This video is the first in a series documenting the preparation of Mo(N[tBu]Ar)3, where Ar = 3,5-C6H3Me2. This is a soluble, three-coordinate molybdenum(III) complex that binds and completely cleaves the dinitrogen molecule. In this episode, the conversion is illustrated of commercially available MoCl5 to MoCl4(OEt2)2 using tin shot as the reducing agent. The preparation is carried out by Dr. John J. Curley in the laboratory of Professor Christopher C. Cummins at the Massachusetts Institute of Technology. For more information visit http://web.mit.edu/ccclab. Less