311817-77-3Relevant academic research and scientific papers
Half-sandwich type rhodium(I) complexes with arenes and functionalized arenes C6H5X(CH2)nPR2 (R = iPr, tBu) as nonchelating and chelating ligands
Werner, Helmut
, p. 4756 - 4766 (2008/10/08)
A series of arenerhodium(I) complexes [(η6-arene)Rh(C8H14)(PiPr3)]PF6 (2-6) were prepared, from the highly reactive starting material cis-[Rh(C8H14)(PiPr3)(acetone)2]PF 6 (1) and the arene in CH2Cl2 in excellent yields. The related ethene compound [(η6-C6H6)Rh(C2H4)(PiPr3)]P F6 (7) was obtained by stirring a solution of the corresponding cyclooctene derivative 2 under an ethene atmosphere. Reaction of cis-[Rh(C8H14)2(acetone)2]PF6 (10) with the new alkyldiisopropylphosphines iPr2P(CH2)nC6H5(8, n = 2;9, n = 3), which were prepared from HPiPr2 and C6H5(CH2)nBr in the presence of ammonia, in the molar ratio of 1:1 gave the half-sandwich type complexes [{η6-C6H5(CH2)nPiPr2 -κ-P}Rh (C8H14)]PF6 (11,12). They afforded upon treatment with a second equivalent of 8 or 9 the bis(phosphine) compounds [{η6-C6H5(CH2)nPiPr2- κ-P}{C6H5(CH2)nPiPr2 -κ- P}Rh]PF6 (13, 14). The NMR spectra of 13 and 14 are not temperature-dependent, and therefore a fluxional behavior in solution can be excluded. The cyclooctene ligand of 11 could easily be displaced by ethene, maleicacid anhydride, ethyl propiolate, and triisopropylstibine to generate the substitution products 15-18 in 80-90% yield. Similarly, the ethene complex 19 was obtained from 12 and C2H4. The even more bulky alkyldi-tert-butylphosphines tBu2P(CH2)nXC6H5 (20, n = 1, X = CH2; 21, n = 2, X = O) and their respective olefin and alkyne rhodium(I) complexes 22a, 23, and 24 were prepared by using the same methodology as applied for the iPr2P counterparts. The corresponding triflate [{η6-C6H5(CH2)2PtBu2- κ-P}Rh(C8H14)]CF3SO3 (22b) was obtained from the dimer 25 and the phosphine 20 as starting materials. The molecular structures of 11, 12, and 19 were determined by X-ray crystallography.
