There is no Cu(III) btw.
Oh yes, there is. Copper (III) compounds can be made by mixing Na-DCCA or alkaline TCCA with copper (II) sulfate. These compounds have a beautiful purple color, very uncommon for copper.
![](https://www.chemicalforums.com/proxy.php?request=http%3A%2F%2Fwoelen.scheikunde.net%2Fscience%2Fchem%2Fexps%2FTCCA%2FCu-DCCA-1.jpg&hash=b4920618a6a9e49e46341d4f84054c32e305d6cf)
This is possible due to the very strong oxidizing properties of the solution of Na-DCCA (sodium dichloro isocyanuric acid, Na-C3N3O3Cl2). Copper (III) compounds also are said to be achievable by oxidation with concentrated hypochlorites in the cold, but I have not been able to prepare these copper (III) compounds.