Distortion Isomerism of Cu(II) Chloride Adducts with Bis(2-benzimidazolyl)ethane. Synthesis, Characterization, X-ray Structures and Spectroscopy of Four Different Isomers

Metals in Catalysis, Biomimetics & Inorganic Material

A structural study of copper(II) carboxylates: Crystal structure and physical characterisation of [Cu₂(2-bromopropanoato)₄(caffeine)₂]

Based on the bond-valence sum model the continual transition between the bidentate and monodentate bonding mode of carboxylato group and minimum of Cu–O bond lengths were estimated. The dependence of Cu⋯Cu separation on Cu–N bond length in binuclear Cu(II) carboxylates with caffeine were derived and fitted to the observed data. The crystal structure of [Cu₂(2-bromopropanoato)₄(caffeine)₂] has been determined by X-ray crystallography. The structure consists of centrosymmetric binuclear units where the two Cu atoms are coordinated by four disordered bridging 2-bromopropionates and two caffeine ligands at the apices of a bicapped square prism. Both 2-bromopropionates show disorder of their –Br and –CH₃ substituents. Stacking π·π interactions between the adjacent caffeine molecules link the complex units in 1-D networks. The binuclear structure of the studied compound is consistent with magnetic data and EPR spectrum