Novel Metal−Organic Frameworks with Specific Topology Formed through Noncovalent Br···Br Interactions in the Solid State

Two coordination polymers [Ag(bib)]NO3·H2O (1) and [Ag(bib)]ClO4 (2) with one-dimensional (1D)
chain structure were synthesized by reactions of ditopic ligand containing imidazole donors, namely, 1-bromo-3,5-bis(imidazol-1-ylmethyl)benzene (bib), with corresponding silver salts. While the bib ligand reacted with ditopic
diacetato-zinc(II) acceptors, M2L2-type metallocyclic ring-like complex [Zn2(bib)2(OAc)4]·2H2O (OAc = acetate anion)
(3) was obtained, which was further connected by Br···Br interactions to lead to the formation of 1D pseudo-polyrotaxane. When ligand bib reacted with Zn(NO3)2·6H2O and Mn(NO3)2, two complexes [Zn(bib)2(H2O)2](NO3)2·2H2O (4) and [Mn(bib)2(H2O)2](NO3)2·2H2O (5) with 2D network structure were obtained in which the metal atoms
had octahedral coordination geometry. The structures of these coordination complexes were determined by X-ray
crystallography, and the results revealed that the coordination geometry of metal atoms have a great impact on the
structure of the supramolecular architectures. Furthermore, the nitrate anions located in the voids between the 2D
cationic layers in 4 can be exchanged by nitrite anions, which means that complex 4 with 2D network structure has
anion exchange properties.