| Abstrakt: |
Reactions between the 1,3-diphosphete complex [Cp′′′Co(η4-P2C2tBu2)] ( 1) and Ag[Al{OC(CF3)3}4] (Ag[pftb]) were carried out under different conditions. In CH2Cl2, the unprecedented 1,2-diphosphete isomerization product [Ag2{Cp′′′Co(μ,η4:η1:η1-1,2-P2C2tBu2)}2{Cp′′′Co(μ,η4:η1-1,2-P2C2tBu2)}2]⋅2[pftb] ( 2) could be isolated. In diffusion experiments of 1 in n-hexane with Ag[pftb] in CH2Cl2, the triphosphacobaltocenium complex [Cp′′′Co(η5-P3C2tBu2)][pftb] ( 4) and the phosphirenylium complex [Cp′′′Co(η3-PC2tBu2)][pftb] ( 5) were obtained, showing a ring expansion and a ring contraction, respectively, under mild conditions. Moreover, addition of pyridine to the Ag complex 2 led to the new 1,2-diphosphete complex [Cp′′′Co(η4-1,2-P2C2tBu2)] ( 3). Compound 3 is also formed by thermolysis of 1, making it a promising method for this type of isomerization. 1,2-Diphosphete complexes like 3 are thermodynamically more stable but also synthetically more elusive than their 1,3-isomer counterparts. [ABSTRACT FROM AUTHOR] |
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