TY - JOUR
T1 - Reactivity studies and structural outcomes of a bulky dialkylaluminium amide in the presence of the N-Heterocyclic Carbene, ItBu
AU - Pollard, Victoria A.
AU - Fuentes, Maria-ngeles
AU - Robertson, Stuart D.
AU - Weetman, Catherine
AU - Kennedy, Alan R.
AU - Brownlie, Josh
AU - Angus, Fraser J.
AU - Smylie, Cooper
AU - Mulvey, Robert E.
PY - 2021/9/22
Y1 - 2021/9/22
N2 - Aluminium reagent iBu2Al(TMP) (TMP is 2,2,6,6-tetramethylpiperidide) has previously shown interesting synergistic metallation chemistry when paired with alkali metal amides. Here its structural chemistry and reactivity is explored in the presence of the N-heterocyclic carbene, ItBu, 1,3-di-tert-butylimidazol-2-ylidene. Abnormal aItBu structures are obtained with iBu2Al(TMP) on its own and in the co-presence of LiTMP, NaTMP or KTMP. Reaction with phenol is stoichiometric dependent leading to the diphenolate [ItBu(H)]+ [(PhO)2Al(iBu)2 and triphenolate [ItBu(H)]+ [(PhO)3Al(iBu)- ionic complexes. Dinuclear aItBu(Ph)C=N[Al(iBu)2N=C(TMP)Ph]Al(iBu)2 was the surprising product from reaction with benzonitrile, displaying an imidoC- and (iBu)2Al- disubstituted imidazolium ring as well as a second imido unit made by addition of "non-nucleophilic" TMP across the benzonitrile triple bond. Potential insight into the mechanism of this intriguing complicated reaction was gained through the crystallographic characterisation of the ketamide [iBu2AlN=C(Ph)TMP]2, a possible intermediate. Reaction with Ph2CHCN, diphenylacetonitrile, proved more straightforward affording the ionic complex [ItBu(H)]+ [Ph2C=C=N]-.
AB - Aluminium reagent iBu2Al(TMP) (TMP is 2,2,6,6-tetramethylpiperidide) has previously shown interesting synergistic metallation chemistry when paired with alkali metal amides. Here its structural chemistry and reactivity is explored in the presence of the N-heterocyclic carbene, ItBu, 1,3-di-tert-butylimidazol-2-ylidene. Abnormal aItBu structures are obtained with iBu2Al(TMP) on its own and in the co-presence of LiTMP, NaTMP or KTMP. Reaction with phenol is stoichiometric dependent leading to the diphenolate [ItBu(H)]+ [(PhO)2Al(iBu)2 and triphenolate [ItBu(H)]+ [(PhO)3Al(iBu)- ionic complexes. Dinuclear aItBu(Ph)C=N[Al(iBu)2N=C(TMP)Ph]Al(iBu)2 was the surprising product from reaction with benzonitrile, displaying an imidoC- and (iBu)2Al- disubstituted imidazolium ring as well as a second imido unit made by addition of "non-nucleophilic" TMP across the benzonitrile triple bond. Potential insight into the mechanism of this intriguing complicated reaction was gained through the crystallographic characterisation of the ketamide [iBu2AlN=C(Ph)TMP]2, a possible intermediate. Reaction with Ph2CHCN, diphenylacetonitrile, proved more straightforward affording the ionic complex [ItBu(H)]+ [Ph2C=C=N]-.
KW - abnormal carbene
KW - alkali-metal
KW - N-heterocyclic carbene
KW - NMR studies
KW - organoaluminium compound
U2 - 10.1016/j.poly.2021.115469
DO - 10.1016/j.poly.2021.115469
M3 - Article
SN - 0277-5387
VL - 209
JO - Polyhedron
JF - Polyhedron
M1 - 115469
ER -