REACTIVITY OF THE LEWIS-ACIDS CP-ASTERISK-M(NO)(CH2CME3)CL [M = MO, W] AND RELATED COMPLEXES

{Treatments of Cp*M(NO)Cl2 [Cp* = eta5-C5Me5; M = Mo, W] with 0.5 equiv of (Me3CCH2)2Mg.X(dioxane) in THF at low temperatures affords the monoalkylated complexes, Cp*M(NO)(CH2CMe3)Cl (1, 1’). Exposure to a second 0.5 equiv of (Me3CCH2)2Mg.X(dioxane) at higher temperatures produces the dialkyl complexes, Cp*M(NO)(CH2CMe3)2 (2,2’). Utilizing the two series of Cp*M(NO)Cl2, Cp*M(NO)(CH2CMe3)Cl and Cp*M(NO)(CH2CMe3)2 complexes, the relative electron deficiencies in these 16-electron complexes can be assessed spectroscopically and electrochemically. Without exception, the Mo complexes are the stronger Lewis acids. Also, the mononeopentyl derivatives for both metals are more reactive toward a variety of substrates than are their bis(neopentyl) analogues. Complexes 1 and 1’ serve as precursors to mixed alkyl and alkyl aryl complexes (3, 3’, 4, 4’) and yield metal-centered adducts with PMe3 and pyridine (5, 5’, 6, 6’). CO and CNCMe3 readily insert into the M-C bonds of 1 and 1’. The insertion products, Cp*M(NO)(C{E}CH2CMe3)Cl (7, 7’