206664-65-5Relevant academic research and scientific papers
Reactivity studies of (tBu3SiNH)(tBu 3SiN=)2WH including anionic derivatives featuring the tris-tri- tert -butylsilylimide tungsten core
Schafer, Daniel F.,Wolczanski, Peter T.,Lobkovsky, Emil B.
, p. 6539 - 6561 (2011)
Treatment of (tBu3SiNH)(tBu 3SiN=)2WH (1-H) with CX4 (X = Cl, Br, I) afforded (tBu3SiNH)(tBu3SiN=) 2WX (1-X, X = Cl, Br, I), but metatheses of 1-X with R- equivalents gave mixed results. With MeLi, (tBu3SiNH) (tBu3SiN=)2WR (1-R, R = CH3) was produced, but ArLi gave 1-Ar along with [(tBu3SiN=) 3WAr]Li (2-Li-Ar) and [(tBu3SiN=) 3WH]M (2-M-H, M = Li). Alkylation attempts with BnK and 1-X cause deprotonation (X = Cl) to provide [(tBu3SiN=) 3WX]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 tBuLi 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, C 3H6, methylenecyclopentane, butadiene, propyne, HCC tBu, p-tolunitrile, and tert-butylisocyanide gave insertion products 1-R (R = Et, nPr, CH2cPe, E-CH 2CH=CHMe, CH=CHMe, CH=CHtBu), 1-N=CHtol, and 1-CH=N tBu, respectively. Thermolysis of 1-CH=NtBu 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 H2 in a second-order process to give (tBu3SiN=)3Wpy (ΔG°414K = 4.5 kcal/mol). Thermolysis of 2-py under D 2 in C6D6 provided α-deuterated py. 2-M-H (M = Li, Na, K) and 2-K-R (R = Me, Et, nPr) 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(μ-K)2 (i.e., 2-K-H), and the trimer [2-I]3(μ-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.
