Inorganic Chemistry, Vol.40, No.20, 5077-5082, 2001
Coordinatively unsaturated W(IV)-bis(pyridine) complexes, a reactive source of W(IV)
Addition of 2 equiv of a a-donor ligand (L = pyridine, 4-picoline, or quinoline) to complexes of the type [W(NPh)-(eta (4)-arene)(o-(Me3SiN)(2)C6H4)] (arene = CH3CH2C6H5 (3), CH3CH2CH2C6H5 (4)) gave the W(IV)L-2 compounds, [W(NPh)(o-(Me3SiN)(2)C6H4)(C5H5N)(2)](5), [W(NPh)(o-(Me3SiN)(2)C6H4)(p-C6H7N)(2)](6), and [W(NPh)(o-(Me3SiN)(2)C6H4)(C9H7N)(2)] (7). Synthesis of compounds 5 and 6 by Na degrees reduction of [W(NPh)(o-(Me3SiN)(2)C6H4)Cl-2] in the presence of 3 equiv of L (L = 5, pyridine or 6, 4-picoline) is also presented. Compounds 5, 6, and 7 display hindered rotation of the donor ligands about the W-N bonds, resulting from a steric interaction with the Me3Si groups of the diamide ligand. The coordinative unsaturation of 5 and 6 has also been explored. Compounds 5 and 6 readily react with either CO and PMe3 to generated the six coordinate complexes [W(NPh)(o-(Me3SiN)(2)C6H4)(C5H5N)(2)(CO)] (8a), [W(NPh)(o-(Me3SiN)(2)C6H4)(C6H7N)(2)(CO)] (8b), [W(NPh)(o-(Me3SiN)(2)C6H4)(C5H5N)(PMe3)(2)] (10a), and [W(NPh)(o-(Me3SiN)(2)C6H4)(C6H7N)(PMe3)(2)] (10b), respectively.