Preparation and characterization of half-sandwich cobalt(III) complexes of Cp ligands with a rigid thioanisole side-chain

Abstract

New sulfur functionalized cyclopentadiene ligands, 1-[2-(thioanisole)]-2,5-dimethylcyclopentadiene (3), 1-[2(thi oanisole)]-2,3,5-trimethylcyclopentadiene (4), and 1-[2-(thioanisole)]-2,3,4,5-tetramethylcyclopentadiene (5), were prepared. In these ligands, the S-donor atom is connected to a cyclopentadiene ring by a rigid phenylene spacer. CpCo(III)-diiodo, half-sandwich complexes (6-8) were obtained from reaction the ligands (35) with Co-2(CO)8, followed by treatment Of I-2. Substitution reaction of CpCo(Ill)-diiodo complexes with MeLi yielded the corresponding CpCo(III)-dimethyl complexes (9-11). Further transformation to the corresponding cationic cobalt complexes (12-14) were achieved by reaction of the CpCo(III)-dimethyl complexes with HB(ArF)(4).2Et(2)O and trapping with CD3CN. The new sulfur functionalized cyclopentadiene ligands having a rigid phenylene spacer and the corresponding cobalt complexes were characterized by H-1, C-13 and F-19 NMR spectroscopy. The diiodo Complex 6 was also characterized by a single crystal X-ray diffraction method.