In:
Inorganic Chemistry Frontiers, Royal Society of Chemistry (RSC), Vol. 8, No. 24 ( 2021), p. 5214-5224
Abstract:
The formation of heterometallic clusters usually involves a much more complex self-assembly process than that of homometallic clusters. Thus the tracking of their assembly mechanism is challenging. To achieve this task, we designed one OH-containing Schiff base ligand of 1-[[(2-hydroxyethyl)imino]methyl] -2-naphthalenol (H 2 L) with coordination pockets facile for selective coordination with Co II /Ni II and 4f metal ions. Its reactions with the corresponding metal ions gave two new isostructural dodecanuclear complexes [Dy 4 Co 8 (μ 3 -OH) 8 (L) 8 (OAc) 4 (H 2 O) 4 ]·3EtOH·3CH 3 CN·H 2 O (1) and [Dy 4 Ni 8 (μ 3 -OH) 8 (L) 8 (OAc) 4 (H 2 O) 4 ]·3.5EtOH·0.5CH 3 CN·5H 2 O (2), which feature a vertex-sharing tetracubane cyclic skeleton with the four Dy III ions wrapped by the eight 3d metal ions. High-resolution electrospray mass spectrometry (HRESI-MS) tests showed that the skeletons of clusters 1 and 2 have high stability even under gradually increasing energy of the ion source. Most notably, the intermediates formed in the reaction courses for clusters 1 and 2 were tracked using time-dependent HRESI-MS, which gave different proposed assembly mechanisms for 1 (H 2 L → DyL → DyCoL → Dy 2 CoL → Dy 3 CoL → Dy 4 CoL 2 → Dy 4 Co 2 L 3 → Dy 4 Co 4 L 4 → Dy 4 Co 8 L 8 ) and 2 (H 2 L → NiL → Dy 2 NiL 2 → Dy 3 NiL 2 → Dy 4 NiL 2 → Dy 4 Ni 2 L 3 → Dy 4 Ni 4 L 3 → Dy 4 Ni 6 L 4 → Dy 4 Ni 8 L 8 ), respectively. This is the first time that different assembly mechanisms for isostructural heterometallic complexes are shown. Detailed magnetic studies revealed the absence of slow magnetic relaxation for 1 and the presence of slow magnetic relaxation for 2 with an energy barrier of 7.66 K and a pre-exponential factor of 1.45 × 10 −6 s. The different magnetic performances of the two title complexes might be caused by the different metal ions of Co( ii ) and Ni( ii ).
Type of Medium:
Online Resource
ISSN:
2052-1553
Language:
English
Publisher:
Royal Society of Chemistry (RSC)
Publication Date:
2021
