Formal nitrogen hydride insertion into the metal-carbene bond of fischer-type carbene complexes

Article abstract of DOI:10.1021/om00151a028

A series of imidate complexes [(CO)₅M{NH=C(OR¹)R²)] (M = W, R¹ = Me or Et, R² = Ph; M = W, R¹ = Me, R² = Me; M = Cr, R¹ = Me or Et, R² = Ph) can be prepared by reaction of alkoxyorganocarbene complexes with S,S-diphenylsulfilimine, NH=SPh₂. The thiocarbene complex [(CO)₅W{C(SPh)R²)] (R² = Me) similarly gives the corresponding thioimidate complex, but when R² = Ph, [(CO)₅W(NCPh)] (9) is the only product. The heterometallocyclic complex [(CO)₄W{C(OEt)C(OEt)=CS(CH₂)₃S}] also undergoes NH insertion and concomitant chelate ring enlargement. The imidate complex [(CO)₅W{NH=C(OMe)Ph}] (1) is deprotonated by Bu^-, H^-, MeO^-, and RS^- to afford the nitrile (9), but with dimethylamine the amidine complex [(CO)₅W{NH=C(NMe₂)Ph}] (13) is formed by aminolysis. The Z isomer of 1 and the E isomer of 13 are completely characterized by X-ray structure determinations. Crystal data for 1: WC₁₃H₉NO₆, M_r 459.07, monoclinic, space group P2₁/c, a = 10.694 (4) ?, b = 6.650 (1) ?, c = 20.338 (4) ?, β = 92.18 (3)°, V = 1445 ?³, Z = 4, D_calcd = 2.11 g cm^-3. Crystal data for 13: WC₁₄H₁₂N₂O₅, M_r 472.118 monoclinic, space group P2₁/c, a = 11.723 (2) ?, b = 9.550 (1) ?, c = 15.032 (6) ?, β = 105.43 (3)°, V = 1622 ?³, Z = 4, D_calcd = 1.93 g cm^-3. The W-N(sp²) bond lengths are 2.249 (5) and 2.243 (5) ?. Reaction of NH=SPh₂ with [M(CO)₆] (M = Cr or W) produces yellow solutions from which [(CO)₅M(SPh₂)] can be isolated. In the presence of PPh₃ only the monosubstituted phosphine complexes form in less than 50% yields.