Nitrite impurities in a commercially available palladium catalyst – palladium acetate – can have a serious effect on synthesis, say scientists in the UK and US.
The team found that the impurities affect the synthesis of pure palladium complexes derived from palladium acetate. A previous proposal that the nitrite anion can be formed by oxidation of acetonitrile by metallic palladium and air resulting in cyclo(ortho)palladated complexes containing the nitrite anion, for example Pd(NO2)(C^N)L, can be explained by Pd3(OAc)5NO2 acting as the nitrite source, say the researchers. Finally, photocrystallographic metastable linkage isomerisation and complete conversion to an oxygen-bound nitrito complex Pd(η1-ONO)(C^N)PPh3 has been seen, they add.
Link to journal article
NO2 anion contamination in Pd(OAc)2. On the synthesis of pure Pd(OAc)2L2 and palladacycles containing NO2 anion: the photocrystallographic identification of a metastable Pd(η1-ONO)(C^N)PPh3 complex
S E Bajwa et al, Chem. Sci., 2012, DOI: 10.1039/c2sc01050j
