I really dont think neal ever had any real chemistry with anyone. He was almost always an independent contractor out there.
Not that I agree entirely but something to consider is that chemistry aside, playing with good players can obviously boost statistics (especially assists).
My personal opinion as to why Neal was shipped out is because Nieuwendyk didn't think he was a true winning player. I'm sure he'll do fine in Pittsburgh, and may even win a Cup in short order, but I just never got the sense that he has it. That in itself is not a problem but it can be if the player thinks they do.