What is the purple complex that is produced from a slow reaction break down of the cr3- edta complex?

I'm not sure what you are asking for, the structure of the complexed Cr^3+ with EDTA or the one brokendown.

So, here's a site which you might find interesting:

EDTA - MOTM (http://www.chm.bris.ac.uk/motm/edta/edtah.htm#Complexing%20Metals)