Matrix isolation investigation of the reaction of (CH3)(3)Al with O-2

The matrix isolation technique has been employed to isolate and characteriz e the initial intermediate in the reaction of (CH,),AI with O-2. Using a fl ow gas reactor system immediately prior to matrix; deposition, evidence of reaction was noted only when a constricted nozzle was employed. Under these conditions, four product bands that can be assigned to a single product sp ecies were formed. Oxygen isotopic labeling and comparison with literature spectra identified the product species as monomeric (CH,)(2)A1OCH(3). Exper imental and theoretical evidence are also presented to support the conclusi on that (CH3)(3)A1OO is not the initial product of this reaction. Heating t he deposition line to as high as 350 degrees C destroyed the initial bands and led to the formation of one or more secondary species. These could not be conclusively identified; the well-known dimer [(CH3)(2)AIOCH(3)](2) is t he most likely candidate. The fact that the reaction only occurred with a c onstricted nozzle suggests that O-2 is reacting with the trimethylaluminum dimer, across the four-membered ring to form two molecules of (CH3)(2)A1OCH (3). (C) 1999 Elsevier Science S.A. All rights reserved.