A Structurally Diverse Series of Aluminum Chloride Alkoxides [ClxAl(m-OR)y]n (R = nBu, cHex, Ph, 2.4-tBu2C6H3)
| Authors | |
|---|---|
| Year of publication | 2009 |
| Type | Article in Periodical |
| Magazine / Source | INORGANIC CHEMISTRY |
| MU Faculty or unit | |
| Citation | |
| Field | Inorganic chemistry |
| Keywords | aluminum chloride alkoxides |
| Description | A diverse series of aluminum chloride alkoxides, [ClxAl(m-OR)y]n (R=nBu, cHex, Ph, 2,4-tBu2C6H3), was synthesized using the reactions of dichlorethylalane (EtAlCl2) with cyclohexanol (cHexOH), n-butanol (nBuOH), and phenols (PhOH and 2,4-tBu2C6H3OH). Eight molecular products were isolated and structurally characterized. The dimeric [Cl2Al(m- OcHex)2AlCl2] (1) was the smallest oligomer isolated among the cyclohexanolate derivatives. The adduct of 1 with cyclohexanol is a dinuclear molecule [Cl2(HOcHex)Al(m-OcHex)2AlCl2] (2) which represents a possible intermediate in the conversion reaction leading to the formation of a trinuclear bicyclic [ClAl{(m-OcHex)2AlCl2}2] (3). Two polymorphic forms of 3 were isolated. Further coordination of cyclohexanol to the Lewis acidic five-coordinate aluminum atom in 3 provided [Cl(HOcHex)Al{(m-OcHex)2AlCl2}2] (4) with octahedrally coordinated central aluminum. Compound 4 could be regarded as a precursor to the well-known Mitsubishi (tridiamond) tetranuclear species. The reactions of EtAlCl2 with less sterically demanding nBuOH yielded a cyclic trimer, [Cl2Al(m-OnBu)]3 (5), and a unique trinuclear ionic species, [Cl2Al{(m-OH)(m- OnBu)AlCl(HOnBu)3}2]Cl (6) with a linear Al(m-O)2Al(m-O)2Al core. In the reactions with phenols, the aromatic groups preferentially stabilized dimeric structures of [Cl2Al(m-OR)2AlCl2] (R = Ph, 7; 2,4-t Bu2C6H3, 8). Since these compounds could be considered as intermediates in the nonhydrolytic condensation reactions of metal halides with metal alkoxides, a mixture of EtAlCl2 with cHexOH was used as a precursor for the nonaqueous synthesis of alumina by alkylhalide elimination. |
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