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- Title
Multinuclear Magnetic Resonance Study on Aluminium Sec-butoxide Chelated with Ethyl Acetoacetate in Various Amounts.
- Authors
Kurajica, Stanislav; Kraljević, Tatjana Gazivoda; Mali, Gregor; Simčić, Ivan; Mandić, Vilko; Minga, Iva
- Abstract
Reactive aluminum alkoxide (ASB, aluminium sec-butoxide) was chelated using ß-diketone (EAA, ethyl acetoacetate) in order to gain control over rapid hydrolysis in the course of the sol-gel process. Derived chelates were analysed using several NMR spectroscopic techniques: one-dimensional 1H, 13C, 27Al NMR and two-dimensional COSY, HSQC and DOSY. The NMR analysis enabled identification of the formed chelate species, as well as determination of their quantitative relationships. Several complexation products were observed: tris-chelated monomer, Al(EAA)3, bis-chelated dimmer, Al2(OnBu)4(EAA) 2, tris-chelated dimmer, Al2(OnBu)3(EAA)3, tetra-chelated dimmer, Al2(OnBu)2(EAA)4, and monochelated trimer, Al3(OnBu)8(EAA). Of the formed oligomer compounds, this is the first evidence of Al2(OR)3L3 in any alkoxide and ß- ketoester or ß-diketone combination. Aluminium sec-butoxide and ethyl acetoacetate complexes Al2(OnBu)4(EAA) 2 and Al2(OnBu)2(EAA)4 were also observed for the first time. With the increase of the EAA/ASB ratio the coordination of aluminium shifts towards six, whereas above the EAA/ASB ratio of 2.5 solely six-coordinated aluminium exists.
- Subjects
ETHYL acetoacetate; MAGNETIC resonance; ALUMINUM; SOL-gel processes; CHELATES
- Publication
Croatica Chemica Acta, 2019, Vol 92, Issue 1, p17
- ISSN
0011-1643
- Publication type
Article
- DOI
10.5562/cca3426