Author(s)

Mohamed A. El-Sayed¹, Hoda A. Elwakeil¹, Ahmed H. Abdel Salam^1,2*, Hemmat A. Elbadawy^1,3

¹Chemistry Department, Faculty of Science, Alexandria University, Alexandria, Egypt.
²Chemistry Department, Faculty of Science, University of Jeddah, Jeddah, Saudi Arabia.
³Chemistry Department, Faculty of Science, University of Tabuk, Tabuk, Saudi Arabia.

In this work, novel oxidative coupling complexes, [(Pip)_4nCu₄X₄(CO₃)₂] (n = 1 or 2, X = Cl or Br, Pip = piperidine), are synthesized from the reaction of well characterized Lewis base [(Pip)_4nCu₄X₄O₂] with carbon dioxide as a Lewis acid in CH₂Cl₂. These carbonato-derivatives are isolated as stable solids. They are easily soluble in aprotic solvents as CH₂Cl₂or phNO₂. Cryoscopic measurements support tetranuclear structure for all of them. Electronic spectra in the near infrared with high molecular absorptivity may be explained for tetranuclear cuban structure to fulfil 3 halo-ligands for each copper centre in [(Pip)_4nCu₄X₄(CO₃)₂]. The EPR spectra for [(Pip)_4nCu₄X₄(CO₃)₂] complexes are axial type of spectra (d_x2-y2 G.S) suggesting elongated tetragonal distortion for all of them. Cyclic voltammograms for [(Pip)_4nCu₄X₄(CO₃)₂] are irreversible in character. These tetranuclear carbonato complexes show catalytical activity. They initiate the oxidation of 2,6-dimethylphenol (DMP) to 3,3’,5,5’-tetramethyl-4,4’-diphenoquinone (DPQ).

Complexes, Tetranuclear Cuban, Carbonato Bridge, Copper

El-Sayed, M. , Elwakeil, H. , Salam, A. and Elbadawy, H. (2016) Synthesis and Characterization of Novel μ-Carbonato Tetranuclear Copper Complexes [(Pip)_4nCu₄X₄(CO₃)₂] in Aprotic Media. Open Journal of Inorganic Chemistry, 6, 66-75. doi: 10.4236/ojic.2016.61004.