title: Lanthanide(III) complexes of bis-semicarbazone and bis-imine-substituted phenanthroline ligands: solid-state structures, photophysical properties, and anion sensing.
abstract: Phenanthroline-based hexadentate ligands L(1) and L(2) bearing two achiral semicarbazone or two chiral imine moieties as well as the respective mononuclear complexes incorporating various lanthanide ions, such as La(III), Eu(III), Tb(III), Lu(III), and Y(III) metal ions, were synthesized, and the crystal structures of [ML(1)Cl(3)] (M=La(III), Eu(III), Tb(III), Lu(III), or Y(III)) complexes were determined. Solvent or water molecules act as coligands for the rare-earth metals in addition to halide anions. The big Ln(III) ion exhibits a coordination number (CN) of 10, whereas the corresponding Eu(III), Tb(III), Lu(III), and Y(III) centers with smaller ionic radii show CN=9. Complexes of L(2), namely [ML(2)Cl(3)] (M=Eu(III), Tb(III), Lu(III), or Y(III)) ions could also be prepared. Only the complex of Eu(III) showed red luminescence, whereas all the others were nonluminescent. The emission properties of the Eu derivative can be applied as a photophysical signal for sensing various anions. The addition of phosphate anions leads to a unique change in the luminescence behavior. As a case study, the quenching behavior of adenosine-5'-triphosphate (ATP) was investigated at physiological pH value in an aqueous solvent. A specificity of the sensor for ATP relative to adenosine-5'-diphosphate (ADP) and adenosine-5'-monophosphate (AMP) was found. (31)P NMR spectroscopic studies revealed the formation of a [EuL(2)(ATP)] coordination species.
authors.affiliation: Analytical Science Division, Central Salt and Marine Chemicals Research Institute, Bhavnagar, Gujarat, India.
authors.forename: Sandeep
authors.initials: S
authors.lastname: Nadella
authors.forename: Paulraj M
authors.initials: PM
authors.lastname: Selvakumar
authors.forename: Eringathodi
authors.initials: E
authors.lastname: Suresh
authors.forename: Palani S
authors.initials: PS
authors.lastname: Subramanian
authors.forename: Markus
authors.initials: M
authors.lastname: Albrecht
authors.forename: Michael
authors.initials: M
authors.lastname: Giese
authors.forename: Roland
authors.initials: R
authors.lastname: Fröhlich
mesh_terms: D000244:Adenosine Diphosphate / Q000032:analysis; D000249:Adenosine Monophosphate / Q000032:analysis; D000255:Adenosine Triphosphate / Q000032:analysis; D000838:Anions / Q000032:analysis*; D002942:Circular Dichroism; D018360:Crystallography, X-Ray; D007097:Imines / Q000737:chemistry*; D007811:Lanthanum / Q000737:chemistry*; D008024:Ligands; D049449:Luminescence; D008163:Luminescent Measurements; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D044367:Phase Transition; D010618:Phenanthrolines / Q000737:chemistry*; D012664:Semicarbazones / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D000838:Anions; D007097:Imines; D008024:Ligands; D009942:Organometallic Compounds; D010618:Phenanthrolines; D012664:Semicarbazones; D000249:Adenosine Monophosphate; D000244:Adenosine Diphosphate; D007811:Lanthanum; D000255:Adenosine Triphosphate