Complex sentence: On December 4,2014, Barnes & Noble announced an end to its partnership with Microsoft connected to Nook and that it intended to complete the separation of Nook by the end of the first quarter of 2015.
Split into simpler sentences: On December 4,2014, Barnes & Noble announced an end to its partnership with Microsoft connected to Nook. The company's objective is to take the steps necessary to complete the separation by the end of the first quarter of 2015.