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Title
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Synthesis and characterization of two binuclear nickel(II) complexes of thiophenol-based “end-off” compartmental ligands and their application as catalysts for selective oxidation of sulfides
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Type
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JournalPaper
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Keywords
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Binuclear Ni(II) complexes; single crystal X-ray diffraction study; sulfide; oxidation
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Abstract
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Reaction of the binucleating S-protected ligand precursors 2-(N,Ndimethylthiocarbamato)- 5-methylisophthalaldehyde di-2′-hydroxy anil (I) and 2-(N,N-dimethylthiocarbamato)-5-methylisophthalaldehyde di-2′- hydroxy 5′-methyl anil (II) with nickel(II) acetate tetrahydrate in the presence of pyrazole afforded the binuclear nickel(II) complexes [LINi2(pz)] (1) and [LIINi2(pz)] (2), respectively. The complexes have been characterized by routine physicochemical studies as well as by X-ray single crystal structure analysis. In both complexes, Ni(II) ions are doubly bridged by the thiophenolic sulfur of the pentadentate Schiff base ligand and a pyrazolate group. Efficient protocols for the oxidation of sulfides to sulfoxides with high selectivities, catalyzed by binuclear μ-thiophenolato-μ-pyrazolatonickel(II) in the presence of urea hydrogen peroxide (UHP) were explored. We obtained predominantly the monooxygenated product. The resulting products are obtained in good to excellent yields within a reasonable time.
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Researchers
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(Fifth Researcher), (Fourth Researcher), Abdeljalil Assoud (Third Researcher), Narjes Khadir (First Researcher), Mojtaba Amini (Second Researcher)
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