211322-54-2Relevant academic research and scientific papers
Syntheses, molecular structures, and reactivities of (π-allyl)rhodium(I) complexes containing bulky bis(phosphino)methanes R′2PCH2PiPr2 as ligands
Manger, Matthias,Wolf, Justin,Teichert, Markus,Stalke, Dietmar,Werner, Helmut
, p. 3210 - 3221 (1998)
The π-allyl complexes [Rh(η3-2-RC3H4)(κ 2-R′2PCH2PiPr2)] (R = H, Me; R′ = iPr, Cy, Ph) (2-7) were prepared from [RhCl(η4-C8H12)]2, 2-RC3H4MgX, and R′2PCH2PiPr2 via [Rh(η3-2-RC3H4)(η4-C 8H12)] as the intermediate. Reaction of 2-4 (R = H) with Broensted acids HX (X = Cl, CF3CO2, CF3SO3) led to cleavage of the allyl-metal bond and to the formation of the monohydridorhodium(III) compounds [RhHX2(κ2-R′2PCH 2PiPr2)] (8-12). Variable-temperature NMR measurements of 8-12 confirm that these compounds are fluctional in solution. The reaction of 2-4 with CO gave in the initial step the 1:1 adducts [Rh(η3-C3H5)(CO)(κ 2-R′2PCH2PiPr2)] (16-18), of which that with R′ = iPr was characterized by X-ray structure analysis. Compounds 16 (R′ = iPr) and 18 (R′ = Ph) reacted with excess carbon monoxide via migratory insertion of CO into the allyl-metal bond to yield the five-coordinate acylrhodium(I) complexes [Rh{C(O)CH2CH=CH2}(CO)2(κ 2-R′2PCH2PiPr2)] (19, 20). This insertion reaction is reversible. The analogous acyl compound [Rh{C(O)CH2Ph}(CO)2(κ2-iPr 2PCH2PiPr2)] (22) was obtained from [Rh(η3-CH2Ph)(κ2-iPr 2PCH2PiPr2)] and CO. Acid cleavage of the acyl-metal bond of 19 (R′ = iPr) afforded the aldehyde CH2=CHCH2CHO (26) and a mixture of 8 and [RhHCl2(CO)(κ2-iPr2PCH 2PiPr2)] (25).
