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Modification of aluminium alkoxides with dialkylmalonates.

Lichtenberger R, Baumann SO, Bendova M, Puchberger M, Schubert U - Monatsh. Chem. (2010)

Bottom Line: Al(malonate)3 (malonate = dimethyl, diethyl, di-iso-propyl and di-tert-butyl malonate), Al2(OiPr)4(malonate)2 (malonate = di-iso-propyl and di-tert-butyl malonate), Al2(OiPr)2(di-iso-propylmalonate)4 and Al3(OH)(OEt)3(diethylmalonate)5.An Al2(OiPr)2(dialkylmalonate)4 derivative was only obtained by disproportionation of Al2(OiPr)4(di-iso-propylmalonate)2, but not by reaction of Al(OiPr)3 with dialkylmalonates in the corresponding molar ratio.Reactions of Al(OtBu)3 only resulted in Al(malonate)3 derivatives, but no transesterification was observed, contrary to the reaction of Al(OiPr)3 with dimethyl or diethyl malonate.

View Article: PubMed Central - PubMed

Affiliation: Institute of Materials Chemistry, Vienna University of Technology, Vienna, Austria.

ABSTRACT

Abstract: Depending on the reaction conditions, different aluminium dialkylmalonate derivatives were obtained by reaction of aluminium alkoxides Al(OR)3 (R = Et, iPr, tBu) with dialkylmalonates, viz. Al(malonate)3 (malonate = dimethyl, diethyl, di-iso-propyl and di-tert-butyl malonate), Al2(OiPr)4(malonate)2 (malonate = di-iso-propyl and di-tert-butyl malonate), Al2(OiPr)2(di-iso-propylmalonate)4 and Al3(OH)(OEt)3(diethylmalonate)5. All compounds were characterized by NMR spectroscopy, and single crystal structure analyses are reported for each type of compound. An Al2(OiPr)2(dialkylmalonate)4 derivative was only obtained by disproportionation of Al2(OiPr)4(di-iso-propylmalonate)2, but not by reaction of Al(OiPr)3 with dialkylmalonates in the corresponding molar ratio. Reactions of Al(OtBu)3 only resulted in Al(malonate)3 derivatives, but no transesterification was observed, contrary to the reaction of Al(OiPr)3 with dimethyl or diethyl malonate.

No MeSH data available.


Related in: MedlinePlus

Molecular structure of 2d (hydrogen atoms omitted for clarity)
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Fig6: Molecular structure of 2d (hydrogen atoms omitted for clarity)

Mentions: The single crystal structure analysis of 2d was in agreement with that derived from NMR spectra in solution (Fig. 6). The bite angles for the two malonate ligands at the octahedral Al centre are 90.29(7)° and 90.39(7)°. One of the malonate ligands again shows a slightly envelope-like conformation, whereas the other one is nearly planar. Interestingly, no trans influence on the Al–O bond distances (188.26(15)–188.98(17) pm) was observed for the malonate ligands. The angle between the two bridging OiPr groups O(3)–Al(2)–O(4) at the octahedral Al centre is only 76.61(7)° and leads to a distortion of the coordination octahedron. As expected, the bond distances Al(2)–O(3) and Al(2)–O(4) between the octahedral Al centre and the bridging OiPr are significantly longer than those from the tetrahedral Al centre to the bridging units, viz. 190.34(17) and 190.21(16) pm vs. 179.78(16) (Al(1)–O(3)) and 179.13(17) (Al(1)–O(4)) pm. In addition, the O(3)–Al(1)–O(4) angle at the tetrahedral Al centre (82.17(7)°) is larger than that at the octahedral centre, as expected due to the different coordination geometry. Both bond distances to the terminal OiPr groups Al(1)–O(1) and Al(1)–O(2) of 169.82(19) and 169.78(18) pm, respectively, are significantly shorter than those to the bridging OiPr groups. Comparison with Al2(OiPr)4(tert-butyl acetoacetate)2 shows similar bond distances and angles, with the bond distances Al–Omalonate lying between those for Al–Oester (190.4(4)–192.6(4) pm) and Al–Oketo (185.0(4)–187.2(4) pm). The ketoesterate ligands in this structure also show both envelope and twisted conformation [12].Fig. 6


Modification of aluminium alkoxides with dialkylmalonates.

Lichtenberger R, Baumann SO, Bendova M, Puchberger M, Schubert U - Monatsh. Chem. (2010)

Molecular structure of 2d (hydrogen atoms omitted for clarity)
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4494765&req=5

Fig6: Molecular structure of 2d (hydrogen atoms omitted for clarity)
Mentions: The single crystal structure analysis of 2d was in agreement with that derived from NMR spectra in solution (Fig. 6). The bite angles for the two malonate ligands at the octahedral Al centre are 90.29(7)° and 90.39(7)°. One of the malonate ligands again shows a slightly envelope-like conformation, whereas the other one is nearly planar. Interestingly, no trans influence on the Al–O bond distances (188.26(15)–188.98(17) pm) was observed for the malonate ligands. The angle between the two bridging OiPr groups O(3)–Al(2)–O(4) at the octahedral Al centre is only 76.61(7)° and leads to a distortion of the coordination octahedron. As expected, the bond distances Al(2)–O(3) and Al(2)–O(4) between the octahedral Al centre and the bridging OiPr are significantly longer than those from the tetrahedral Al centre to the bridging units, viz. 190.34(17) and 190.21(16) pm vs. 179.78(16) (Al(1)–O(3)) and 179.13(17) (Al(1)–O(4)) pm. In addition, the O(3)–Al(1)–O(4) angle at the tetrahedral Al centre (82.17(7)°) is larger than that at the octahedral centre, as expected due to the different coordination geometry. Both bond distances to the terminal OiPr groups Al(1)–O(1) and Al(1)–O(2) of 169.82(19) and 169.78(18) pm, respectively, are significantly shorter than those to the bridging OiPr groups. Comparison with Al2(OiPr)4(tert-butyl acetoacetate)2 shows similar bond distances and angles, with the bond distances Al–Omalonate lying between those for Al–Oester (190.4(4)–192.6(4) pm) and Al–Oketo (185.0(4)–187.2(4) pm). The ketoesterate ligands in this structure also show both envelope and twisted conformation [12].Fig. 6

Bottom Line: Al(malonate)3 (malonate = dimethyl, diethyl, di-iso-propyl and di-tert-butyl malonate), Al2(OiPr)4(malonate)2 (malonate = di-iso-propyl and di-tert-butyl malonate), Al2(OiPr)2(di-iso-propylmalonate)4 and Al3(OH)(OEt)3(diethylmalonate)5.An Al2(OiPr)2(dialkylmalonate)4 derivative was only obtained by disproportionation of Al2(OiPr)4(di-iso-propylmalonate)2, but not by reaction of Al(OiPr)3 with dialkylmalonates in the corresponding molar ratio.Reactions of Al(OtBu)3 only resulted in Al(malonate)3 derivatives, but no transesterification was observed, contrary to the reaction of Al(OiPr)3 with dimethyl or diethyl malonate.

View Article: PubMed Central - PubMed

Affiliation: Institute of Materials Chemistry, Vienna University of Technology, Vienna, Austria.

ABSTRACT

Abstract: Depending on the reaction conditions, different aluminium dialkylmalonate derivatives were obtained by reaction of aluminium alkoxides Al(OR)3 (R = Et, iPr, tBu) with dialkylmalonates, viz. Al(malonate)3 (malonate = dimethyl, diethyl, di-iso-propyl and di-tert-butyl malonate), Al2(OiPr)4(malonate)2 (malonate = di-iso-propyl and di-tert-butyl malonate), Al2(OiPr)2(di-iso-propylmalonate)4 and Al3(OH)(OEt)3(diethylmalonate)5. All compounds were characterized by NMR spectroscopy, and single crystal structure analyses are reported for each type of compound. An Al2(OiPr)2(dialkylmalonate)4 derivative was only obtained by disproportionation of Al2(OiPr)4(di-iso-propylmalonate)2, but not by reaction of Al(OiPr)3 with dialkylmalonates in the corresponding molar ratio. Reactions of Al(OtBu)3 only resulted in Al(malonate)3 derivatives, but no transesterification was observed, contrary to the reaction of Al(OiPr)3 with dimethyl or diethyl malonate.

No MeSH data available.


Related in: MedlinePlus