Mahsa Mahdavian and Reza Kia and Maciej Kubicki and Raithby, {Paul R}",
year = "2017",
month = "8",
doi = "10.1016/j.jlumin.2017.04.041",
language = "English",
volume = "188",
pages = "258--266",
journal = "Journal of Luminescence",
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TY - JOUR

T1 - A mechanistic study on unexpected and solvent-based pH-tuneable role of benzylic pendant side-arm on N2O2-donor naphthodiaza-crown macrocyclic ligand as a sensitive fluorogenic chemosensor for Al3+ in aqueous solution

T2 - Journal of Luminescence

AU - Ghanbari, Bahram

AU - Mahdavian, Mahsa

AU - Kia, Reza

AU - Kubicki, Maciej

AU - Raithby, Paul R

PY - 2017/8

Y1 - 2017/8

N2 - Herein, we describe for the first time synthesis, characterization, chemosenor behavior, and mechanism of metal ion-ligand interaction of two novel side-armed naphthodiaza-crown macrocycles (L1 and L2) by employing of IR, 1H and 13C NMR, UV–vis, fluorescence spectroscopy, CHN microanalysis and single crystal X-ray diffraction. Preliminary fluorescence studies in ethanol as solvent revealed that the metal ion recognition by L1 was strongly different from L2 suggesting the importance of the number of benzylic side-arms on the extent of the interaction with Mn+. For instance employing fluorescence titration in ethanol showed binding constant values 105 M−1 and 2.6×106 M−1 for L1/Al3+ and L2/Al3+, respectively. Such metal ion selectivity by L2, however, was sharply improved in aqueous media (1:1 v/v ethanol/water) in comparison with L1. The selective complex formation of L2 with Al3+ supported very low limit of detections, i.e. 5×10−7 and 7×10−6 M in ethanol and aqueous medium, respectively. Single crystal X-ray diffraction analysis (in solid) as well as 1H NMR spectroscopy in acidic DMSO-d6 solvent revealed that unparalleled direction of the electron lone pairs on the donor atoms of L2 could not let Al3+ cation to be coordinated simultaneously by both nitrogen-donor groups on the macrocycle ring. The coordination of Al3+ with both of those nitrogen donors on L2, however, was evident from the 1H NMR spectra of L2/Al3+ where the solvent was DMSO-d6.

AB - Herein, we describe for the first time synthesis, characterization, chemosenor behavior, and mechanism of metal ion-ligand interaction of two novel side-armed naphthodiaza-crown macrocycles (L1 and L2) by employing of IR, 1H and 13C NMR, UV–vis, fluorescence spectroscopy, CHN microanalysis and single crystal X-ray diffraction. Preliminary fluorescence studies in ethanol as solvent revealed that the metal ion recognition by L1 was strongly different from L2 suggesting the importance of the number of benzylic side-arms on the extent of the interaction with Mn+. For instance employing fluorescence titration in ethanol showed binding constant values 105 M−1 and 2.6×106 M−1 for L1/Al3+ and L2/Al3+, respectively. Such metal ion selectivity by L2, however, was sharply improved in aqueous media (1:1 v/v ethanol/water) in comparison with L1. The selective complex formation of L2 with Al3+ supported very low limit of detections, i.e. 5×10−7 and 7×10−6 M in ethanol and aqueous medium, respectively. Single crystal X-ray diffraction analysis (in solid) as well as 1H NMR spectroscopy in acidic DMSO-d6 solvent revealed that unparalleled direction of the electron lone pairs on the donor atoms of L2 could not let Al3+ cation to be coordinated simultaneously by both nitrogen-donor groups on the macrocycle ring. The coordination of Al3+ with both of those nitrogen donors on L2, however, was evident from the 1H NMR spectra of L2/Al3+ where the solvent was DMSO-d6.

UR - https://doi.org/10.1016/j.jlumin.2017.04.041

UR - https://doi.org/10.1016/j.jlumin.2017.04.041

U2 - 10.1016/j.jlumin.2017.04.041

DO - 10.1016/j.jlumin.2017.04.041

M3 - Article

VL - 188

SP - 258

EP - 266

JO - Journal of Luminescence

JF - Journal of Luminescence

SN - 0022-2313

ER -