89199-72-4Relevant academic research and scientific papers
Study of the amination reaction of the coordinated cyclopentadienyl ring in (η5-Cp)FeL1L2X derivatives. Crystal and molecular structure of (η5-C5H4NEt 2)Fe(CO)[PhP(OEt)2]Br
Brun, Pierre,Vierling, Pierre,Riess, Jean G.,Le Borgne, Guy
, p. 1032 - 1040 (2008/10/08)
The influence of the nature of X, L1, L2, and the NR2 anions on the reaction between LiNR2 and (η5Cp)FeL1L2X derivatives 6 (L1 = CO, L2 = PR3; L1 = L2 = PR3; X = Cl, Br) has been investigated in order to explore the extent and potential in synthesis of the amination reaction of the coordinated cyclopentadienyl ring in 6. A rather complex situation was found with up to five different reaction products isolated or identified: the main derivatives that formed were the aminated adducts (η5-C5H4NR2)FeL 1L2X (9) and (η5-C5H4NR2)FeL 1L2H (10) and the diiron species [(η5-C5H5)Fe(L)(μ-CO)]2 (13). The results show indeed that there is a significant influence of the nature of the halogen X, the ligands L1 and L2, and the amide anions NR2- on the amination process. (i) It leads to C5H4NR2 adducts only when R ≠ H. (ii) Much higher yields in aminated derivatives 9 and/or 10 are obtained starting from the (η5-Cp)FeL(CO)X or (η5-Cp)FeL1L2X derivatives than from the (η5-Cp)Fe(CO)2X adducts while, on electronic grounds, the latter were expected to be the most suitable candidates: this illustrates the prominent role played by the steric effects of the ligands. (iii) The π-acceptor character of the ligand L plays, however, an important role and favors the amination process: in the case of (η5-Cp)FeL(CO)X derivatives, when L = P(OPh)3 or PhP(OR)2, C5H4NR2 compounds (9 and 10) are obtained in 57-88% yields while for the bulkier PPh3 ligand the yield is only of 31%. This effect is even more drastic in the case of (η5-Cp)FeL2Br derivatives: while, for L = PhP(OEt)2, the amination reaction occurs in good yield (74%), no aminated adduct was detected for L2 = dppe which is a better donating ligand than PhP(OEt)2. (iv) The brominated derivatives 6 are much better starting materials than their chlorinated analogues. Compound 9d, (η5-C5H2NEt 2)Fe(CO)[PhP-(OEt)2]Br (C20H29BrFeNO3P), crystallizes in the triclinic space group P1 with a = 10.926 (3) A?, b = 11.407 (2) A?, c = 10.399 (2) A?, α = 106.53 (1)°, β = 109.40 (2)°, γ = 99.35 (2)°, and Z = 2. Its structure shows the nitrogen atom to be coplanar with its sustituents; the Cp ring lies approximately in the same plane; the N-C2(Cp) bond is short (1.332 (4) A?) and the C2-Fe distance long (2.304 (3) A?).
ALKYLATION OF ORGANOIRON THIOLATE COMPLEXES
Treichel, P. M.,Schmidt, M. S.,Koehler, S. D.
, p. 209 - 216 (2007/10/02)
The iron thiolate complexes Fe(SPh)(CO)(L)(η-C5H5) (L = PMe3, PPh2Me, PPh3, PPh2OMe, PPh(OMe)2, P(OMe)3, P(OPh)3) react with EtBr in CHCl3 (21 deg C) to produce the cationic sulfide complexes, Br.A study of the kinetics of these reactions shows that these reactions are first order in complex and in EtBr; however the rates are largely insensitive to the nature of L in the precursor.After prolonged periods of time, or upon heating, a further reaction ensues in which bromide ion displaces the sulfide ligand to yield FeBr(CO)(L)(η-C5H5).Reactions between Fe(SPh)(CO)2(η-C5H5) and EtBr, and between Fe(SPh)(CO)(PMe3)(η-C5Me5) and EtBr, give FeBr(CO)2(η-C5H5) and FeBr(CO)(PMe3)(η-C5Me5) directly.These reactions presumably also occur via facile ligand loss from the intermediate sulfide complexes.
