Photochemical Reactions of Transition Metal Organyl Complexes with Olefins, 21 Photolysis of Tricarbonyl(#eta#~5-cyclohexadienyl)manganese in Tetrahydrofuran, Reactions with Cumulated Dienes

摘要

[Mn(#eta#~5-C_6H_7)(CO)_3] (1) forms highly reactive [Mn(#eta#~5-C_6H_7)(CO)_2(THF)] (2) upon UV irradiation in THF at 208 K. Solvent complex 2 reacts between 208 and 293 K with 1, 1-disubstituted allenes C_3H_2RR' [R, R' = CH_3, CH_3 (A); CH_3, C_6H_5 (B); C_2H_5, C_6H_5 (C); C_6H_5 (D); OCH_3, Si(CH_3)_3 (E)] to four different types of complexes: The [5 + 2] cycloadduct [Mn(#eta#~(3 : 2)-C_9H_9RR')(CO)_3] (3E), rearranged [5 + 2] cycloadducts [Mn(#eta#~(3 : 2)-C_9H_9RR')(CO)_3] (4B, 4C, 4D), 1 is to 2 adducts [Mn(#eta#~(3 : 2)-C_(12)H_(11)R_2R'_2)(CO)_3] (5A-5E), and the 1 : 3 adduct [Mn{~#eta#~(3 : 2 : 2)-C_(15)H_(13)(CH_3)_6}(CO)_2] (6A). The constitutions of the products were established by IR and NMR spectroscopy, as well as by C,H elemental analysis and mass spectrometry. The crystal and molecular structure of 6A was determined by X-ray structure analysis. A formation mechanism for the complexes is proposed.