Giant Enlarged Circular Metallo-Rings

Facilitated by the tert -butyl substituent in a C 2 -symmetric bis(hydrazone), along with the incorporation of 3 d ions, oxalate, carbonate, and sodium ions, a homononanuclear dysprosium ring [Dy 9 (L 1 ) 3 (μ 3 -O) 4 (μ 3 -AcO) 3 (μ 2 -AcO) 6 (μ 2 -COO) 3 (DMF) 3 ]·3DMF·1MeOH·6H 2 O ( Dy 9 ) and a heterooctaoctacontanuclear dysprosium–zinc–sodium ring [Dy 48 Zn 24 Na 16 (L 2 ) 24 (μ 6 -C 2 O 4 ) 8 (μ 4 -C 2 O 4 ) 18 (μ 4 -CO 3 ) 8 (μ 4 -AcO) 34 (μ 4 -COO) 16 (DMF) 10 (H 2 O) 28 ]·2Cl·46DMF·38MeCN·82H 2 O ( Dy 48 Zn 24 Na 16 ) were synthesized. Compounds Dy 9 and Dy 48 Zn 24 Na 16 exhibit distinct single- and triple-stranded cyclic topologies, in which the bis(hydrazone) ligands L 1 and L 2 adopt different conformations and exhibit distinct metal coordination modes. While 12 acetate molecules serve as terminal coligands occupying the remaining coordination sites in assembly Dy 9, hexacosuple-C 2 O 4 2–, octuple-CO 3 2– and triacontatetraple-AcO – bridges act as mixed oxoanion templates to form Dy 48 Zn 24 Na 16 by linking hexanuclear Dy 6 Zn 3 Na 2 (L 2 ) 3 building blocks. Sixteen sodium ions act as a tertiary template, filling the internal void of the latter structure. Furthermore, it was observed that the structural modifications largely influence the zero-field magnetic relaxation behavior. This work presents a new approach for constructing C 2 O 4 2– -, CO 3 2– - and AcO – - bridged heterometallic metallosupramolecular rings through the deliberate addition of oxalate, carbonate and acetate for magnetic dynamic studies.