Tuning Dimensions of Complexes through Selective In Situ Reaction, Mechanistic Insights into Ni(II)-Catalyzed Br-OH Exchange, Magnetic Properties, and Density Functional Theory Studies.

Two coordination polymers (CPs), namely, [Mn 3 (L) 2 (4,4'-bipy) 2 (H 2 O) 2 ] n ( 1 ) and [Ni(L 1 )(1,4-bib)(H 2 O)] n ( 2 ) (H 3 L = 5-(3-bromo-4-carboxyphenoxy)isophthalic acid, H 2 L 1 = 5-(3-hydroxyphenoxy)isophthalic acid, 4,4'-bpy = 4,4'-bipyridine, and 1,4-bib = 1,4-bis(1 H -imidazol-1-yl)benzene), were synthesized under hydrothermal conditions. Most notably, with the help of the bromine atom-inducing effect, ligand transformation was observed in the structure of complex 2 , which was scrutinized thoroughly by single crystal X-ray crystallography and X-ray photoelectron spectroscopy (XPS). Strikingly, Ni(II) ions were utilized as both coordinated atoms and as a catalyst for in situ Br-OH exchange of H 3 L in the process, as a result of which the product would have preferred to form a one-dimensional chain. The same reaction cannot happen in 1 , leading to form a two-dimensional structure. Moreover, Ni(II)-catalyzed and magnetic exchange mechanisms were well interpreted using density functional theory (DFT) calculations. Finally, complexes 1-2 show three-dimensional (3D) supramolecular structures because of intermolecular weak interactions (C-Br···π, C-H···π, C-H···O, and π···π stacking) and exhibit utterly different antiferrimagnetic coupling interactions.