Syntheses, Structures and Magnetism of trinuclear bimetallic MnIILnIIIMnII Complexes (Ln = La, Nd, Sm, Gd, Dy and Er) with 2,6‐Dipicolinoylbis(N,N‐diethylthiourea)

Self‐assembled reactions of 2,6‐dipicolinoylbis( N , N ‐diethylthiourea) (H 2 L) with Mn(CH 3 COO) 2 ⋅ 4H 2 O and LnCl 3 , where Ln = La, Nd, Sm, Gd, Dy, Er in MeOH lead to formation of stable trinuclear complexes of the composition [LnMn 2 (L) 2 (μ 1,3 ‐CH 3 COO) 2 X] (Mn II Ln III Mn II ), where X − can be κ 2 ‐CH 3 COO − or κ 1 ‐CH 3 COO − . Single crystal X‐ray studies reveal their symmetric structures comprising one central Ln(III) ion, two terminal Mn(II) ions sandwiched by two doubly deprotonated ligands {L 2− }. The magnetic properties of Mn II La III Mn II and Mn II Gd III Mn II complexes are successfully simulated using symmetrical magnetic interaction models, giving the best fitted parameters: J Mn‐Mn =−0.120(1) cm −1 , g Mn =1.99(1), TIP=4.45(7) ⋅ 10 −4 cm 3 mol −1 K for Mn II La III Mn II and J Gd‐Mn =0.042(1) cm −1 , J Mn‐Mn =−0.076(1) cm −1 , g Mn =1.96(1), g Gd =2.01(1) and TIP=3.59(14) ⋅ 10 −4 cm 3 mol −1 K for Mn II Gd III Mn II complex. The magnetic interactions between the Mn(II) and Ln(III) ions in the other Mn II Ln III Mn II complexes are studied by comparing their χ M values to the sum of χ M values of the Mn II La III Mn II and the analogous Zn II Ln III Zn II complexes. The Mn II Er III Mn II complex reveals a strong ferromagnetic interaction, while the Sm, Nd, Gd and Dy complexes show weak ferromagnetic interactions.