Metathesis cleavage of an NN bond in benzo[c]cinnolines and azobenzenes by triply-bonded ditungsten complexes

A metathesis reaction of a WW bond and an NN bond was observed by reacting a W–W triply-bonded W(III)2 complex, (tBuO)3WW(OtBu)3 (1), with benzo[c]cinnoline derivatives to form biphenyl-linked dinuclear (imido)tungsten complexes 2–4. When azobenzene was used as the substrate, a trans to cis isomerization induced by blue-LED light was essential prior to the metathesis cleavage of the NN bond by the WW bond of (Me2N)2(TfO)WW(OTf)(NMe2)2 (6), affording the corresponding imido-bridged dinuclear tungsten complexes 7–9.