174646-28-7Relevant academic research and scientific papers
Reactions of the schiff base rhodium hydride complex RhH(Bu4salophen) with olefins. Observations and mechanistic studies
Anderson, D. Joe,Eisenberg, Richard
, p. 1697 - 1706 (1996)
The tetradentate dianionic Schiff base ligand Bu4salophenH2 reacts with [RhCl(C2H4)2]2 and NR4OH (R = n-Bu, Et) to produce the complexes RhR(Bu4salophen) (1, R = n-Bu; 2, R = Et), which undergo photolysis (λ > 475 nm) under a hydrogen atmosphere to generate RhH(Bu4salophen) (3) and the corresponding alkanes. In benzene at room temperature, olefins insert into the metal-hydride bond of 3 to produce Rh(CH2CH2R)(Bu4salophen) (2, R = Et; 4, R = Ph; 5, R = CN). In a competition experiment, insertion of styrene is only slightly favored over that of ethylene. For olefinic substrates capable of radical rearrangement (CH2=CHR where R = CH2OCH2CH=CH2 and c-C3H5), insertion products are formed that do not correspond to radical rearrangements. Specifically, Rh(CH2CH2OCH2CH=CH2)(Bu 4salophen) (6) is observed as the only product of the reaction of 3 with bis(allyl) ether while Rh(CH2CH2-C-C3H5)(Bu 4Salophen) (7) is seen as the major product in the reaction with vinylcyclopropane. For the vinylcyclopropane reaction, additional products are also identified by 2D NMR methods as Rh(CH2CH2CH=CHCH3)(Bu4salophen) (8) and (Bu4salophen)Rh-(λ-CH2CH2CH=CHCH 2)Rh(Bu4Salophen) (9). Both the poor selectivity for styrene versus ethylene insertion and the absence of radical rearranged product with bis(allyl) ether and vinylcyclopropane indicate that, in the reaction of 3 with olefins, an intermediate containing a pure carbon-based radical is not involved.
