330463-17-7Relevant academic research and scientific papers
Synthesis and structure of piano stool complexes derived from the tetrakis(pentafluorophenyl)cyclopentadienyl ligand
Thornberry, Matthew P.,Slebodnick, Carla,Deck, Paul A.,Fronczek, Frank R.
, p. 920 - 926 (2001)
The reaction of NaCp (Cp = C5H5) with excess C6F6 and excess NaH in refluxing diglyme afforded a 57% yield of 1,2,3,4-tetrakis(pentafluorophenyl)cyclopentadiene (1). Treatment of 1 with NaH in THF afforded sodium tetrakis(pentafluorophenyl)cyclopentadienide (2) in 89% yield. Reactions of 2 with M(CO)5Br (M = Mn, Re) yielded [(C6F5)4C5H]M(CO)3 complexes (3, M = Mn, 33%, and 4, M = Re, 28%). Reactions of 2 with various iron(II) salts and with CoBr2 however failed to afford the corresponding octaarylated metallocenes. Infrared spectroscopic analysis of 3 and 4 revealed an increase of 16(1) cm-1 relative to CpM(CO)3 in the A-symmetric C-O stretching frequency, suggesting that the C6F5 groups have a highly electron-withdrawing effect on the coordinated M(CO)3 moieties. Crystal structures of 1, 1·1/2C6D6, 2, and 3 display a propeller-like arrangement of the C6F5 groups. Complexes 2 and 3 show elongation of the C5(centroid)-M bond distances relative to CpMn(CO)3 and CpRe(CO)3, which is attributed to steric effects.
