Morphology dependant oxidation of aromatic alcohols by new symmetrical copper(II) metallatriangles formed by self-assembly of a shared bis-benzimidazolyl diamide ligand

作者：Mahiya Kuldeep; Mathur Pavan^*

来源：Inorganica Chimica Acta, 2013, 399: 36-44.

DOI：10.1016/j.ica.2012.12.037

• Benzimidazolyl diamide
• Crystal structure
• Asymmetric unit
• Morphology
• Catalytic oxidation
• 4-Methyl benzyl alcohol

A new bis-benzimidazole-based diamide ligand N-2,N-2%26apos;-bis((1H-benzo[d]imidazol-2-yl)methyl)-[1,1%26apos;-biphenyl]-2,2%26apos;-dicarboxamide, L and its three Cu(II) metallatriangles of general formula [Cu-3(L)(3)X-3]-center dot 3X center dot nH(2)O (where X = Cl, Br, NO3) have been synthesized and one of them is structurally characterized. X-ray diffraction work reveals that the metallatriangle [Cu-3(L)(3)Cl-3]center dot 3Cl center dot 15H(2)O crystallizes in trigonal R (3) over bar space group with two independent molecules in the asymmetric unit. The asymmetric unit contains only one-third of the molecules and the rest are generated by the crystallographic (3) over bar axis. Each copper(II) ion adopts a highly distorted square pyramidal geometry. The copper(II) metallatriangles are used as catalyst to carry out the oxidation of substituted benzyl alcohols heterogeneously, in the presence of tert-butyl hydroperoxide. Interestingly, the ratio of product profile and the percentage conversion of the products changes with the surface morphology of the metallatriangle employed as a catalyst. A kite type morphology is found to be highly selective to the formation of acid product over the aldehyde, while a hexagonal type morphology results in a mixed acid + aldehyde product. The initial rate of formation of the aldehyde is found to be almost independent of the amount of catalyst employed.

• 出版日期2013-4-1