IR spectroscopic investigations into reactions between unsaturated titanium complexes and CO or N-2 in liquid xenon or heptane

The reactions of Cp-2*TiR compounds with CO in liquid xenon (LXe) or heptane were studied by IR spectroscopy in special high-pressure cells. All complexes incorporate a single CO molecule to fill up their coordination sphere, forming Cp-2*TiR(CO) intermediates. These species undergo secondary reactions at elevated temperatures, such as disproportionation to Ti(II) and Ti(IV) complexes. The formation of the 18 VE species Cp-2*Ti(CO)(2) seems to be the driving force of the observed reactions. A similar behavior was found in the reaction of Cp-2*TiH with dinitrogen, where the adduct Cp-2*TiH(N-2) and its N-14'15(2) isotopomer was identified together with Cp-2*Ti(N-2)(2). In addition to these orientating experiments, the stable 15 VE Cp*FvTi (Fv = eta(6)-C5Me4CH2) and 16 VE species Cp*AdTi (Ad = eta(7)-C5Me3(CH2)(2)) show the addition of carbon monoxide to form new, reactive titanium carbonyls, which undergo ligand exchange reactions at higher temperatures and form Cp-2*Ti(CO)(2) as one of the final products. (C) 1997 Elsevier Science B.V.