Chiroptical spectra of tetrakis (+)-3-heptafluorobutylrylcamphorate Ln(III) complexes with an encapsulated alkali metal ion: solution structures as revealed by chiroptical spectra

Chirality. 2012 Dec;24(12):1055-62. doi: 10.1002/chir.22097. Epub 2012 Sep 3.

Abstract

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 π-π* transition of M-Ln were examined in view of the solvent effect. Here, the concentration, alkali metal, and ammonium ion dependences are compared with the solid CD, (5)D(0)←(7)F(0) (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 CH(3) CN solutions or between the SAPR-8-M-Ln and DD-D(2d) (mmmm)-8-M-Ln complexes in CHCl(3) 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.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Camphor / chemistry*
  • Circular Dichroism
  • Lanthanoid Series Elements / chemistry*
  • Luminescent Measurements
  • Metals, Alkali / chemistry*
  • Models, Molecular
  • Molecular Conformation
  • Optical Phenomena*
  • Organometallic Compounds / chemistry*
  • Quaternary Ammonium Compounds / chemistry
  • Solutions
  • Solvents / chemistry
  • Stereoisomerism

Substances

  • Lanthanoid Series Elements
  • Metals, Alkali
  • Organometallic Compounds
  • Quaternary Ammonium Compounds
  • Solutions
  • Solvents
  • Camphor