Iron complex compounds cations, with pyridine

An analogous series of bis(imino)pyridine iron dicarbonyl complexes was also synthesized (Figure 7.7) [38]. Unlike ( PDI)FeN2, ( PDI)Fe(CO)2 exhibits clean and reversible electrochemistry, allowing quantitative measurement of the potentials for one-electron oxidation and reduction. The combined metrical, spectroscopic, and computational data established that the cationic iron dicarbonyl complex [( PDI)Fe(CO)2][BAr 4j is best described as a low-spin iron(I) compound with a neutral bis(imino)pyridine chelate. Both EPR and DFT calculations support a principally iron-based SOMO with significant d 2 character. In the limit where the neutral iron dicarbonyl ( PDI)Fe(CO)2 is viewed in its low-spin Fe(II) canonical form, one-electron oxidation to [( PDI)Fe(CO)2] is pincer-based and results in a net reduction of the metal to Fe(I). 

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