Highly unlikely for two reasons :
Elrond, Galadriel and Gandalf were all far too powerful within themselves to fall under Saruman's spells.
Saruman didn't align with Sauron until a long time after The Hobbit's events took place and had no reason to convince them that the Necromancer was not Sauron.
Once he was as great as his fame made him. His knowledge was deep, his thought was subtle, and his hands marvelously skilled; and he had a power over the minds of others. The wise he could persuade, and the smaller folk he could daunt. That power he certainly still keeps. There are not many in Middle-earth that I should say were safe, if they were left alone to talk with him, even now when he has suffered a defeat. Gandalf, Elrond, Galadriel, perhaps, now his wickedness has been laid bare, but very few others.
Aragorn talking to Legolas and Gimli as they enter Orthanc with Gandalf, King Theoden and Eomer to speak with Saruman.
It's highly likely that Saruman was simply skeptical that a Necromancer existed as he believed Sauron had been defeated forever :
Gandalf talks with the White Council (Elrond, Galadriel, and Saruman the White) about his involvement with the Dwarves, explaining the presence Radagast encountered and expresses mild suspicion that this necromancer is the Dark Lord. The others are skeptical, believing Sauron to have been defeated forever, and that this necromancer is not a true threat.