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)

Abstract

AbstractA 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)] ⋅ 2CH3CN (Ln=Ce, Pr); Type‐IIa, [Cu(5,5‐dmbpy)3][Ln(NO3)5(OH2)] ⋅ 2CH3CN (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)2NO3]+. 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.