877785-79-0Relevant academic research and scientific papers
1,2-bis{(pentafluorophenyl)phenylphosphino}ethane: A probe for configurational stability in three-legged piano stool complexes
Nieuwenhuyzen, Mark,Saunders, Graham C.,Sarah Smyth
, p. 996 - 1003 (2006)
The pentafluorophenyl-substituted diphosphine (C6F 5)PhPCH2CH2PPh(C6F5) has been prepared, as a 1:1.7 mixture of rac (1a) and meso (1b) isomers, in four steps from dppe. The reaction between [Cp*RhCl(μ-Cl)]2 and 1 in the presence of tetrafluoroborate yielded a mixture of racemic diastereoisomers of [Cp*RhCl(κP,κP-1a)][BF4] (4a·BF4) and trans and cis isomers of [Cp*RhCl(κP, κP-1b)][BF4] (4b·BF4 and 4c·BF 4, respectively). On addition of Proton Sponge, 4a and 4c, in which at least one pentafluorophenyl group is close to the pentamethylcyclopentadienyl ligand, underwent rapid dehydrofluorinative carbon-carbon coupling giving trans- and cis-[{η5,κP,κP-C5Me 4CH2C6F4-2-PPhCH2CH 2PPh(C6F5)}RhCl]+ (5 · and 6), respectively. The latter underwent further dehydrofluorinative carbon-carbon coupling to give two isomers of [{η5,κP,κP-C 5Me3[CH2C6F4-2-PPhCH 2]2}RhCl]+ (7). Isomerization of 4b to 4c was observed in chloroform and dimethlysulfoxide. Neither isomerization of 4a to 4b or 4c nor isomerization of 5 to 6 was observed at ambient or elevated temperature in dimethyl sulfoxide. The results provide the first evidence that complexes of η5,κP,κL-cyclopentadienyl-phosphine- donor ligands are configurationally stable at high temperature.
