Diverse Structures Based on a Heptanuclear Cobalt Cluster with 0D to 3D Metal–Organic Frameworks: Magnetism and Application in Batteries

Polymetallic complexes with interesting multifunctions have attracted extensive investigation. Synthesized through the use of different cobalt salt anions and solvents, five complexes, namely [CoII4CoIII3(H2L)3Cl5(MeOH)] (1), [CoII4CoIII3(H2L)3(CH3COO)4(HCOO)⋅H2O]n (2), [CoII4CoIII3(H2L)3(HCOO)4(NO3)⋅2H2O]n (3), [CoII4CoIII3(H2L)3(bda)(CH3COO)4⋅2H2O]n (4), and [CoII4CoIII3(H2L)3(ipa)(HCOO)3(dmf)⋅H2O]n (5) (H6L=bis‐tris propane; BDA=biphenyl‐4,4′‐dicarboxylic acid; IPA=isophthalic acid; DMF=N,N‐dimethylformamide), based on the heptanuclear {CoII4CoIII3} cluster with structures from 0D to 3D metal–organic frameworks (MOFs) have been solvothermally synthesized. Compound 1 is the first 0D heptanuclear cluster based on H6L. Compound 2 crystallizes in the chiral space group P212121 and consists of a 1D chiral helical chain. Complex 3 exhibits a 3D network structure. Compound 4 possesses a 1D zigzag‐like chain structure. Finally, compound 5 was obtained as a 3D microporous structure. Compounds 1, 3, and 4 display dominant ferrimagnetic interactions whereas compounds 2 and 5 exhibit antiferromagnetic interactions. Moreover, the Co3O4 prepared by calcining compound 2 presents a reversible capacity of 1122.9 mA h g−1 at 0.2 A g−1 after 100 cycles and an excellent rate capability, which suggests that coordination compounds with a 1D chain structure are outstanding precursors for preparing anode materials for lithium ion batteries.