Synthesis and reactivity of the imidotungsten methyl cation [W(N2Npy)(NPh)Me]+: CO2 adds to the W=NPh bond and does not insert into the W-Me bond
Résumé
The imidotungsten dimethyl compound [W(N2Npy)(NPh)Me-2] 2 reacts with BAr3F to form the cationic complex [W(N2Npy)(NPh)Me](+) 3(+) [anion = [Me-BAr3F]-; Ar-F C6F5; N2Npy MeC(2-C5H4N)(CH2NSiMe3)(2)] which undergoes methyl group exchange with added 2, [Cp2ZrMe2] or ZnMe2; treatment of cation 3(+) with CO2 or isocyanates leads to cycloaddition reactions at the W=NPh bond and not insertion into the W-Me bond, despite the latter product being the most thermodynamically favourable according to DFT calculations.