Coordination Studies of a Triazole‐Substituted 3 <i>H</i> ‐1,2,4‐Diazaphosphole: CC and CN Bond Activation Induced by Cobalt(0) and Nickel(0) Complexes

The reactivity of the recently reported 3 H ‐1,2,4‐diazaphosphole 1 toward electron‐rich Ni and Co complexes is described. Compound 1 reacts with [Ni(cod) 2 ] (cod = 1,5‐cyclooctadiene) to afford complex 2 , which features a 1,2,3‐triazole‐4‐ylidene‐type carbene ligand derived from the cleavage of the CC(Ph) bond in 1 . In contrast, [(IPr)Ni(vtms) 2 ] induces NC( i Pr) bond cleavage of the 1,2,3‐triazole part of 1 (IPr = 1,3‐bis(2,6‐diisopropylphenyl)imidazolin‐2‐ylidene; vtms = H 2 C=CH(SiMe 3 )). The resulting Ni(II) complex 3 additionally features a CH 2 CH 2 SiMe 3 ligand, resulting from a formal H atom transfer to a vtms ligand. Analogous NC( i Pr) bond activations are observed in the reactions of 1 toward [(NHC)Co(vtms) 2 ] (NHC = IPr or IMes; IMes = 1,3‐bis(2,4,6‐trimethylphenyl)imidazolin‐2‐ylidene). However, no H atom transfer is observed in this case, and one vtms ligand is retained in the resulting Co(I) complexes 4 and 5 . The Ni(II) complexes 2 and 3 have square planar molecular structures and are diamagnetic, whereas the Co(I) centers in 4 and 5 exhibit tetrahedral coordination environments, leading to paramagnetic behavior.