Perfluoroalkylation of Coordinated Ethene in Rh(I) and Ir(I) Complexes. Catalytic Addition of Iodoperfluoroalkanes to Ethene
作者:María Blaya、Delia Bautista、Juan Gil-Rubio、José Vicente
DOI:10.1021/acs.organomet.6b00929
日期:2017.4.10
The complexes [M(eta(5)-CP*)(eta(2)-C2H4)(2)] (M = Rh, Ir) react with iodoperfluoroalkanes to give [M(eta(5)-Cp*)(CH2CH2RF)(mu-I)](2) (main product) and (CH2CH2RF)(mu-I)(2)M(eta(5)-Cp*)I] (RF = t-C4F9, M = Ir; R-F = c-C6F11, M = Ir, Rh). Similarly, the complexes [M(eta(5)-Cp*)(eta(2)-C2H4)(PPh3)] react with iodoperfluoroalkanes to give [M(eta(5)-Cp*)(CH2CH2RF)I(PPh3)] (M = Ir, R-F = t-C4F9, i-C3F7; M = Rh, R-F = t-C4F9). Evidence for the generation of the heptafluoroisopropyl carbanion in the reaction of [Ir(eta(5)-Cp*)(eta(2)-C2H4)(PPh3)] with I-i-C3F7 was obtained, which suggests that the reaction is initiated by the transfer of two electrons from the Ir(I) complex to the iodoperfluoroalkane. The iodo-bridged complexes react with PPh3 to give [M(eta(5)-Cp*)(CH2CH2RF)I(PPh3)] (M = Ir, R-F = t-C4F9; c-C6F11; M = Rh, R-F = c-C6F11). The complexes [Ir(eta(5)-Cp*)(CH2CH2RF)I(PPh3)] (RF = c-C6F11, i-C3F7) react with AgOTf to give [Ir(eta(5)-Cp*)H(eta(2)-CH2=CHRF)(PPh3)]OTf. The analogous reaction of [Ir(eta(5)-Cp*)(CH2CH2-t-C4F9)I(PPh3)] gives CH3CH2-t-C4F9 and [Ir(eta(5)-Cp*)(eta(2)-o-C6H4PPh2)]OTf, which reacts with PPh3 to give [Ir(eta(5)-Cp*)(eta(2)-o-C6H4PPh2)(PPh3)]OTf. This cyclometalated complex and its analogue [Ir(eta(5)-Cp*)(eta(2)-o-C6H4PPh2)(P(p-Tol)(3))]OTf are also prepared by the reaction of [Ir(eta(5)-Cp*)(Me)Cl(PPh3)] with AgOTf and PPh3 or P(p-Tol)(3). The derivatives [Ir(eta(5)-Cp*)(CH2CH2RF)(PPh3)L]OTf (L = CO, R-F = c-C6F11; i-C3F7; L = PPh3, R-F = i-C3F7) are isolated in the reactions of the Ir hydrido alkene complexes with CO or PPh3.The reactions of [Rh(eta(5)-Cp*)(CH2CH2RF)I(PR3)] (R = Me, R-F = i-C3F7, n-C4F9, t-C4F9; R = Ph, RF = i-C3F7, t-C4F9, c-C6F11) with AgOTf afford unstable triflato complexes that decompose to give CH2=CHRF, but in the presence of PR3 the complexes [Rh(eta(5)-Cp*)(CH2CH2RF)(PR3)(2)]OTf (R = Ph, R-F = i-C3F7; t-C4F9, c-C6F11; R = Me, R-F = i-C3F7, t-C4F9) were formed. When R = Ph, these complexes are unstable and decompose quantitatively to give [Rh(eta(5)-Cp*)H(PPh3)(2)]OTf and CH2=CHRF. Complexes of the type [M(eta(5)-Cp*)(eta(2)-C2H4)(2)] (M = Rh, Ir) and [Rh(eta(5)-Cp*)(CH2CH2RF)I(L)] are initiators for the radical addition of IRF to ethene.