Synthesis, Characterization and Studies on the Thermal Stability of Bis(Indenyl)-Praseodymium and Neodymium Complexes with a Ln-S Bond: (C₉H₇)₂Lnsr(Thf)

Abstract

Four new bis(indeny1)lanthanide thiolate complexes, (C₉H₇)₂LnSR(THF) [Ln[dbnd]Nd, R=2-benzoxazolyl (I), 2-(I-methyl)imidazolyl (n) and 2-pyrimidinyl (III); Ln = Pr, R = 2-pyrimidinyl (IV)], have been first synthesized by the reaction of (C₉H₇)₃Ln with equimolar amounts of thiols. These complexes were Characterized by elemental analyses, IR spectra and MS spectra, indicating that they are present as monomer structures with coordinated THF. The thermal stability of complex I has been studied by the temperature dependence of ESR spectra and TG and DTA measurements. The ESR spectra show that, at low temperature, the g-value (2.0038) which is close to the free electron spin value (g_e, = 2.0032) may be assigned to the 4f Nd³ ion. When the temperature is higher than 400 K, the g-value, line width (AHpp) and relative intensity changed, probably due to the paramagnetism of decomposed organic ligand radicals.