Labilizing the Photoinert: Extraordinarily Facile Photochemical Ligand Ejection in an [Os(N^N)3]2+ Complex

Whilst [Os(N^N)3]2+ complexes are supposed to be photochemically inert to ligand loss, the complex [Os(btz)3]2+ (btz=1,1′‐dibenzyl‐4,4′‐bi‐1,2,3‐triazolyl) undergoes unprecedented photolytic reactivity to liberate free btz (Φ363≈1.2 %). Further, both cis and trans isomers of the photodechelated ligand‐loss solvento intermediate [Os(κ2‐btz)2(κ1‐btz)(NCMe)]2+ are unambiguously observed and characterized by NMR spectroscopy and mass spectrometry. Defying convention: The extraordinary ligand ejection photochemistry of the complex [Os(btz)3]2+ in donor solvents is reported along with observation and characterization of both cis and trans isomers of the ligand‐loss intermediate [Os(κ2‐btz)2(κ1‐btz)(NCMe)]2+ (btz=1,1′‐dibenzyl‐4,4′‐bi‐1,2,3‐triazolyl).