Reactivity of cyclopentadienyl transition metal(II) complexes with borate ligands: structural characterization of the toluene-activated molybdenum complex [Cp*Mo(CO)2(η3-CH2C6H5)]

Reactions of cyclopentadienyl transition-metal halide complexes [Cp*Mo(CO)(3)Cl], 1, and [CpFe(CO)(2)I], 2, (Cp = C5H5; Cp*=eta(5)-C5Me5) with borate ligands are reported. Treatment of 1 with [NaBt(2)] (Bt(2) = dihydrobis(2-mercapto-benzothiazolyl) borate) in toluene yielded [Cp*Mo(CO)(2)(C7H4S2N)], 3, and [Cp*Mo (CO)(2)(eta(3)-CH2C6H5)], 4, with a selective binding of toluene through C-H activation followed by ortho-metallation. Note that compound 4 is a structurally characterized toluene-activated molecule in which the metal is in. 3-coordination mode. Under similar reaction conditions, [NaBt(2)] (Bt(2) = dihydrobis(2-mercaptopyridyl) borate) produced only the mercaptopyridyl molybdenum complex [Cp*Mo(CO)(2)(C5H4SN)], 5, in good yield. On the other hand, when compound 2 was treated individually with [NaBt] (Bt = trihydro(2-mercapto-benzothiazolyl) borate) and [NaPy2] in THF, formation of the. 1-coordinated complexes [CpFe(CO)(2)(C7H4S2N)], 6, and [CpFe(CO)(2)(C5H4SN)], 7, was observed. The solid-state molecular structures of compounds 3, 4, 6, and 7 have been established by single-crystal X-ray crystallographic analyses.