Crown ether-lanthanide complexes studied by CPL and TL. I. Solution stoichiometry of europium and terbium nitrate complexes of (2r,3r,11r,12r)-2,3,11,12-tetramethyl-18-crown-6

Technical Report · Tue Jan 01 04:00:00 EST 1985

OSTI ID:6207288

Metcalf, D H; Ghirardelli, R G; Palmer, R A

As part of an extensive study of the use of circularly polarized luminescence (CPL) and total luminescence (TL) in probing crown etherlanthanide interactions in nonaqueous solvents, we describe here the results of an anion-exchange experiment designed to elucidate the solution stoichiometry of a chiral crown ether-lanthanide nitrate complex in trifluoroethanol (TFE). The CPL experiment measures the differential emission of left and right circularly polarized light by a chiral luminophore when it is excited with unpolarized light. CPL is sensitive to solutions structure when a (achiral) luminosphore gains chirality through association with a chiral ligand. For lanthanides, CPL is much more easily measured than CD because of the inherent sensitivity of emission measurement and the weakness of f-f transitions in absorption. Although all lanthanides are capable of exhibiting CPL in chiral crystals, only europiym (III) and terbium(III) exhibit significant luminescence in solution, and thus solution CPL studies of lanthanides are normally limited to these ions. This study shows the usefulness of CPL and TL measurements in conjunction with NMR in characterizing subtle aspects of the solution behavior of crown-lanthanide systems that otherwise would be difficult to study.

• Research Organization: Duke Univ., Durham, NC (USA). Paul M. Gross Chemical Lab.
• OSTI ID: 6207288
• Report Number(s): AD-A-159894/5/XAB
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ABSORPTION
CHARGED PARTICLES
CRYSTALS
ELEMENTS
EMISSION
ETHERS
EUROPIUM
ION EXCHANGE
IONS
LIGANDS
LUMINESCENCE
MAGNETIC RESONANCE
METALS
NITRATES
NITROGEN COMPOUNDS
NUCLEAR MAGNETIC RESONANCE
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
ORGANIC SOLVENTS
OXYGEN COMPOUNDS
POLARIZATION
RARE EARTHS
RESONANCE
SALTS
SOLVENTS
STOICHIOMETRY
TERBIUM