Visible Light Assisted Photocatalytic [3 + 2] Azide−Alkyne “Click” Reaction for the Synthesis of 1,4-Substituted 1,2,3-Triazoles Using a Novel Bimetallic Ru−Mn Complex

<div>A photoactive bimetallic complex comprising a photosensitizer</div><div>ruthenium unit and a catalytic Mn(I) unit connected via a</div><div>bipyrimidine (bpm) bridging ligand is prepared and used for the first</div><div>time for developing a light induced copper catalyzed [3 + 2] azide−</div><div>alkyne “click” (CuAAC) reaction for the formation of 1,2,3-triazoles</div><div>under visible light irradiation. The developed bimetallic complex</div><div>exhibited enhanced activity as both the photosensitizer ruthenium unit</div><div>as well as manganese catalyst unit are attached in a single molecule,</div><div>providing efficient electron transfer for the photochemical reduction of</div><div>Cu(II) to Cu(I) in situ which subsequently was used for the</div><div>cycloaddition of azides with terminal alkynes to give 1,4-disubstituted</div><div>1,2,3-triazoles in the presence of triethylamine as a sacrificial donor.