952190-28-2Relevant academic research and scientific papers
Synthesis and reactivity studies of the diphosphine ligand 2-(ferrocenylidene)-4,5-bis(diphenylphosphino)-4-cyclopenten-1,3-dione (fbpcd): Bridge-to-chelate ligand isomerization kinetics in Os3(CO)10(fbpcd) and X-ray diffraction structure of the ortho-metalated cluster HOs3(CO)9[μ-PhP(C6H4)C{do uble bond, long}C...
Watson, William H.,Poola, Bhaskar,Richmond, Michael G.
, p. 3585 - 3594 (2007)
Full title: Synthesis and reactivity studies of the diphosphine ligand 2-(ferrocenylidene)-4,5-bis(diphenylphosphino)-4-cyclopenten-1,3-dione (fbpcd): Bridge-to-chelate ligand isomerization kinetics in Os3(CO)10(fbpcd) and X-ray diffraction structure of the ortho-metalated cluster HOs3(CO)9[μ-PhP(C6H4)C{do uble bond, long}C(PPh2)C(O)C{double bond, long}CH(C5H4FeCp)C(O)] Knoevenagel condensation of ferrocenecarboxaldehyde with 4,5-bis(diphenylphosphino)-4-cyclopenten-1,3-dione (bpcd) yields the new diphosphine ligand 2-(ferrocenylidene)-4,5-bis(diphenylphosphino)-4-cyclopenten-1,3-dione (fbpcd) in near quantitative yield. The reaction of fbpcd with the activated cluster 1,2-Os3(CO)10(MeCN)2 has been examined, with the diphosphine-bridged cluster 1,2-Os3(CO)10(fbpcd) (2b) observed as the major product. Cluster 2b is unstable and transforms into the corresponding chelating isomer 1,1-Os3(CO)10(fbpcd) (2c) on heating. The kinetics associated with the conversion of 2b → 2c have been studied over the temperature range of 313-343 K by 1H NMR and UV-vis spectroscopies. On the basis of the observed activation parameters, a nondissociative isomerization process that involves a transient μ2-bridged phosphine moiety is presented. Near-UV irradiation of cluster 2c leads to CO loss and ortho-metalation of the one of the ancillary phenyl groups to give the hydride cluster HOs3(CO)9[μ-PhP(C6H4)C{do uble bond, long}C(PPh2)C(O)C{double bond, long}CH(C5H4FeCp)C(O)] (3) as a 45:55 mixture of diastereomers. The fbpcd ligand and clusters 2b, 2c, and 3 have been isolated and characterized in solution by IR and NMR (1H and 31P) spectroscopies, and by X-ray diffraction analysis in the case of the hydride-bridged cluster 3.
