Syntheses and Characterization of μ,η¹,η¹-3,5-Di-tert-butylpyrazolato Derivatives of Aluminum

Abstract

The 3,5-di-tert-butylpyrazolato (3,5-tBu(2)pz) derivatives of aluminum [(eta(1),eta(1)-3,5-tBu(2)pz)(mu-Al)R(1)R(2)](2) (R(1) = R(2) = Me 1; R(1) = R(2) = Et, 2; R(1) = R(2) = Cl, 3; R(1) = R(2) = I, 4; [(eta(2)-3,5-tBu(2)pz)(3)Al], 5; [Al(2)(eta(1),eta(1)-3,5-tBu(2)pz)(2)(mu-E)(C triple bond CPh)(2)] (E = S (6), Se (7), Te (8)) have been prepared in good yield. Compounds 1 and 2 were obtained by the reactions of H[3,5-tBu(2)pz] with Me(3)Al and Et(3)Al, respectively. Reaction of [(eta(1),eta(1)-3,5-tBu(2)pz)(mu-Al)H(2)](2) with the pyrazole H[3,5-tBu(2)pz] gave [(eta(2)-3,5-tBu(2)pz)(3)Al] (5). The reaction of [(eta(1),eta(1)-3,5-tBu(2)pz)(mu-Al)R(2)](2) (R = H, Me) and I(2) yielded 4, while the reaction of 1 equiv of K[3,5-tBu(2)pz] and AlCl(3) afforded 3. In addition, the reaction of [Al(2)(eta(1),eta(1)-3,5-tBu(2)pz)(2)(mu-E)H(2)] and HC triple bond CPh gave 6, 7, and 8. All compounds have been characterized by elemental analysis, NMR, and mass spectroscopy. The molecular structure analyses of compounds 1, 3, 6, and 7 by X-ray crystallography showed that complexes 1 and 3 are dimeric with two eta(1),eta(1)-pyrazolato groups in twisted conformation while 6 and 7 with two eta(1),eta(1)-pyrazolato groups display a boat conformation.

A Polyhedral Aluminum Compound with an Al4C4N4 Framework

“…9 To our surprise the Al(1)−N(5) bond length (1.778(2) Å) is significantly shorter than those in comparable iminoalanes with four‐coordinate aluminum atoms (1.898(3)–1.955(3) Å)3e and even shorter than those in compounds with three‐coordinate aluminum atoms (Al−N 1.804(av)–1.824 Å),1 whereas the other Al−N bond lengths of 2 fall in the expected range (1.9265(19)–1.9698(18) Å). The Al(2)−C(5) distance (1.966(2) Å) is in accordance with those in [{( η 1 ‐ η 1 ‐ t Bu 2 pz)( μ ‐Al)Me 2 } 2 ] (Al−C 1.962(2) Å) 18b…”

Synthesis and Characterization of Derivatives of a Chelating Aluminum Dichloride Complex Containing a 3,5-Di-tert-butylpyrazolato Unit

“…The C=C bond length of the inserted trimethylsilylacetylene molecule is significantly increased [C4−C5 = 1.328(3) Å] but is slightly shorter than the C=C double bonds of the σ complex of AlCl 3 with tetramethylcyclobutadiene [1.387(3) Å]9 and 1,4‐dichloro‐2,3,5,6‐tetramethyl‐1,4‐dialumina‐2,5‐cyclohexadiene [1.367(3) Å] 10. The terminal Al(1)−C bond lengths [1.971(2) Å] are similar to those in [(η 1 ,η 1 ‐3,5‐ t Bu 2 pz)(µ‐AlMe 2 )] 2 [Al−C = 1.962(2) Å] 11…”

Aluminum Dimer Containing Bulky 1,2,3-Triazolate Ligand

“…Figure 5 illustrates the proposed reason behind this asymmetry. Other aluminum azolato complexes with either pyrazoles, 1,2,4-triazoles, or tetrazoles that exhibit a similar Al 2 N 4 ring structure do not exhibit this asymmetry [52,[56][57][58][59][60]. Instead, the Al-N-N angles are symmetrical.…”