[mmx_01]

With all respect - I understand that triplet state of oxygen is the source for alike state in the  unstable peroxide dianion derived from luminol. But on the other hand - doesn't the dianion have all its electrons happily paired - and how then the triplet state occurs - or the dianion is a radical - and why then its radical form is not shown or spelled out explicitly?

[Babcock_Hall]

PMID: 19071703 DOI: 10.1016/j.talanta.2006.12.045

Offhand, I do not know the answer, but the article above is a good review of luminol.  There might be some information in it.