Darstellung, charakterisierung und reaktivität der metallcyclischen alkenylketon-komplexe Cp*(CO) 2[formula omitted])Me] (Cp* = η 5-C 5Me 5; R 1, R 2 = H. Me, Ph, CH 2OH, (CH 2) 2Me, (CH 2) 5Me)

Abstract

The photoinduced reaction of Cp*Cr(CO) 3Me (Cp* = η 5-C 5Me 5) and alkynes R 1CCR 2 (R 1, R 2 = H, Me, Ph, CH 2OH, (CH 2) 2Me, (CH 2) 5Me) yields the metallacyclic alkenylketone complexes Cp*(CO) 2 Cr[R 1CCR 2C(O )Me] and the isomers Cp*(CO) 2 Cr[R 2CCR 1C(O )Me] (II). Complexes II show high reactivity: they react with PMe 3 yielding the CO substitution products Cp*(CO)(PMe 3) Cr[R 1CCR 2C(O )Me] (R 1 = H; R 2 = H, Ph) as well as the ylidic metallacyclopropane adduct Cp*(CO) 2 Cr[(PMe 3)HCC HCOMe]. The reaction of Cp*(CO) 2 Cr[HCCHC(O )Me] with NO gives Cp*Cr(NO) 2NO 2; with ClNO the products formed are Cp*Cr(NO) 2Cl and [Cp*Cr(NO)Cl] 2. Complexes II and CF 3COOH or HCl gas release the free alkenylketone R 1HCCR 2COMe and the paramagnetic products Cp*Cr(CF 3COO) 2 and [Cp*CrCl 2] 2. Photolysis of II in CHCl 3 yields [Cp*CrCl 2] 2, H 2R 1CCR 2HCOMe and Cl 2CCHCl.