Cyclopentanolates of Aluminum Hydride/Aluminum Chloride forming Aluminum-Oxygen-Hetero-Cages and Mixed Coordination Oligomers

Lithium aluminum hydride combined with different amounts of aluminum chloride react with cyclopentanol under the formation of compounds with aluminum-oxygen scaffolds and hydrogen or chlorine as terminating substituents at aluminum and cyclopentyl at the oxygen atoms. H6Al4(OC5H9)6 and Cl6Al4(OC5H9)6, both displaying a central aluminum atom almost octahedrally coordinated by oxygen atoms of the cyclopentanolates with three AlH2 or AlCl2 entities bridging three oxygen edges were isolated and fully characterized. The compound dihydrido aluminum cyclopentanolate was isolated together with chloro-hydrido aluminum cyclo-pentanolate as a 6:2 aggregate, [H2Al(OC5H9)]6[H(Cl)Al(OC5H9)]2, displaying alcoholate and hydride bridges in the crystal. Structural isomers of this compound were found in the solid. Mono-hydrides could be isolated in the form of H5Al5(O)(OC5H9)8*OC4H10 and in the form of a hydride/chloride H4.5Cl0.5Al5(O)(OC5H9)8*OC4H10, which is a 1:1 mixture of H5Al5(O)(OC5H9)8 with H4ClAl5(O)(OC5H9)8 in the crystal. In both compounds an oxygen atom is in the center of an Al5 square pyramid. While in the first case the aluminum atom situated at the top of the pyramid has a hydride ligand, in the second case the ligand is a chloride.