It is a single-electron process. If you are after a good procedure for 1,4-disubstituted triazole synthesis (click chemistry), you chould visit the existing thread I have linked.
We use Cu(I) supported on macroporous weakly acidic cation exchanger of polyacrylate type, for triazole clic synthesis is very ideal (stable, acts without further ligand, more then 50 times reuseable). Details on request.
Catalyst is available on request at the Tau-Chem Ltd. contact [email protected] .
The thing is patent pending - see link http://worldwide.espacenet.com/publicationDetails/biblio?FT=D&date=20130619&DB=worldwide.espacenet.com&locale=en_EP&CC=CZ&NR=20110799A3&KC=A3&ND=4