Species Related to Ethenedione

After all these negative findings one might be forgiven being heartened by the synthesis of the oxime of ethenedione, 8, which Maier and coworkers were able to prepare by matrix isolation photolysis at 10Kof9,10, and 11 [35], 

In conventional, wet, chemistry, an oxime is merely a masked ketone, and said ketone can usually be hberated by hydrolysis of the oxime. However, such an approach to ethenedione appears to be quixotic under conventional solution conditions not only would the (probable) ultrashort lifetime of the ketone be an impediment to its spectroscopic observation, but even the generation of this molecule seems unlikely here, because of the sensitivity of the required intermediates along the Itydrolysis pathway, e.g. 0=C=C(OH)NHOH. The synthesis of ethenedione oxime, while clearly interesting, probably ties off the path to the elusive diketone. 

To help put ethenedione in perspective, a quick look is warranted at the state of our knowledge of these related species isomers of ethenedione, the cation and anion of neutral ethenedione, the sulfur analogues OCCS and SCCS, and the imines OCCNH and HNCCNH. 

The cation and anion of neutral ethenedione are well-known. The radical cation, OCCO, was prepared by the reaction of CO with CO, isolated in a neon matrix and studied by ESR supplemented by ab initio calculations [38], and it has also been generated by mass spectrometry [39, 40]. The dication is known too [41, 42]. The radical anion was been reported and subjected to extensive theoretical analysis 

The sulfur analogues OCCS and SCCS are known. Ethenonethione (thioxoethene-dione), OCCS, has been observed by neutrahzation-reionization mass spectroscopy 

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