Phenanthroline-Derived Ratiometric Chemosensor for Ureas

Abstract

The syntheses of 1,10-phenanthroline fluorophore-based chemosensor 7 and its truncated analog 9 are reported. Interactions of these compounds with urea, thiourea, 1,3-dimethylurea, tetrahydropyrimidin-2(1H)-one, imidazolidin-2-one, and selected uronium salts were assessed by three-dimensional excitation-emission spectroscopy, UV-vis absorbance, and fluorescence titrations. Chemosensor 7 was found to be capable of distinguishing between neutral ureas and their salts, by producing a different optical response for each type of compounds. The complexation of urea by 7 was also studied by selective-NOE 1H NMR, 13C NMR (using 13C-labeled guest), and MALDI-TOF mass spectrometry. In addition, we performed DFT calculations (B3LYP 3-21g** level) for structures of complexes of 7 with urea, imidazolidin-2-one, and tetrahydropyrimidin-2(1H)-one. Development of chemosensor 7-type compounds in conjunction with differential excitation-emission spectroscopy represents an important step toward the development of novel tools for ureas and their salts analysis.

Selective Detection of Neurotoxin by Photoluminescent Peptide Nanotubes

“…We speculate that the PL quenching originates from a change in the photophysical property of photosensitizers incorporated in FF nanotubes. As shown in Figures S2 and S3 of the SI, the phosphorescence peaks of SA and PHEN were reduced substantially only when they were exposed to paraoxon, which is attributed to the transition‐state change of the photo­sensitizer molecules (i.e., SA or PHEN) by the nitro functional group in paraoxon from strongly emissive π−π* states to poorly emissive n–π* states, according to the literature 18, 19. The change in the photosensitizer transition state should prevent the transfer of excited electrons from FF nanotubes to lanthanide ions (i.e., Tb or Eu) via photosensitizers because the electron relay in the photoluminescent FF nanotubes occurs through the cascaded energy‐transfer mechanism 15…”

Structural and spectroscopic characterization and DFT studies of 2-amino-1,10-phenanthrolin-1-ium chloride

“…The slight deviations between the experimentally observed and the theoretically calculated amino group frequencies may be attributed to intermolecular hydrogen bond formation of the electron donating amino group. The hydrogen bonding facility of the amino group in the 1,10phenantroline ring system is of great interest in developing of supramolecular receptors for binding urea [26] and biological system for the recognition of a cytosine bulge and a cytosinecytosine mismatch [29]. The cryptand-like receptors having ammonium groups are early known first type of hosts for binding halide anions [68,69].…”

“…We have an ongoing interest in the synthesis of azabridged bis-1,10-phenanthroline derivatives [10][11][12], mainly due to their significant biological activity of the corresponding metal complexes in which the planar and also rigid structure of 1,10-phenanthroline (phen) can either intercalate or bind to the grooves of DNA or RNA [13][14][15][16][17][18][19][20]. Therefore, the design and synthesis of new derivatives of phen with extended properties have gained a significant attention by many researchers [21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36]. We have previously reported an alternative strategy to synthesize a series of phen derivatives [37].…”

Synthesis, structures, photophysical properties, and catalytic characteristics of 2,9‐dimesityl‐1,10‐phenanthroline (dmesp) transition metal complexes

“…The di‐substituted 1,10‐phenanthroline structural motif has also been found in a number of isolated natural products with anticancer efficacy and in self‐assembling metal–organic systems . It is important to note that the ability to chelate metal ions also enables the utilization of phenanthroline complexes in analytical applications such as electrochemical, fluorometric, and bioorganic sensors . Many metal complexes of phenanthroline and closely related ligands have also found applications in catalytic processes such as intramolecular C–C coupling, transfer hydrogenation of ketones and nitriles, acyloxyalkylation of styrene derivatives, selective nitrene transfer, asymmetric aldol reactions, and in the synthesis of metal–organic frameworks for tandem catalytic C–H activation reactions .…”