[opus dei]

Hello world
 Sorry, but I have very little chemistry back ground.
I am trying to figure out exactly what a cognate ligand is in plain English my best guess is that it is a related ligand. I am trying to translate a patent and can not find a good English to Spanish translation of "cognate ligand"

ligandos relacionados = related ligands 
ligandos afinas - sharpened or tuned

I am thinking related legands is the closest I can come

Any Spanish chemists out there that could help

Many thanks Opus