Syntheses, Crystal Structures, and Magnetic Properties of Novel Copper(II) Complexes with the Flexible Bidentate Ligand 1-Bromo-3,5-bis(imidazol-1-ylmethyl)benzene

Seven new metal−organic frameworks (MOFs) [Cu(bib)2(H2O)2](Cl3CCOO)2·2MeOH·2H2O (1), [Cu(bib)2]Cl2·H2O
(2), [Cu(bib)2(SO4)(H2O)]·4H2O (3), [Cu(bib)(SO4)(H2O)2] (4), [Cu(bib)(N3)(OAc)]·DMF (5) (OAc = acetate), [Cu(bib)(ox)]·MeOH·2H2O (6) (ox = oxalate), and [Cu(bib)(mal)]·MeOH (7) (mal = malonate) were obtained by reactions of flexible bidentate ligand
1-bromo-3,5-bis(imidazol-1-ylmethyl)benzene (bib) with corresponding copper(II) salts. The structures of these MOFs were established
by single-crystal X-ray diffraction analysis. Complexes 1 and 2 have similar one-dimensional (1D) hinged chain structure. Complex
3 has a 2D network structure with (4,4) topology. Complex 4 has M2L2 metallocyclic ring structure and the rings are further linked
by the sulfate anions to form a 1D tube-like chain. Complex 5 is also a dinuclear M2L2 metallocyclic ring, which is further connected
by Br···Br interactions to form 1D chain. While in the cases of complexes 6 and 7, both have 2D network structure in which the
oxalate and malonate anions act as bridging ligands. The results showed that the counteranions play important roles in the construction
of MOFs. In addition, the magnetic properties of complexes 6 and 7 were investigated. The results show that weak ferromagnetic
interactions occurred between the copper(II) ions linked by the oxalate anions in complex 6, and there is no obvious magnetic
interaction between the copper(II) ions bridged by the malonate anions in complex 7.