Reprinted with permission from ACS ange2019, 131, 5743-5747.  Copyright 2019  American Chemical Society.

LigandBased Control of SingleSite vs. MultiSite Reactivity by a Trichromium Cluster 2Dr. Amymarie K. Bartholomew,  1Dr. Cristin E. Juda Jonathon, 3N. Nessralla, 1Dr. Benjamin Lin, 4Dr. SuYin Grass Wang, 4Dr. Yu‐Sheng Chen, 1Prof. Theodore A. Betley 1.Department of Chemistry and Chemical Biology, Harvard University 12 Oxford St., Cambridge, MA 02138 (USA) 2.Department of Chemistry, Columbia University New York, NY 10027 (USA) 3.Department of Chemistry, University of California, Berkeley Berkeley, CA 94720 (USA) 4.ChemMatCARS Beamline, The University of Chicago, Advanced Photon Source, Argonne, IL 60429 (USA) The trichromium cluster (tbsL)Cr3(thf) ([tbsL]6−=[1,3,5‐C6H9(NC6H4o‐NSitBuMe2)3]6−) exhibits steric‐ and solvation‐controlled reactivity with organic azides to form three distinct products: reaction of (tbsL)Cr3(thf) with benzyl azide forms a symmetrized bridging imido complex (tbsL)Cr3(μ3‐NBn); reaction with mesityl azide in benzene affords a terminally bound imido complex (tbsL)Cr3(μ1‐NMes); whereas the reaction with mesityl azide in THF leads to terminal N‐atom excision from the azide to yield the nitride complex (tbsL)Cr3(μ3‐N). The reactivity of this complex demonstrates the ability of the cluster‐templating ligand to produce a well‐defined polynuclear transition metal cluster that can access distinct single‐site and cooperative reactivity controlled by either substrate steric demands or reaction media. Angew. Chem. 2019, 131, 5743 –5747