Formation and Structure of a Cobalt(III) Complex Containing a Nonstabilized Pyridinium Ylide Ligand
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https://figshare.com/articles/dataset/Formation_and_Structure_of_a_Cobalt_III_Complex_Containing_a_Nonstabilized_Pyridinium_Ylide_Ligand/2237170
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资源简介：
The
reaction of [CoIII(4,4′dmsalen)(CH2Cl)(S)], where 4,4′dmsalen = 4,4′-dimethylsalen
and S = solvent, with pyridine led to the formation of [CoIII(4,4′dmsalen)(CH2py)(Cl)], containing a nonstabilized
pyridinium ylide as axial ligand. The complex has been unambiguously
characterized by single-crystal X-ray diffraction analysis. Time-resolved 1H NMR spectra showed that the formation of [CoIII(4,4′dmsalen)(CH2py)(Cl)] occurs in a two-step
process involving a metallacyclized intermediate, cis-β-[CoIII(4,4′dmsalenCH2)(py)(S)]+. A similar experiment carried out in the presence of different
nitrogen bases having higher pKa values
(4-Me-py or 4-t-Bu-py) allowed a better separation
of the two consecutive reactions. The almost complete conversion of
[CoIII(4,4′dmsalen)(CH2Cl)(S)]
in the cyclized intermediate before the formation of the ylide indicates
that the ylide complex forms exclusively through the nucleophilic
attack of the nitrogen base at the −CH2O–
carbon of the cyclized species, whereas a parallel direct conversion
through the displacement of Cl– from the axial CH2Cl group of [CoIII(4,4′dmsalen)(CH2Cl)(S)] may be ruled out.
创建时间：
2016-02-16
