148339-09-7Relevant articles and documents
Interaction of organic carbonyls with sterically crowded aryloxide compounds of aluminum
Power, Michael B.,Bott, Simon G.,Clark, David L.,Atwood, Jerry L.,Barron, Andrew R.
, p. 3086 - 3097 (1990)
The interaction of AlR(BHT)2 and AlR2(BHT)(OEt2) (R = Me, Et) with organic carbonyls O=C(X)R (X = H, R′, OR, NR2) leads to the formation of the Lewis acid-base complexes AlR(BHT)2[O=C(X)R] and AlR2(BHT)[O=C(X)R], respectively. The aluminum-methyl 13C NMR chemical shifts for the methyl aryloxide compounds AlMe(BHT)2[O=C(X)R] and AlMe2(BHT)[O=C(X)R] are found to be dependent primarily on the steric bulk of the substituents, X and R, on the carbonyl ligand. In contrast, the decrease in the carbonyl stretching frequency in the IR spectrum, and the downfield shift in the 13C NMR spectrum for the carbonyl α-carbon of the carbonyl adducts, when compared to those of the "free" carbonyls, is dependent on the electron-donating ability of X. The molecular structures of AlMe(BHT)2[O=C(H)But] (1), AlMe2(BHT)(O=CPh2) (8), and AlMe(BHT)2[O=C(OMe)Ph] (17) have been determined by X-ray crystallography. The mode of coordination of the organic carbonyls to aluminum is discussed. Crystal data for 1: monoclinic, P21/n, a = 10.0765 (5) A?, b = 26.201 (2) A?, c = 14.0106 (4) A?, β = 103.638 (3)○, Z = 4, R = 0.0576, Rw = 0.0623. Crystal data for 8: orthorhombic, Pn21a, a = 19.133 (3) A?, b = 14.638 (2) A?, c = 10.022 (1) A?, Z = 4, R = 0.0552, Rw = 0.0550. Crystal data for 17: triclinic, P1?, a = 9.394 (2) A?, b = 9.741 (3) A?, c = 23.091 (7) A?, α = 91.43 (2)?, β = 91.93 (2)?, γ = 116.41 (2)?, Z = 2, R = 0.0599, Rw = 0.0689.
