Homodinuclear lanthanoid(III) dithiocarbamato complexes bridged by 2,2′-bipyrimidine: Syntheses, structures and spectroscopic properties

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. Each LnIII (NdIII or EuIII) center in the dimer is 8-coordinated by three dithiocarbamato ligands (RR′dtc−) and a 2,2′-bipyrimidine (bpm) having a κ2N1,1′:κ2N3,3′ bridging mode. Two pyrimidine rings of the bridging bpm ligand are almost planar and the mutually pseudo trans-positioned RR′dtc ligands are also co-planar to each other. However, it was found for some of the pyrrolidine dithiocarbamato (pyrdtc−) complexes, [{Ln(pyrdtc)3}2(μ-bpm)], one of the coordinated pyrdtc ligands exhibits a severe structural distortion.