Three new one-, two-, and three-dimensional complexes based on semi-rigid tricarboxylate ligand: Syntheses, structures and properties

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, [Mn₃(L)₂(4,4'-bipy)₂(H₂O)₂]_n (1) and [Ni(L₁)(1,4-bib)(H₂O)]_n (2) (H₃L = 5-(3-bromo-4-carboxyphenoxy)isophthalic acid, H₂L₁ = 5-(3-hydroxyphenoxy)isophthalic acid, 4,4'-bpy = 4,4'-bipyridine, and 1,4-bib = 1,4-bis(1H-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 H₃L 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.

A new 3D 8-connected Cd(ii) MOF as a potent photocatalyst for oxytetracycline antibiotic degradation

1 exhibits the best photocatalytic decomposition efficiency towards antibiotic OXY. The plausible photocatalytic mechanism has been explained with the help of the density of states calculations and Hirshfeld surface analysis.