I recently was listening to an audio book on the ancient world, and had never really clocked that the Seleucids were named after a bloke called Seleuc, which sounds a lot like Seljuk.
No the similarity is only a coincidence. The Seleukid dynasty was formed in the area roughly encompassing the old Achaemenid empire around the early 300s BC. It was founded by Seleukos Nikator, son of Antiochos.
The Seljuks were a Turkish based power that reigned supreme over the Iranian plateau and Asia minor in the ADs 900s-1200s. I know too little about the Seljuks, so I cannot really help you in that regard.
I hope that answers you question!