Dai shirotani

This paper concerns with the synthesis and the luminescence spectra of lanthanide complexes of EuIII) and/or Eu(II) or Tb(III) ions which are embedded into fibrous palygorskite and sepiolite clays in which the magnesium ion are ion exchanged with lanthanide ions. The He-Cd laser excitation photoluminescence of the present complexes without organic ligands exhibit the deferration effects. The phosphors with light harvesting ligands such as benzophenone derivatives and 1,10-phenanthroline give the fairly strong visible luminescence by UV-A light excitation with a LED black light in a light room under fluorescent lamps. Further, the temperature dependent phosphors with benzophenone derivatives exhibit the stronger luminescence with increasing the temperature over 100 degrees C.

For Delta-SAPR-8-Cs[Ln((+)-hfbc)(4)]((+)-hfbc = (+)-heptafluoro-butyryl-camphorate; Cs-Ln), the vibrational circular dichroism pattern and intensity of Cs-La, Cs-Nd, Cs-Gd, Cs-Ho, Cs-Er, Cs-Lu and Cs-Sm, Cs-Eu, Cs-Tb, Cs-Dy, Cs-Tm, Cs-Yb, respectively, are correlated with the even and the odd parity of total orbital angular momentum in the ground state terms.

The preparation of tetrakis((+)-hfbc) lanthanide(III) complexes with an encapsulated alkali metal and ammonium ions M[Ln((+)-hfbc)4] (hereafter abbreviated as M-Ln?:?(+)-hfbc, (+)-heptafluorobutyrylcamphorate; M, ammonium or benzyl ammonium ions as well as alkali metal ions) was reported and discussed. The electronic circular dichroism (CD) spectra in the intraligand p-p* transition of MLn were examined in view of the solvent effect. Here, the concentration, alkali metal, and ammonium ion dependences are compared with the solid CD, 5D0???7F0(Eu(III)) excitation spectra, circularly polarized luminescence, and vibrational circular dichroism. It has been revealed that the dodecahedral eight coordinate DD-8-M-Ln complexes in crystals are equilibrated between the diastereoselectively formed square antiprism eight coordinate SAPR-8-M-Ln and [Ln((+)-hfbc)3] in EtOH and CH3CN solutions or between the SAPR-8-M-Ln and DD-D2d(mmmm)-8-M-Ln complexes in CHCl3 solution. The observed CD couplets are found to reflect the exciton CD couplets which are useful to determine the four-bladed SAPR-(llll) absolute configuration around the lanthanide(III) ion. Chirality 24:10551062, 2012. (c) 2012 Wiley Periodicals, Inc.

For electronic circular dichroism in the 4f-4f transitions (4f-4f CD) of a series of nine tetrakis ((+)-3-heptafluorobutyrylcamphorato) Ln(III) complexes,Delta-SAPR-8-C-4(llll) Cs[Ln((+)-hfbc)(4)]center dot H2O (Cs-Ln = Cs-Pr, -Nd, -Sm, -Eu, -Dy, -Ho, -Er, -Tm, -Yb), the spectroscopic observables such as the dissymmetry factor g = Delta epsilon/epsilon values with the intensities (Delta epsilon) of the CD components and the molar absorption intensities (epsilon) in the 4f-4f transitions between the L-2S+1(J) levels are compared with each other to test the classification of the CD components in the relative order of the observables predicted in terms of the selection rule for 4f-4f transitions. The 4f-4f CD-based chiroptical spectra-structural relationship across the series of Delta-SAPR-8-C-4(llll) lanthanide(III) complexes is proposed: the signs of the 4f-4f CD or CPL in the hypersensitive transitions are related to the absolute configuration; Ln complexes with a negative CD component have the Delta-configuration around Ln(III) and vice versa.

The luminescence and circularly polarized luminescence (CPL) spectra of M-I[Eu((+)-hfbc)(4)] show a similar behavior to the exciton CD in the intraligand pi-pi* transitions when the alkali metal ions and solvents are manipulated. There is a difference in susceptibility in solvation toward the alkali metal ions but not toward the Eu(III) ion, as in the case of axially symmetric DOTA-type compounds. The remarkable CPL in the 4f-4f transitions provide much more information on the stereospecific formation of chiral Eu(111) complexes, since CPL spectroscopy is limited to luminescent species and reflects selectively toward helicity of the local structural environment around the lanthanide(III). While in comparison, exciton CD reveals the chiral structural information from the helical arrangement of the four bladed chelates. Of special importance, the observation of the highest CPL activities measured to date for lanthanide(III)-containing compounds (i.e., Eu and Sm) in solution supports the theory that the chirality of lanthanide(III) in the excited state corresponds to that in the ground state, which was derived from the exciton CD.