Two Heterometallic Nanoclusters [Dy III 4 Ni II 8 ] and [Dy III 10 Mn III 4 Mn II 2 ]: Structure, Assembly Mechanism, and Magnetic Properties.

A full understanding of the assembly mechanisms of coordination complexes is of great importance for a directional synthesis under control. We thus explored here the formation mechanisms of the two new heterometallic nanoclusters [Dy III 4 Ni II 8 (μ 3 -OH) 8 (L) 8 (OAc) 4 (H 2 O) 4 ]·3.25EtOH·4CH 3 CN ( 1 ) and [Dy III 10 Mn III 4 Mn II 2 O 4 (OH) 12 (OAc) 16 (L) 4 (HL) 2 (EtOH) 2 ]·2EtOH·2CH 3 CN·2H 2 O ( 2 ) with different cubane-based squarelike ring structures, which were obtained from the reactions of 4-bromo-2-[(2-hydroxypropylimino)methyl]phenol (H 2 L) with Dy(NO) 3 ·6H 2 O and the transition metal salt Ni(OAc) 2 ·4H 2 O or Mn(OAc) 2 ·4H 2 O. The high-resolution electrospray ionization mass spectrometry (HRESI-MS) tests showed that the skeletons of clusters 1 and 2 have a high stability under the measurement conditions for HRESI-MS. The intermediates formed in the reaction courses of clusters 1 and 2 were tracked using time-dependent HRESI-MS, which helped to determine the proposed hierarchical assembly mechanisms for 1 (H 2 L → NiL → Ni 2 L 2 → Ni 3 L 4 → Ni 4 L 4 → DyNi 4 L 5 → Dy 2 Ni 6 L 6 → Dy 3 Ni 6 L 6 → Dy 3 Ni 7 L 7 → Dy 4 Ni 8 L 8 ) and 2 (H 2 L → MnL → DyMnL → DyMn 2 L → Dy 2 Mn 2 L x → Dy 8 Mn 2 L 2 → Dy 10 Mn 2 L 2 → Dy 10 Mn 6 L x and H 2 L → DyL → Dy 4 L 2 → Dy 6 L 2 → Dy 8 Mn 2 L 2 → Dy 10 Mn 2 L 2 → Dy 10 Mn 6 L x ). This is one of the rare examples of investigating the assembly mechanisms of 3d-4f heterometallic clusters. Magnetic studies indicated that the title complexes both show slow magnetic relaxation behaviors and cluster 1 is a field-induced single-molecule magnet.