Synthesis, Crystal Structures, and Solvent Effect of Two Solvent-Induced Supramolecular Co^II Complexes

Abstract

Two solvent-induced complexes, [CoL₂(CH₃OH)₂] (1) and [CoL₂(CH₃CH₂OH)₂] (2), have been synthesized by the reaction of an oxime-type ligand (HL, 4-[(Ethoxyimino)(phenyl)methyl]-5-methyl-2-phenyl-1H-pyrazol-3(2H)-one) with cobalt(II) acetate tetrahydrate in different solvents. X-ray crystallographic analyses have indicated that complexes 1 and 2 have a similar structure, consisting of one Co^II atom, two L⁻ units, and two coordinated methanol or ethanol molecules. Interestingly, two Co^II atoms in the structures of complexes 1 and 2 are all six-coordinated, approaching a staved octahedral geometry, but complexes 1 and 2 are grown up in methanol/chloroform and ethanol, respectively. Right because of this, solvent effect cause to the difference of the crystal structures: complex 1 forms an infinite supramolecular chain by intermolecular hydrogen bonds, while complex 2 exhibits three-dimensional supramolecular networks through intermolecular hydrogen bonds and C-H···π interactions.

Keywords:

• complex
• crystal structure
• oxime-type ligand
• solvent effect
• synthesis

Acknowledgments

This work was supported by the Foundation of the Education Department of Gansu Province (0904–11) and the ‘Jing Lan’ Talent Engineering Funds of Lanzhou Jiaotong University, which are gratefully acknowledged.