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Inicio » Actividades I+D > Publicaciones 2005 > 3-(Triphenylphosphoranylidene)pentane-2,...
artículo con referato
"3-(Triphenylphosphoranylidene)pentane-2,4-dione and diethyl 2-(triphenylphosphoranylidene)malonate"
F. Castañeda, C. Aliaga, C.A. Bunton, M.T. Garland and R. Baggio
Acta Cryst. C 61(8) (2005) o496-o499
The title ylides, 3-(triphenylphosphoranylidene)pentane-2,4-dione, C23H21O2P, (I), and diethyl 2-(triphenylphosphoranylidene)malonate, C25H25O4P, (II), differ in the conformations adopted by their extended ylide moieties. In (I), one carbonyl O atom is syn and the other is anti with respect to the P atom, the ylide group is nearly planar, with a maximum P–C–(C=O) angle of 18.2 (2)°, and the P–C, C–C and C=O bond lengths are consistent with electronic delocalization involving the O atoms. In (II), both carbonyl O atoms are anti and the ester groups are twisted out of the plane of the near trigonal ylide C atom, reducing delocalization, the largest P–C–(C=O) angle being 30.2 (2)°.
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