Amid the art-world big shots at the weekend-long opening festivities for I. M. Pei’s Museum of Islamic Art in Qatar was Robert De Niro, who was seated with the nation’s royal family at the Saturday-night opening ceremony. De Niro and his Tribeca Film Festival co-founders, Jane Rosenthal and Craig Hatkoff, are bringing the festival to the museum next November— an arrangement cooked up by the emir’s daughter, Sheikha Al Mayassa bint Hamad bin Khalifa Al-Thani, 26, after she worked as an intern for the festival in the summer of 2006. (Her initial job was picking up breakfast pastries, she said.) De Niro said he had high hopes for the partnership. New Yorkers’ “stereotypical misconceptions” about Muslims worsened after 9/11, he said, and with the festival, “we have a chance to start altering prejudices.” Perhaps in homage, the local TV station screened GoodFellas, with Arabic subtitles, the evening of the opening.