Complexes of thiophene-2,3-dicarboxaldehyde bis(oxime) (2,3BTCOH2) with nickel(II) and copper(II): Synthesis, characterization, crystal structure of 2,3BTCOH2. Rearrangement reaction with nickel(II) bromide

Reacting with nickel(II) chloride, copper(II) chloride and bromide, thiophene-2,3-dicarboxaldehyde bis(oxime) (2,3BTCOH2) leads to metal complexes formulated as [NiCl2(2,3BTCOH2)], [CuCl2(2,3BTCOH2)] and [CuBr(2,3BTCOH)]2 respectively. In the case of nickel(II) bromide, we have observed the rearrangement of 2,3BTCOH2 into 2-acetamido-3-thiophene carboxaldoxime (ACTOH) instead of the expected complex. The crystal structures of 2,3BTCOH2 and ACTOH have been determined by X-ray diffraction methods and all other structures are proposed using usual spectroscopic techniques.

Graphical abstractReacting with nickel(II) chloride, copper(II) chloride and bromide, thiophene-2,3-dicarboxaldehyde bis(oxime) (2,3BTCOH2) leads to [NiCl2(2,3BTCOH2)], [CuCl2(2,3BTCOH2)] and [CuBr(2,3BTCOH)]2 complexes. In the case of nickel(II) bromide, we have observed the unexpected rearrangement of 2,3BTCOH2 into 2-acetamido-3-thiophene carboxaldoxime (ACTOH) instead of the expected complex.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Rearrangement of only one functional group for a bis(oxime). ► Catalytic rearrangement with Ni2+. ► Crystal structure of thiophene-2,3-dicarboxaldehyde bis(oxime). ► Crystal structure of 2-acetamido-3-thiophene carboxaldoxime.