640282-25-3Relevant academic research and scientific papers
Diphenylphosphide-bridged diiron derivatives of [Fe 2(η5-C5H5)2(μ-H) (μ-PPh2)(CO)2]
Alvarez, Celedonio M.,Garcia, M. Esther,Ruiz, Miguel A.,Connelly, Neil G.
, p. 4750 - 4758 (2008/10/09)
The complex trans-[Fe2Cp2(μ-H)(μ-PPh 2)(CO)2] is obtained in 91% yield by refluxing toluene solutions of [Fe2Cp2(CO)4] (Cp = μ5-C5H5) and the secondary phosphine PPh2H. This compound isomerizes upon irradiation with visible - UV light under a CO atmosphere to yield cis-[Fe2Cp2(μ-H) (μ-PPh2)(CO)2]. The above hydride complexes react under photochemical conditions with 1 equiv of secondary phosphines PR2H (R = Et, Ph) to give the corresponding monocarbonyl compounds [Fe 2Cp2(μ-PPh2)(μ-PR2)(μ-CO)] via the hydride intermediates [Fe2Cp2(μ-H)(μ- PPh2)(CO)(PR2H)] (detected and isolated for R = Et). Deprotonation of trans[Fe2Cp2(μ-H)(μ-PPh 2)(CO)2] with LiBu gives the binuclear anion [Fe 2Cp2(μ-PPh2)(CO)2]. This highly nucleophilic carbonylate reacts rapidly with [AuCl(PiPr3)] or MeI to give the corresponding gold diiron cluster [AuFe2Cp 2(μ-PPh2)(CO)2(PiPr3)] or methyl derivative [Fe2Cp2(Me)(μ-PPh 2)(μ-CO)(CO)2], respectively. Both hydrides cis- and trans- [Fe2Cp2(μ-H)(μPPh2)(CO) 2] can be reversibly oxidized at low temperature to the corresponding cation radicals cis- and trans- [Fe2Cp2(μ-H)(H- PPh2)(CO)2]-. At room temperature, however, the trans dicarbonyl cation isomerizes to its cis isomer, which in turn experiences a degradation process involving the reductive elimination of the bridging groups. The structures of the new complexes are analyzed on the basis of the corresponding IR and NMR (1H, 31P and 13C) spectroscopic data. The nature of the new radical cations is analyzed also on the basis of cyclic voltammetry and ESR measurements.
P-C and C-H Bond Cleavages in the Photochemical Reactions of [Fe 2(η5-C5H5)2(CO) 4] with Bis(diphenylphosphino)methane
Alvarez, Celedonio M.,Galan, Belen,Garcia, M. Esther,Riera, Victor,Ruiz, Miguel A.,Vaissermann, Jacqueline
, p. 5504 - 5512 (2008/10/09)
The photochemical reactions of [Fe2Cp2(CO) 4] (Cp = η5-C5H5) and the bidentate ligand Ph2PCH2PPh2 give a complex mixture of products. These include the known complexes [Fe2-Cp 2(μ-CO)2(μ-Ph2PCH2PPh 2)] and cis-[Fe2Cp2(μ-PPh2) 2(CO)2], as well as the new species [Fe 2Cp(μ-η5:κ1-C5H 4CH2PPh2)(μ-CO) 2(CO)],cis-[Fe2Cp2(μ-H)(μ-PPh 2)(CO)2], [Fe2Cp(μ-η 5:κ1-C5H4-CH 2PPh2)(μ-H)(μ-PPh2)(CO)], trans-[Fe 2Cp2(μ-H)(μ-PPh2)(CO)(PMePh 2)], and [Fe2Cp2(μ-PPh2) 2(μ-CO)]. An intermediate species, trans-[Fe2Cp 2(μ-CO)2(CO)(κ1-Ph2PCH 2PPh2)], having an intact diphosphine ligand coordinated through one of the P atoms, can be detected at the early stages of the reaction. Separate experiments indicate that the latter species is the precursor of the unique diphosphine-bridged complex, but of none of the other products. The above results indicate that different P-C (diphosphine) and C-H (cyclopentadienyl) bond cleavage processes are operative under the conditions examined, as well as novel C-C bond formations. The structures of the new complexes are analyzed on the basis of the corresponding IR and NMR ( 1H, 31P, and 13C) data, as well as a single-crystal X-ray study on the (diphenylphosphinomethyl)cyclopentadienyl complex [Fe2Cp(μ-η5:κ1-C 5H5CH2PPh2)-(μ-CO) 2(CO)]. A reassessment of the 31 P chemical shifts for cis- and trans[Fe2Cp2(μ-PPh2)2-(CO) 2 ] is also made.
