Reactivity Studies of (tBu3SiNH)(tBu3SiN=)2WH Including Anionic Derivatives Featuring the Tris-tri-tert-butylsilylimide Tungsten Core

[GRAPHIC] Treatment of ((Bu3SiNH)-Bu-t)((Bu3SiN)-Bu-t=)(2)WH (1-H) with CX4 (X = Cl, Br, I) afforded ((Bu3SiNH)-Bu-t)((Bu3SiN)-Bu-t=)(2)WX (1-X, X = Cl, Br, I), but metatheses of 1-X with R- equivalents gave mixed results. With MeLi, ((Bu3SiNH)-Bu-t)((Bu3SiN)-Bu-t=)(2)WR (1-R, R = CH3) was produced, but ArLi gave 1-Ar along with [((Bu3SiN)-Bu-t=)(3)WAr]Li (2-Li-Ar) and [((Bu3SiN)-Bu-t=)(3)WH]VI (2-M-H, M = Li). Alkylation attempts with BnK and 1-X cause deprotonation (X = Cl) to provide [((Bu3SiN)-Bu-t=)(3)WX]M (2-M-X, M = K, X = Cl) and apparent electron transfer when X = I to give 1-Bn, 2-K-H, and bibenzyl. Two equivalents of (BuLi)-Bu-t and 1-Cl afforded 2-Li-H via deprotonation of 1-H and byproducts likely derived from electron transfer. Exposure of 1-H to C2H4, C3H6, methylenecyclopentane, butadiene, propyne, (HCCBu)-Bu-t, p-tolunitrile, and tert-butylisocyanide gave insertion products 1-R (R = Et, Pr-n, CH(2)(c)Pe, E-CH2CH=CHMe, CH=CHIvIe, CH=(CHBu)-Bu-t), 1-N= CHtol, and 1-CH=(NBu)-Bu-t, respectively. Thermolysis of 1-CH=(NBu)-Bu-t gave the cyanide complex 1-CN. 1-H and 1-Me resisted dihydrogen and methane elimination in nondonor solvents at 200 C, but in pyridine, 1-H lost H-2 in a second-order process to give ((t)B(3)u3SiN=)(3)Wpy (Delta G degrees(414k) = 4.5 kcal/mol). Thermolysis of 2-py under D-2 in C6D6 provided a-deuterated py. 2-M-H (M = Li, Na, K) and 2-K-R (R = Me, Et, Pr-n) were generated by deprotonation of 1-H and 1-R, respectively, and various 1-M-X were synthesized similarly and via exposure of 1-Li-H to alkyl halides. Treatment of 2-Li-H with CH3I provided 2-Li-I, but byproducts 1-CH3 and 1-I suggested the potential intermediacy of a methane complex. X-ray crystal structures of 2-py, 2-H-K(OEt2)(3), 2-H-K(crypt-2.2.2), the dimer [2-H](2)(mu-K)(2) (i.e., 2-K-H), and the trimer [2-I](3)(mu-K)(3) (i.e., 2-K-I) revealed similar tris-imido cores. Discussion of the general reactivity of 1-H, structural features, and plausible mechanisms of 2-py formation are included.