Synthesis, characterization, and single crystal structure determination of an oxo-derivative of methylaluminum containing asymmetric carbon

摘要

Dimeric dimethylaluminum Compound, {Me2Al[mu-OCH(CH3)CH2OCH3]}(2), was synthesized by the reaction of trimethylaluminum and 1-methoxy-2-propanol, an alkoxyalcohol containing asymmetric carbon, and characterized by H-1, C-13, and Al-27 NMR spectroscopy. The 1-methoxy-2-propoxodimethylaluminum, as shown by the single crystal structure determination, exists as a dimer in the solid-state in which the ether alkoxide ligand chelates to the aluminum atom. The solution structure was probed by H-1, C-13, and Al-27 NMR spectroscopy and the results showed that the five-coordinate isomer is in equilibrium with the four-coordinate isomer. However, variable-temperature Al-27 NMR spectroscopy showed only the presence of five-coordinate isomer at - 15 degrees C and below.