Structural Trends in 3 d-4 f Systems. Part II: Ln(NO3)(3)-Cu(NO3)(2)-2,2-biyridine/5,5-dimethyl-2,2-bipyridine (Ln=La-Nd, Sm-Lu)

摘要

A series of thirty six complexes obtained from acetonitrile solutions of Cu(NO3)(2), Ln(NO3)(3) and 2,2-biyridine or 5,5-dimethyl-2,2-bipyridine (Ln=La-Yb excluding Pm) have been characterized. The crystals may be grouped into six types: Type-I, Cu(bpy)(3)La(NO3)(5)(OH2); Type-II, Cu(bpy)(3)Ln(NO3)(5)(OH2) . 2CH(3)CN (Ln=Ce, Pr); Type-IIa, Cu(5,5-dmbpy)(3)Ln(NO3)(5)(OH2) . 2CH(3)CN (Ln=La, Ce); Type-III, Cu(bpy)(3)Ln(NO3)(5) (Ln=Nd, Sm-Lu); Type-IIIa Cu(5,5-dmbpy)(3)Ln(NO3)(5) (Ln=Pr, Nd, Sm-Lu); Type-IV, Cu(5,5-dmbpy)(2)(NO3)(2)Ln(NO3)(5)(OH2).CH3CN Ln=La-Nd, Sm-Tb). The coordination numbers of the nitrato and aquonitrato lanthanide anions are 10 and 11, respectively. The tris-chelates in Types I, II and IIIa undergo static Jahn-Teller distortion while Types IIa and III support fluxional tris-chelate ions. Type-IV contains distortion isomers of Cu(5,5-dmbpy)(2)NO3(+). The structural trends are analysed in terms of lanthanide contraction and non-covalent interactions in the crystals. EPR and electronic spectral characteristics are discussed for the six types of compounds.