A series of Nd III and Eu III complexes containing achiral or chiral dithiocarbamato (dtc) ligands, [Ln(Xdtc)3(NN)] {Ln = Nd or Eu; X = dimethyl-(Me2), pyrrolidine-(pyr), or (S)-prolinol-(S-proOH); NN = 1,10-phenanthroline (phen) or 2,2'-bipyridine (bpy)}, were prepared and their crystal structures and spectroscopic properties, in particular the natural circular dichroism (CD) and magnetic circular dichroism (MCD), were investigated. The crystal structures of the complexes analyzed by the X-ray diffraction method showed an 8-coordinate geometry around the Ln III center with comparable structural parameters to one another and to the related complexes reported previously. These complexes exhibited similar spectral patterns in their absorption, natural CD and MCD spectra in solution. Weak but characteristic sharp f-f transition bands were observed in the absorption and MCD spectra, but no CD signals associated with these transitions were observed even in the S-proOHdtc complexes. The MCD spectral pattern of the Eu III complexes revealed a local C2v symmetry around the Ln III center in solution, in contrast to the aqua and the analogous β-diketonato Eu III complexes.

Four new homodinuclear lanthanoid(III) dithiocarbamato (RR'dtc -) complexes bridged by 2,2'bipyrimidine (bpm) of the form [{Ln(RR'dtc)3}2(µ-bpm)] {Ln = Nd or Eu; RR' = dimethyl-(Me2) or pyrrolidine-(pyr)} were prepared and their crystal structures and spectroscopic properties were characterized. Crystallographic studies revealed that all of the complexes possess a similar structural motif with an 8:8-coordination geometry, in which bpm bridges two Ln III centers in the κ 2 N 1,1' :κ 2 N 3,3' mode and three RR'dtcligands coordinate to each Ln III center.The complexes exhibited weak but relatively sharp f-f transition bands in the absorption and magnetic circular dichroism (MCD) spectra recorded in the visible region. The MCD spectral studies demonstrated the magneto-optical behavior of the complexes. The spectral features of the dithiocarbamato complexes were distinctly different from those of the β-diketonato analogues, suggesting the coordination environment around the Ln III center influences the electronic structure and spectroscopic symmetry of the complexes in solution.

This paper describes the development of a simple magnetic circular dichroism (MCD) apparatus from a wood base and neodymium magnets and its configuration in the Faraday alignment. The applicability and effectiveness of the apparatus for MCD spectra measurements have been examined. The apparatus was used by undergraduate students to conduct MCD experiments on Ni2+, Co2+, Nd3+, and Eu3+ ions in aqueous solutions. Absorption spectra of the sample solutions were also measured. The results of the MCD and absorption spectra of d–d and f–f transition were compared. The results indicate that the apparatus can be used to teach undergraduate students.

E)-N-Benzylidenepicolinohydrazide (Hbphz) was used to synthesize a series of hydrazonatobridged homodinuclear Ln III 2 dithiocarbamato (RR'dtc -) complexes of the form [{Ln(RR' dtc)2}2(µ-bphz)2] {Ln = La, Pr, Nd, Sm or Eu; RR' = dimethyl-(Me2) or pyrrolidine-(pyr)}.X-ray crystallographic studies revealed that these complexes possessed a common head-to-tail type dinuclear structural motif in which two hydrazonato ligands bridged two Ln III centers in the -1 2 N(py),O:2 2 O,N(imine) mode and two RR'dtc ligands coordinated to each Ln III center. Interestingly, while the Sm III and Eu III complexes crystallized as simple 8:8-coordinate dinuclear molecules, the lighter Ln III (i.e. La III , Pr III and Nd III ) complexes afforded in some cases 9:9-coordinate molecules, where the ninth coordination site was occupied by a solvent ethanol or methanol molecule. Even for the lighter Ln III complexes, the complexes were solved in dichloromethane or chloroform as the 8:8-coordinate dimer, as revealed by 1 H NMR spectroscopy. In the UV-visible absorption and magnetic circular dichroism (MCD) spectra of the complexes, similar spectral patterns for ligand-centered and Laporte forbidden f-f transitions were observed. The MCD spectral studies demonstrated the characteristic magnetooptical behavior of the complexes.