Carbene Formation and Transfer at a Dinickel Active Site

The synthesis and reactivity of a dinickel bridging carbene is described. The previously reported [i‑PrNDI]­Ni2(C6H6) complex (NDI = naphthyridine–diimine) reacts with Ph2CN2 to generate a metastable diazoalkane adduct, which eliminates N2 at 60 °C to yield a paramagnetic Ni2(μ-CPh2) complex. The Ni2(μ-CPh2) complex undergoes carbene transfer to t-BuNC via an initial isonitrile adduct, which upon heating releases free t-BuNCCPh2. On the basis of this sequence of stoichiometric reactions, a catalytic carbene transfer reaction is demonstrated.

本工作报道了双核镍桥联卡宾的合成与反应性。此前已报道的[i-PrNDI]Ni₂(C₆H₆)配合物（其中NDI为萘啶二亚胺(naphthyridine–diimine)）与二苯基重氮甲烷(Ph₂CN₂)反应，生成亚稳态重氮烷加合物；该加合物在60 ℃下脱除N₂，得到顺磁性Ni₂(μ-CPh₂)配合物。该Ni₂(μ-CPh₂)配合物可通过初始异腈加合物中间体，与叔丁基异腈(t-BuNC)发生卡宾转移反应；加热该异腈加合物后，可释放出游离的t-BuNCCPh₂。基于上述计量反应序列，本研究实现了催化型卡宾转移反应。