NEW DIOXOMOLYBDENUM(VI) CATALYSTS FOR THE SELECTIVE OXIDATION OF TERMINAL N-ALKENES WITH MOLECULAR-OXYGEN

New dioxomolybdenum(VI) complexes of the type MoO(2)L(2) [L = (2'-pyri dyl)alcoholate] are able to change considerably the product distributi on of the metal catalyzed autoxidation process. With the catalyst O-{( 2'-pyridyl)pentan-3-olato}]dioxomolybdenum(VI) (2) the epoxide is form ed as the main product in the autoxidation process of 1-octene. The pr oduct selectivity is increased from 24% (epoxide, autoxidation) to 58% upon treatment of 1-octene with molecular oxygen (1 bar and 100 degre es C) in the presence of 2. An additional advantage is that the cataly st can be recovered. The synthesis and the characterization of the new dioxomolybdenum(VI) complexes and the ligands is described in additio n to their catalytic properties. The structure of the new complex ,O-{ (2'-pyridyl)pentan-3-olato}dioxomolybdenum(IV) (2) was determined by X -ray diffraction: monoclinic space group P 2(1)/c, a=1444.5(2) pm, b=1 052.3(1) pm, c=1511.5(2) pm, beta = 115.86(1)degrees, V = 2068(1)10(6 ) pm(3). The epoxidation data indicate an important influence of the l igand sphere of the catalyst on the product distribution. We have now the possibility of fine tuning the complexes in the metal catalyzed au toxidation reaction.