The Coordination Structure of the Extracted Nickel( II ) Complex with a Synergistic Mixture Containing Lix63 and Versatic10

In the present work, the nickel( II ) synergist complex with isobutyric acid ( HL I ) and 5‐hydroxy‐4‐octanone oxime ( HB I ), which were the corresponding short‐chain analogs of the active synergistic mixture of Versatic10 ( HL ) and Lix63 (5,8‐diethyl‐7‐hydroxy‐6‐dodecanoneoxime, HB ), was prepared and studied by single‐crystal X‐ray diffraction ( XRD ). The crystal structure of the nickel( II ) synergist complex showed that the composition of the complex was Ni( L I ) 2 ( HB I ) 2 with a cis ‐form octahedron geometry structure. Both intra‐ and intermolecular hydrogen bonding were observed in the crystal lattice. Compared with the free ligands, similar band shifts of Fourier transform infrared ( FT‐IR ) spectra assigned to the stretching vibration of carbon–oxygen single bond (CO), the stretching vibration of carbon–nitrogen double bond (CN), and the disappearance of the scissoring vibration of α‐hydroxy ( OH ) were correspondingly found in both the nickel( II ) synergist complex and the extracted nickel( II ) complex in the nonpolar organic phase. Combined with the results from ESI‐MS , XRD , and slope analysis, it was concluded that the major species of the extracted nickel( II ) complex in the nonpolar organic phase might possess a similar coordination structure [Ni( HB ) 2 (L) 2 ] as the nickel( II ) synergist complex, along with the neutral complex [Ni( HB )(B) 2 ].